Search This Blog

Wednesday, September 10, 2025

Bantu peoples of South Africa

From Wikipedia, the free encyclopedia
 
Bantu-speaking South Africans/non-Khoisan Black South Africans
Proportion of non-Khoisan Black South Africans in each municipality according to the census
Total population
Increase 50,486,856 (2022 census)
Increase 81.45% of South Africa's population (51.5 Million) 51.5 Million (including those of ancestral descent)
Languages
Religion
Related ethnic groups

Bantu speaking people of South Africa are the majority ethno-linguistic group, native to South Africa. They are descendents of Southern Bantu-speaking peoples who established themselves in the now South Africa, between 350 BCE and 300 CE, during the Bantu expansion (5000 BCE to 500 CE). They are referred to in various census as African, Black or Native South African.

History

The Mapungubwe rhinoceros dated ca. 1250–1290 CE, is part of the Mapungubwe Collection
The Mapungubwe rhinoceros of the Mapungubwe Collection dated c. 1250–1290

Early history

Archaeological evidence suggests that Homo sapiens inhabited the region for over 100,000 years, with agriculture occurring since at least 100 CE. Based on prehistorical archaeological evidence of pastoralism and farming in southern Africa, the findings in sites located in the southernmost region of modern Mozambique, that are dated 354–68 BCE, are some of the oldest and most proximate ancient findings of archaeological evidence related to the South African Bantu-speaking peoples in the south African region. Ancient settlements remains found thus far similarly based on pastoralism and farming within South Africa were dated 249–370 CE.

Around 1220, the Kingdom of Mapungubwe formed in the Shashe-Limpopo Basin, with rainmaking crucial to the development of sacral kingship. Venda tradition holds the two kings were called Shiriyadenga and Tshidziwelele. Mapungubwe collapsed around 1300 for unknown reasons, although shifting trade routes north to Great Zimbabwe likely contributed to its demise. The population dispersed, and didn’t regroup.

Interactions with Europeans

When the early Portuguese sailors Vasco Da Gama and Bartholomew Dias reached the Cape of Good Hope in the late 15th century CE, a number of Khoe language speakers were found living there and the indigenous population around the Cape primarily consisted of Khoisan groups. Following the establishment of the Dutch Cape Colony, European settlers began arriving in Southern Africa in substantial numbers. Around the 1770s, Trekboers from the Cape encountered more Bantu language speakers towards the Great Fish River and frictions eventually arose between the two groups. In the late 18th and early 19th centuries, there were two major areas of frictional contact between the white colonialists and the Bantu language speakers in Southern Africa. Firstly, as the Boers moved north inland from the Cape they encountered Xhosa, Basotho, and Tswana peoples. Secondly attempts at coastal settlement was made by the British in two regions now known as the Eastern Cape and KwaZulu-Natal.

"Empty Land" myth

The history of the Bantu-speaking peoples from South Africa has in the past been misunderstood due to the deliberate spreading of false narratives such as The Empty Land Myth. First published by W.A. Holden in the 1860s, this doctrine claims that South Africa had mostly been an unsettled region and that Bantu-speaking peoples had begun to migrate southwards from present day Zimbabwe at the same time as the Europeans had begun to move northwards from the Cape settlement, despite there being no historical or archaeological evidence to support this theory.

This theory originated in Southern Africa during the period of Colonisation of Africa, historians have noted that this theory had already gained currency among Europeans by the mid-1840s. Its later alternative form of note were conformed around the "1830s concept of Mfecane", trying to hide and ignore the intrusion of Europeans on Bantu lands, by implying that the territory they colonized was devoid of human habitation (as a result of the Mfecane). Modern research has disputed this historiographical narrative. By the 1860s, when Holden was propagating his theory, this turbulent period had resulted in large swathes of South African land falling under the control of either the Boer Republics or British colonials, there was denaturalisation accompanied with forced displacement and population transfer of these indigenous peoples from their land, the myth being used as the justification for the capture and settlement of Bantu-speaking peoples's land. The Union of South Africa established rural reserves in 1913 and 1936, by legislating the reduction and voiding of South African Bantu-speaking peoples's land heritage holistically, thereby land relating to Bantu-speaking peoples of South Africa legislatively became reduced into being those reserves. In this context, the Natives Land Act, 1913, limited Black South Africans to 7% of the land in the country. In 1936, through the Native Trust and Land Act, 1936, Union of South Africa's government planned to raise this to 13.6% but subsequently would not.

The National Party (South Africa) government, the Apartheid government became the profundity action from the pre-1948 Union of South Africa's government rule, it introduced a series of measures that reshaped the South African society such that Europeans would take themselves as the demographic majority while being a minority group. The creation of false homelands or Bantustans (based on dividing South African Bantu language speaking peoples by ethnicity) was a central element of this strategy, the Bantustans were eventually made nominally independent, in order to limit South African Bantu language speaking peoples citizenship to those Bantustans. The Bantustans were meant to reflect an analogy of the various ethnic "-stans" of Western and Central Asia such as the Kafiristan, Pakistan, etc. But in South Africa, the association with Apartheid discredited the term, and the Apartheid government shifted to the politically appealing but historically deceptive term "ethnic homelands". Meanwhile, the Anti-Apartheid Movement persisted in calling the areas Bantustans, to actively protest the Apartheid governments' political illegitimacy. The fallacy of The Empty Land Myth also completely omits the existence of the Saan (hunter-gatherers) and the Khoikhoi (pastoralists) in southern Africans, who roamed much of the southwestern region of Africa for millenniums before the invasions, colonialism of Europeans.

The Mfecane and colonisation

Xhosa Wars

The longest running military action from the period of colonialism in Africa, which saw a series of nine wars during 1779 till 1879. Involving the Xhosa Kingdom and the British Empire, mainly in the present day South African region of Eastern Cape.

(1779–1803): After European invasion of the present day Western Cape, South Africa region, colonialist's frontiersmen in the 18th century started encroaching the land farther inland present-day South African region, encountering more of the indigenous population, conflict of land and cattle grew sparking the first war that set to drive Xhosa people out of Zuurveld by 1781. The second war involved a larger Xhosa territory between the Great Fish River and the Sundays River, the Gqunukhwebe clans of the Xhosa started to penetrate back into the Zuurveld and colonists under Barend Lindeque, allied themselves with Ndlambe, a regent of the Western Xhosas, to repel the Gqunukhwebe. The second war concluded when farms were abandoned due to panic in 1793. In 1799 the third war began with the Xhosa rebellion – discontented Khoekhoe revolted and joined with the Xhosa in the Zuurveld, and started retaking land through farms occupied by colonialist, reaching Oudtshoorn by July 1799. The colonial officials made peace with the Xhosa and Khoe in Zuurveld. In 1801, Graaff-Reinet rebellion started forcing more Khoekhoe desertions and farm abandonment. The commandos could not achieve any result, so in February 1803 a peace was arranged with the Xhosas and Khoekhoes.

(1811–1819): Zuurveld became a buffer zone between the Cape Colony and Xhosa territory, empty of the Boers, the British to the west and the Xhosa to the east. In 1811 the fourth war began when the Xhosa took back the rest of their territory of Zuurveld, conflicts with the settlers followed. Forces under Colonel John Graham drove the Xhosa back beyond the Fish River. The fifth war, the war of Nxele, started after the Battle of Amalinde. This happened after a civil war broke out within the Xhosa Nation when the British-allied chief Ngqika of the Right Hand House allegedly tried to overthrow the Government and become the king of the Xhosas but was defeated. Then Ngqika appealed to the British who seized 23,000 head of cattle from a Xhosa chief. The Xhosa prophet, Nxele (Makhanda) emerged, under the command of Mdushane, Ndlambe's son, led 6,000 Xhosa force attack on 22 April 1819 to Grahamstown, which was held by 350 troops repulsed Nxele. Nxele was captured and imprisoned on Robben Island. The British pushed the Xhosa further east beyond the Fish River to the Keiskamma River. The resulting empty territory was designated as a buffer zone for loyal Africans' settlements. It came to be known as the "Ceded Territories".

(1834–1879): The Xhosa remained expelled from their territory dubbed "Ceded Territories", that was then settled by Europeans and other African peoples. They were also subjected to territorial expansions from other Africans that were themselves under pressure from the expanding Zulu Kingdom. Nevertheless, the frontier region was seeing increasing amounts of multi-racial issues because Africans and Europeans living and trading throughout the frontier region. The indecision by the Cape Government's policy towards the return of the Xhosa territories did not dissipate Xhosa frustration toward the inability to provide for themselves, hence the Xhosa resorted to frontier cattle-raiding. In response on 11 December 1834, a Cape government commando party killed a chief of high rank, incensing the Xhosa army of 10,000 led by Maqoma, that swept across the frontier into the Cape Colony. A string of defeats by Sir Benjamin d'Urban combining forces under Colonel Sir Harry Smith stopped the Xhosa, most Xhosa chiefs surrendered but the primary leadership Maqoma and Tyali retreated, a treaty was imposed and hostilities finally died down on 17 September 1836. Aftermath the sixth war, a chief believed to be actually the paramount chief or the King of the Gcaleka Xhosa by the Cape Colony, Chief Hintsa ka Khawuta, was shot and killed by George Southey, brother of Richard Southey. The era also saw the rise and fall of Stockenström's treaty system.

The seventh war became a war between the imperial British troops collaborating with the mixed-race "Burgher forces", which were mainly Khoi, Fengu, British settlers and Boer commandos, against the Ngcika assisted by the Ndlambe and Thembu. Tension had been simmering between colonialist farmers and Xhosa raiders, on both sides of the frontier since the dismantlement of Stockenstrom's treaty system. This began when Governor Maitland imposed a new system of treaties on the chiefs without consulting them, while a severe drought forced desperate Xhosa to engage in cattle raids across the frontier to survive. In addition, politician Robert Godlonton continued to use his newspaper the Graham's Town Journal to agitate for 1820 Settlers to annex and settle the land that had been returned to the Xhosa after the previous war. The war concluded after the announcement of the annexation of the country between the Keiskamma and the Kei rivers to the British crown by order of Lord Glenelg. It was not, however, incorporated with the Cape Colony, but made a crown dependency under the name of British Kaffraria Colony with King William's Town as its capital.

Large numbers of Xhosa were displaced across the Keiskamma by Governor Harry Smith, and these refugees supplemented the original inhabitants there, causing overpopulation and hardship. Those Xhosa who remained in the colony were moved to towns and encouraged to adopt European lifestyles. In June 1850 there followed an unusually cold winter, together with an extreme drought. It was at this time that Smith ordered the displacement of large numbers of Xhosa squatters from the Kat River region. The war became known as "Mlanjeni's War", the eighth war, after the prophet Mlanjeni who arose among the homeless Xhosa and preached mobilization, large numbers of Xhosa began leaving the colony's towns and mobilizing in the tribal areas. In February 1852, the British Government decided that Sir Harry Smith's inept rule had been responsible for much of the violence, and ordered him replaced by George Cathcart, who took charge in March. In February 1853 Xhosa chiefs surrendered, the 8th frontier war was the most bitter and brutal in the series of Xhosa wars. It lasted over two years and ended in subjugation of the Ciskei Xhosa.

The cattle-killing movement that began in 1856 to 1858, led Xhosa people to destroy their own means of subsistence in the belief that it would bring about salvation from colonialism through supernatural spirits. First declared by a prophetess Nongqawuse no one believed in the prophecy and it was considered absurdity, but more and more people started believing Nongqawuse. The cult grew and built up momentum, sweeping across the eastern Cape. The return of the ancestors was predicted to occur on 18 February 1857, when the day came, the Xhosa nation waited en masse for the momentous events to occur, only to be bitterly disappointed. Famine set in and disease was also spread from the cattle killings, this forced the remainder of the Xhosa nation to seek relief from colonialists.

In 1877 the ninth of the Cape frontier war happened, known as the "Fengu-Gcaleka War", and also the "Ngcayechibi's War" — the name stemming from a headman whose feast was where the initial fight occurred that traces from the conflicts of this war.

Creation of the Zulu Kingdom

Before the early 19th century the indigenous population composition in KwaZulu-Natal region was primarily by many different, largely Nguni-speaking clans and influenced by the two powers of the Mthethwa and the Ndwandwe. In 1816, Shaka acceded to the Zulu throne (at that stage the Zulu was merely one of the many clans). Within a relatively short period of time he had conquered his neighbouring clans and had forged the Zulu into the most important ally of the large Mthethwa clan, which was in competition with the Ndwandwe clan for domination of the northern part of modern-day KwaZulu-Natal.

Depicted muster and dance performance of Zulu regiments, c. 1827

After the death of the Mthethwa king Dingiswayo around 1818, at the hands of Zwide, the king of the Ndwandwe, Shaka assumed leadership of the entire Mthethwa alliance. The alliance under his leadership survived Zwide's first assault at the Battle of Gqokli Hill. Within two years he had defeated Zwide at the Battle of Mhlatuze River and broken up the Ndwandwe alliance, some of whom in turn began a murderous campaign against other Nguni communities, resulting in a mass migration of communities fleeing those who are regarded now as Zulu people too. Historians have postulated this as the cause of the Mfecane, a period of mass migration and war in the Southern African interior in the 19th, however this hypothesis is no longer accepted by most historians, and the idea itself of Mfecane/Difaqane has been thoroughly disputed by many scholars, notably by Julian Cobbing.

Pedi Kingdom

The Pedi polity under King Thulare (c. 1780–1820) was made up of land that stretched from present-day Rustenburg to the lowveld in the west and as far south as the Vaal River. Pedi power was undermined during the Mfecane, by the Ndwandwe. A period of dislocation followed, after which the polity was re-stabilised under Thulare's son Sekwati.

Sekwati succeeded King Thulare as paramount chief of the Bapedi in the northern Transvaal (Limpopo). He engaged in maintaining his domain from other indigenous polities, mostly in frequent conflict with Mzilikazi's army who then had established and residing in Mhlahlandlela (present day Centurion, Gauteng) after retreating King Sigidi kaSenzagakhona's forces, before they moved on to found the Kingdom of Mthwakazi, the Northern Ndebele Kingdom.

Sekwati was also engaged in struggles over land and labour with the invading colonialists. These disputes over land started in 1845 after the arrival of Boers and their declaring of Ohrigstad in King Sekwati's domain, in 1857 the town was incorporated into the Transvaal Republic and the Republic of Lydenburg was formed, an agreement was reached that the Steelpoort River was the border between the Pedi and the Republic. The Pedi were well equipped for waging war though, as Sekwati and his heir, Sekhukhune I were able to procure firearms, mostly through migrant labour from the Kimberley diamond fields and as far as Port Elizabeth. On 16 May 1876, Thomas François Burgers, president of the South African Republic (ZAR), not to be confused with the modern-day Republic of South Africa, caused the First of the Sekhukhune Wars when he declared war against the Bapedi Kingdom, the Burgers' army was defeated on 1 August 1876. The Burgers' government later hired the Lydenburg Volunteer Corps commanded by a German mercenary Conrad von Schlickmann, they were repelled and Conrad was killed in later battles.

On 16 February 1877, the two parties, mediated by Alexander Merensky, signed a peace treaty at Botshabelo. This led to the British annexation of the South African Republic (ZAR) on 12 April 1877 by Sir Theophilus Shepstone, a secretary for native affairs of Natal at that time. The Second of Sekhukhune Wars commenced in 1878 and 1879 with three British attacks that were successfully repelled but Sekhukhune was defeated in November 1879 by Sir Garnet Wolseley's army of twelve thousand, made up of the 2,000 British, Boers and 10,000 Swazis, Swazis joined the war in support of Mampuru II's claim to the Bopedi (Pedi Kingdom) throne. This brought about the Pretoria Convention of 3 August 1881, which stipulated Sekhukhune's release on reasons that his capital was already burned to the ground. Sekhukhune I was murdered by assassination on alleged orders from his half brother Mampuru II due to the existing dispute to the throne, as Mampuru II had been ousted by Sekhukhune before being reinstalled as King of Bopedi by the British after the British invasion of Bopedi. King Mampuru II was then arrested and executed by the treaty restored Boer South African Republic (ZAR) on charges of public violence, revolt and the murder of his half brother. The arrest was also well claimed by others to be because of Mampuru's opposition to the hut tax imposed on black people by the South African Republic (ZAR) in the area.

Mampuru II has been described as one of South Africa's first liberation icons. Potgieter Street in Pretoria and the prison where he was killed was renamed in his honour, in February 2018 a statue of Mampuru was proposed to be erected in Church Square, Pretoria where it will stand opposite one of Paul Kruger who was President of the British's South African Republic (ZAR) at the time of Mampuru's execution. The Pedi paramountcy's power was also cemented by the fact that chiefs of subordinate villages, or kgoro, take their principal wives from the ruling house. This system of cousin marriage resulted in the perpetuation of marriage links between the ruling house and the subordinate groups, and involved the payment of inflated bohadi or bride wealth, mostly in the form of cattle, to the Maroteng house.

Inception of apartheid

Bantu publication by the apartheid government, February 1959

The Apartheid government retained and continued on from 1948 with even more officiation and policing on racial oppression of Bantu-speaking peoples of South Africa for 48 years. Decades before the inception of Apartheid there was a Rand Rebellion uprising in 1922 which eventually became an open rebellion against the state, it was against mining companies whose efforts at the time, due to economic situations, were nullifying irrational oppression of natives in the work place. The pogroms and slogans used in the uprising against blacks by whites articulated that irrationally oppressing Bantu-speaking peoples of South Africa was much more a social movement in European communities in the 20th century South Africa, before ever becoming government in 1948 which happened through a discriminatory vote by only white, minority people in South Africa, that formed a racist, well resourced and a police state of an illegitimate government for nearly 50 years. In the 1930s, this irrational oppression/discrimination was already well supported by propaganda, e.g. the Carnegie Commission of Investigation on the Poor White Question in South Africa, it served as the blueprint of Apartheid.

Democratic dispensation

A non-racial system franchise known as Cape Qualified Franchise was adhered to from year 1853 in the Cape Colony and the early years of the Cape Province which was later gradually restricted, and eventually abolished, under various National Party and United Party governments. It qualified practice of a local system of multi-racial suffrage. The early Cape constitution which later became known as the Cape Liberal tradition.

When the Cape's political system was severely weakened, the movement survived as an increasingly liberal, local opposition against the Apartheid government of the National Party. In the fight against Apartheid, African majority took the lead in the struggle, as effective allies the remaining Cape liberals against the growing National Party, engaged to a degree in collaboration and exchange of ideas with the growing African liberation movements, especially in the early years of the struggle. This is seen through the non-racial values that were successfully propagated by the political ancestors of the African National Congress, and that came to reside at the centre of South Africa's post-Apartheid Constitution.

Nelson Mandela
Nelson Mandela (1918–2013), the first democratically elected president of South Africa, a Thembu (Xhosa ethnicity), one of the Bantu-speaking peoples of South Africa

The year 1994 saw the first democratic election in South Africa, the majority of the population, Black South Africans, participating in political national elections for the first time in what ceremonially ended the Apartheid era and also being the first time a political party in South Africa getting legitimately elected as government. The day was ideally hailed as Freedom day and the beginning of progress to the conclusion of Black South Africans existential struggle that began with European colonisation in the South African region.

As a consequence of Apartheid policies, black Africans are regarded as a race group in South Africa. These groups (blacks, whites, Coloureds and Indians) still tend to have a strong racial identities, and to classify themselves, and others, as members of these race groups and the classification continues to persist in government policy, to an extent, as a result of attempts at redress such as Black Economic Empowerment and Employment Equity.

Ethnic groups

African – ethnic or racial reference in South Africa is a synonym to Black South Africans. It is also used to refer to expatriate Black people from other African countries who are in South Africa.

South Africa's Bantu language speaking communities are roughly classified into four main groups: Nguni, Sotho–Tswana, Vhavenda and Shangana–Tsonga, with the Nguni and Basotho-Tswana being the largest groups, as follows:

Culture

Black people in South Africa were group-related and their conception of borders based on sufficient land and natural features such as rivers or mountains, which were not by any means fixed.

Common among the two powerful divisions, the Nguni and the Sotho–Tswana, are patrilineal societies, in which the leaders formed the socio-political units. Similarly, food acquisition was by pastoralism, agriculture, and hunting. The most important differences are the strongly deviating languages, although both are Southern Bantu languages, and the different settlement types and relationships. In the Nguni settlements villages were usually widely scattered, whereas the Sotho–Tswana often settled in towns.

Language and communication

The majority of Bantu languages spoken in South Africa are classified as belonging to one of two groups. The Nguni languages (such as Xhosa, Zulu, Ndebele, and Swazi), whose speakers historically occupied mainly the eastern coastal plains, and the Sotho–Tswana languages (such as the Southern Sotho, Tswana, Northern Sotho) and whose speakers historically lived on the interior plateau. The two language groups differ in certain key aspects (especially in the sound systems), with the rest of South African Bantu languages (Venda and Tsonga) showing even more unique aspects. Significant number of Black South Africans are native multilingual, speaking two or more languages as their first language, mainly from languages of South Africa.

Ditema syllabary

The composition of the syllables of the words "Xilo" [ʃiːlɔ] "thing" in Xitsonga, "Vhathu" [βaːtʰu] "people" in Tshivenḓa and "Ho tlêtse" [hʊt͜ɬ’ɛːt͜s’ɪ] "It is full" in Sesotho, using Ditema syllabary

A constructed script of featural writing system and syllabary, whose developments in 2010 was inspired by ancient ideographic traditions of the Southern African region, and its parent systems being Amabheqe ideographs and Litema. It was developed for siNtu. The origins of Litema ornamental and mural art of Southern Africa stretches centuries back in time, while excavations at Sotho-Tswana archaeological sites have revealed hut floors that have survived the elements for 1500 years, the earliest intact evidence of this art stretches back from the c. 1400s.

Southern Ndebele paintings

A Southern Ndebele artist signs her work on a finished wall.

Southern Ndebele prior and during the 18th century primarily used their expressive symbols for communication, it is believed that these paintings are a synthesis of historical Nguni design traditions and Northern Sotho ditema or litema tradition(s). They also began to stand for their continuity and cultural resistance to their circumstances during the colonisation in the 19th century. These wall paintings done by the women was their secret code to their people, disguised to anyone but the Southern Ndebele. The vibrant symbols and expressions portray communications of personal prayers, self-identification, values, emotions, and marriage, sometimes the male initiation but the ritual was not expressed. Religions have never been a part of the Southern Ndebele's house paintings. The women of the Southern Ndebele are often the tradition carriers and the main developer of the wall art of their home. The tradition and style of house painting is passed down in the families from generation to generation by the mothers. A well-painted home shows the female of the household is a good wife and mother. She is responsible for the painting of the outside gates, front walls, side walls, and usually the interior of her home. One thing that has changed since the beginning of the paintings and the present-day wall art is their styles. In the late 1960s, the new style was evident, what was once a finger-painted creation was now created using bundled twigs with feathers as brushes. The walls are still originally whitewashed, but the outlines and colours have significantly changed.

The patterns and symbols can be seen today with a rich black outline and a vivid colour inside. There are five main colours represented: red and dark red, yellow to gold, a sky blue, green, and sometimes pink, white is always used as the background because it makes the bright patterns stand out more. The geometric patterns and shape are first drawn with the black outline and later filled in with colour. The patterns are grouped together throughout the walls in terms of their basic design structure. Creating the right tools to allow accuracy and freedom becomes a difficult task. The tools can't restrict the painter from creating her art. They have to have tools for the large geometric shapes of flat colour and small brushes for the very small areas, outlines, and sacks. The advancement of tools has allowed faster and more complex designs throughout the Southern Ndebele's homes. Every generation passes it down and little changes become apparent.

Traditional sports and martial arts

A Bafana Bafana fan with the famous South African Association football supporter's accessories, the Makarapa and the Vuvuzela

The most popular sporting code in South Africa and among Black South Africans is Association football with the most notable event having been hosted being the 2010 FIFA World Cup, but before such advent there are historical sports that were popular to the indigenous.

Nguni stick-fighting

It is a martial art historically practiced by teenage Nguni herdboys in South Africa. Each combatant is armed with two long, hard sticks, one of which is used for defense and the other for offense with little or no armor used. Although Xhosa styles of fighting may use only two sticks, variations of Nguni stick-fighting throughout Southern Africa incorporate shields as part of the stick-fighting weaponry. Zulu stick-fighting uses an isikhwili, an attacking stick, and ubhoko, a defending stick or an ihawu, a defending shield. The objective is for two opposing warriors to fight each other to establish which of them is the strongest or the "Bull" (Inkunzi). An "induna" or War Captain becomes a referee for each group of warriors, keeps his crew in check and keeps order between fighters. Warriors of similar affiliation did this when engaging in combat with one another. In modern times this usually occurs as a friendly symbolic practice part of the wedding ceremony, where warriors (participants) from the bridegroom's household welcome warriors from the bride's household. Other groups of participants may also be welcomed to join in.

Musangwe

A traditional, bare-knuckle, combat sport of Venda people. It resembles bare-knuckle boxing.

Sociopolitical organisation

It is well documented in the Apartheid legislation, that the white minority, government regime – recreated and used the "traditional" Chiefdom-ships system to be the National Party's power reach, and even increased the Chiefdom-ships' powers over the Bantu-speaking peoples of South Africa for the Apartheid government's interests. This was after colonial regimes and subsequent South African governments before formal Apartheid, had initiated the taking of most of South African land from the indigenous peoples. Most of South African land began being made an exclusive possession of only white minority Europeans in South Africa legislatively by 1913.

Until very recently, South African Bantu-speaking communities were often divided into different clans, not around national federations, but independent groups from some hundreds to thousands of individuals. The smallest unit of the political organisational structure was the household, or kraal, consisting of a man, woman or women, and their children, as well as other relatives living in the same household. The man was the head of the household and often had many wives, and was the family's primary representative. The household and close relations generally played an important role. Households which lived in the same valley or on the same hill in a village were also an organisational unit, managed by a sub-chief.

Chiefdom-ship was largely hereditary, although chiefs were often replaced when not effective. In most clans the eldest son inherited the office of his father. In some clans the office was left to the oldest brother of the deceased chief, and after his death again the next oldest brother. This repeated until the last brother died. Next was the eldest son of the original chieftain; then the oldest one of the brothers as the leader.

The chief was surrounded with a number of trusted friends or advisors, usually relatives like uncles and brothers, rather than influential headmen or personal friends. The degree of the democracy depended on the strength of the chieftain. The more powerful and more influential a chieftain was, the less the influence of his people. Although the leader had much power, he was not above the law. He could be criticised both by advisors as well as by his people, and compensation could be demanded. The people were divided into different clans or tribes which had their own functions, laws, and language.

Time-reliant traditions

Traditionally Pleiades star cluster, in the Xhosa calendar symbolizes the beginning of the year called in Xhosa.

Xhosa calendar

Xhosa people historically and traditionally based their agricultural time on reliable star systems. When these traditions are aligned with the Gregorian calendar system the Xhosa year begins in June and ends in May when the Canopus star (in Xhosa: UCanzibe) becomes visible in the Southern hemisphere, this signaled their time for harvesting.

Sotho calendar

Sesotho months (in Sotho: Likhoeli) indicate special natural and agricultural events of Southern Africa. Traditionally and historically, being cattle breeders who lived in the semi-arid regions of Southern Africa, a deep understanding of agriculture and the natural world was essential for their survival. Sesotho speaking people generally recognise only two seasons called Dihla. However, names do exist aligned to all four of the traditional Western seasons. The Sotho year begins approximately in August or September, a time when their crops were planted.

Traditional holidays

First Fruits

A ceremony of giving the first fruits in a harvest to God, or the gods who are believed to be responsible for the abundance of food in Southern Africa. Traditionally it marked a time of prosperity, in the good harvests experienced after the seasonal agricultural period. It also brought people together, unifying them at a time of merry making and quashing fears of famine. In South Africa the tradition is practiced by Zulu people of KwaZulu-Natal as Umkhosi Wokweshwama.

Umkhosi womHlanga

Umhlanga is an annual event that originates from Eswatini in the 1940s from the rule of King Sobhuza II, it is an adaptation of a much older ceremony of Umchwasho. In South Africa it was introduced by the Zulu King Goodwill Zwelithini kaBhekuzulu in 1991 to be later known as Umkhosi womHlanga, as a means to encourage young Zulu girls to delay sexual activity until marriage. All girls are required to undergo a virginity test before they are allowed to participate in a royal dance, they wear a traditional attire, including beadwork, and izigege, izinculuba and imintsha, with anklets, bracelets, necklaces, and colourful sashes. Each sash has appendages of a different colour, which denote whether or not the girl is betrothed. These young women then participate in a traditional dance bare-breasted, while each maiden carries a long reed – the girls take care to choose only the longest and strongest reeds – and then carry them towering above their heads in a slow procession up the hill to the royal Enyokeni Palace. The procession is led by the chief Zulu princess.

Historical food acquisition

Food acquisition was primarily limited to types of agriculture (slash and burn and Intensive subsistence farming), pastoral farming and engaging in hunting. Generally women were responsible for Crop agriculture and men went to herd and hunt except for the Tsonga (and partially the Mpondo). Fishing was relatively of little importance. All Bantu-speaking communities commonly had clear separation between women's and men's tasks.

Nguni cattle roaming and resting on a beach, South Africa.

Essentially they consumed meat (primarily from Nguni cattle, Nguni sheep (Zulu sheep, Pedi sheep, Swazi sheep), pigs/boars and wild game hunts), vegetables, fruits, cattle and sheep milk, water, and grain beer on occasion. They began to eat the staple product of maize mid-18th century (introduced from the Americas by Portuguese in the late 17th century via the East African coast), it became favoured for its productiveness which was more than the grains of South African native grasses. There were a number of taboos regarding the consumption of meat. The well known, no meat of dogs, apes, crocodiles or snakes could be eaten. Likewise taboo was the meat of some birds, like owls, crows and vultures, as well as the flesh of certain totem animals. The mopane worms are traditionally popular amongst the Tswana, Venda, Southern Ndebele, Northern Sotho and Tsonga people, though they have been successfully commercialised.

South African Bantu language speaking peoples' modern diet is largely still similar to that of their ancestors, but significant difference being in the systems of production and consumption of their food. They do take interest to innovations in foods that come their way while still practicing their very own unique food cuisine popular amongst themselves and those curious alike.

Pre-colonial and traditional house types

Historically, communities lived in two different types of houses before this tradition was dominated by one, the Rondavel. The Nguni people usually used the beehive house, a circular structure made of long poles covered with grass. The huts of the Sotho–Tswana people, Venda people and Shangana–Tsonga people, used the cone and cylinder house type. A cylindrical wall is formed out of vertical posts, which is sealed with mud and cow dung. The roof built from poles tied-together, covered with grass. The floor of both types is compressed earth.

The Rondavel itself developed from the general, grass domed African-style hut nearly 3 000 years ago, its first variety, the veranda Rondavel, emerged about 1 000 years ago in southern Africa. Colonial housing styles inspired the rectangular shaping of the Rondavel from the 1870s, this is regarded as the beginning of the Rondavel's westernisation that sees this African indigenous invention even today being popularly known as the Rondavel, (a derivative of Afrikaans: Rondawel), instead of its indigenous name(s). Constraints caused by urbanisation produced a highveld type of style housing, shack-like, structures coalesced with corrugated metal sheeting (introduced during the British colonisation), this marked a significant visible change in the southern African region, it attested to the contemporary pressures of South African Bantu-speaking peoples's realities, especially that of resources.

Ideologies

Umvelinqangi

Umvelinqangi according to mainly Xhosa and Zulu people's culture is the Most High or Divine Consciousness, is the source of all that has been, that is and all that ever will be. It's the inner light of creation. Ukukhothama (similar to meditation) prior to Colonization/Westernization was a widespread practice in South Africa noticeably by those considered Zulu people now, it was seen as a way of attaining oneness (in Zulu: Ubunye), with the divine conscious.

King Shaka's philosophy

Statue portraying King Shaka kaSenzangakhona, London, UK.

King Shaka is well known for the many military, social, cultural and political reforms he used to create his highly organised and centralised Zulu state. The most important of these were the transformation of the army, thanks to innovative tactics and weapons he conceived, and a showdown with the spiritual leadership, limiting the power of traditional healers, and effectively ensuring the subservience of the Zulu church to the state. King Shaka integrated defeated Zulu-speaking tribes into the newly formed Zulu ethnic group, on a basis of full equality, with promotions in the army and civil service being a matter of merit rather than circumstance of birth.

Black Consciousness Movement

An anti-Apartheid movement that emerged in South Africa in the mid-1960s. BCM attacked what they saw as traditional white values, especially the "condescending" values of white people of liberal opinion and emphasised the rejection of white monopoly on truth as a central tenet of their movement. The BCM's policy of perpetually challenging the dialectic of Apartheid South Africa as a means of transforming Black thought into rejecting prevailing opinion or mythology to attain a larger comprehension brought it into direct conflict with the full force of the security apparatus of the Apartheid regime.

Ubuntu philosophy

A concept that began to be popularised in the 1950s and became propagated by political thinkers specifically in Southern Africa during the 1960s. Ubuntu asserts that society, not a transcendent being, gives human beings their humanity. An "extroverted communities" aspect is the most visible part of this ideology. There is sincere warmth with which people treat both strangers and members of the community. This overt display of warmth is not merely aesthetic but enables formation of spontaneous communities. The resultant collaborative work within these spontaneous communities transcends the aesthetic and gives functional significance to the value of warmth. It is also implied that Ubuntu is in the ideal of that everyone has different skills and strengths; people are not isolated, and through mutual support they can help each other to complete themselves.

Notable people

Notable Black people of South Africa include contributors, scholars and professionals from a range of diverse and broad fields, also those who are laureates of national and international recognition and certain individuals from South African monarchs.

The list of notable Black South Africans includes a diverse range of individuals who have made significant contributions in various fields, including academia, politics, sports, and the arts. Here are some examples of notable Black South Africans who have achieved recognition nationally and internationally:

Academics and Scholars: Mojuta Steven Mothlamme: A prominent scholar who has made significant contributions to the field of epistemology and the study of black academics under apartheid.William Anderson Soga Z. K. Matthews: A renowned academic and anti-apartheid activist who was the first black vice-chancellor of the University of Fort Hare. Nomalanga Mkhize: A prominent academic and humanitarian who has made significant contributions to the field of African studies and humanitarianism. Njabulo Ndebele: The Principal of the University of Cape Town and a prominent figure in South African academia.

Politicians and Activists: Nelson Mandela: The first democratically elected president of South Africa and a Nobel Peace Prize laureate for his role in the fight against apartheid. F.W. de Klerk: The last State President of South Africa under apartheid and a Nobel Peace Prize laureate for his role in the country's transition to democracy. Anwar Sadat: The President of Egypt who was awarded the Nobel Peace Prize in 1978 for his efforts to reach a peace agreement between Egypt and Israel.

Sports: Black and mixed race people who have black south African dna who have made significant contributions to sports in South Africa, particularly during the apartheid era, despite facing numerous challenges and obstacles.

Arts and Culture: Benedict Wallet Vilakazi: A prominent author, educator, and the first black South African to receive a PhD.

Monarchs: The list of notable Black South Africans includes individuals from various monarchies, such as the Zulu Kingdom, the Xhosa Kingdom, and the Sotho Kingdom, who have played significant roles in shaping the country's history and culture.

These individuals, among many others, have made significant contributions to various fields, breaking barriers and paving the way for future generations.

Horizontal gene transfer

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Horizontal_gene_transfer
Tree of life showing vertical and horizontal gene transfers

Horizontal gene transfer (HGT) or lateral gene transfer (LGT) is the movement of genetic material between organisms other than by the ("vertical") transmission of DNA from parent to offspring (reproduction). HGT is an important factor in the evolution of many organisms. HGT is influencing scientific understanding of higher-order evolution while more significantly shifting perspectives on bacterial evolution.

Horizontal gene transfer is the primary mechanism for the spread of antibiotic resistance in bacteria, and plays an important role in the evolution of bacteria that can degrade novel compounds such as human-created pesticides and in the evolution, maintenance, and transmission of virulence. It often involves temperate bacteriophages and plasmids. Genes responsible for antibiotic resistance in one species of bacteria can be transferred to another species of bacteria through various mechanisms of HGT such as transformation, transduction and conjugation, subsequently arming the antibiotic resistant genes' recipient against antibiotics. The rapid spread of antibiotic resistance genes in this manner is becoming a challenge to manage in the field of medicine. Ecological factors may also play a role in the HGT of antibiotic resistant genes.

Horizontal gene transfer is recognized as a pervasive evolutionary process that distributes genes between divergent prokaryotic lineages and can also involve eukaryotes. HGT events are thought to occur less frequently in eukaryotes than in prokaryotes. However, growing evidence indicates that HGT is relatively common among many eukaryotic species and can have an impact on adaptation to novel environments. Its study, however, is hindered by the complexity of eukaryotic genomes and the abundance of repeat-rich regions, which complicate the accurate identification and characterization of transferred genes.

It is postulated that HGT promotes the maintenance of a universal life biochemistry and, subsequently, the universality of the genetic code.

History

Griffith's experiment, reported in 1928 by Frederick Griffith, was the first experiment suggesting that bacteria are capable of transferring genetic information through a process known as transformation. Griffith's findings were followed by research in the late 1930s and early 1940s that isolated DNA as the material that communicated this genetic information.

Horizontal genetic transfer was then described in Seattle in 1951, in a paper demonstrating that the transfer of a viral gene into Corynebacterium diphtheriae created a virulent strain from a non-virulent strain, simultaneously revealing the mechanism of diphtheria (that patients could be infected with the bacteria but not have any symptoms, and then suddenly convert later or never), and giving the first example for the relevance of the lysogenic cycle. Inter-bacterial gene transfer was first described in Japan in a 1959 publication that demonstrated the transfer of antibiotic resistance between different species of bacteria. In the mid-1980s, Syvanen postulated that biologically significant lateral gene transfer has existed since the beginning of life on Earth and has been involved in shaping all of evolutionary history.

As Jian, Rivera and Lake (1999) put it: "Increasingly, studies of genes and genomes are indicating that considerable horizontal transfer has occurred between prokaryotes" (see also Lake and Rivera, 2007). The phenomenon appears to have had some significance for unicellular eukaryotes as well. As Bapteste et al. (2005) observe, "additional evidence suggests that gene transfer might also be an important evolutionary mechanism in protist evolution."

Grafting of one plant to another can transfer chloroplasts (organelles in plant cells that conduct photosynthesis), mitochondrial DNA, and the entire cell nucleus containing the genome to potentially make a new species. Some Lepidoptera (e.g. monarch butterflies and silkworms) have been genetically modified by horizontal gene transfer from the wasp bracovirus. Bites from insects in the family Reduviidae (assassin bugs) can, via a parasite, infect humans with the trypanosomal Chagas disease, which can insert its DNA into the human genome. It has been suggested that lateral gene transfer to humans from bacteria may play a role in cancer.

Aaron Richardson and Jeffrey D. Palmer state: "Horizontal gene transfer (HGT) has played a major role in bacterial evolution and is fairly common in certain unicellular eukaryotes. However, the prevalence and importance of HGT in the evolution of multicellular eukaryotes remain unclear."

Due to the increasing amount of evidence suggesting the importance of these phenomena for evolution (see below) molecular biologists such as Peter Gogarten have described horizontal gene transfer as "A New Paradigm for Biology".

Mechanisms

There are several mechanisms for horizontal gene transfer:

  • Transformation, the genetic alteration of a cell resulting from the introduction, uptake and expression of foreign genetic material (DNA or RNA). This process is relatively common in bacteria, but less so in eukaryotes. Transformation is often used in laboratories to insert novel genes into bacteria for experiments or for industrial or medical applications. See also molecular biology and biotechnology.
  • Transduction, the process in which bacterial DNA is moved from one bacterium to another by a virus (a bacteriophage, or phage).
  • Bacterial conjugation, a process that involves the transfer of DNA via a plasmid from a donor cell to a recombinant recipient cell during cell-to-cell contact.
  • Gene transfer agents, virus-like elements encoded by the host that are found in the alphaproteobacteria order Rhodobacterales.

Horizontal transposon transfer

A transposable element (TE) (also called a transposon or jumping gene) is a mobile segment of DNA that can sometimes pick up a resistance gene and insert it into a plasmid or chromosome, thereby inducing horizontal gene transfer of antibiotic resistance.

Horizontal transposon transfer (HTT) refers to the passage of pieces of DNA that are characterized by their ability to move from one locus to another between genomes by means other than parent-to-offspring inheritance. Horizontal gene transfer has long been thought to be crucial to prokaryotic evolution, but there is a growing amount of data showing that HTT is a common and widespread phenomenon in eukaryote evolution as well. On the transposable element side, spreading between genomes via horizontal transfer may be viewed as a strategy to escape purging due to purifying selection, mutational decay and/or host defense mechanisms.

HTT can occur with any type of transposable elements, but DNA transposons and LTR retroelements are more likely to be capable of HTT because both have a stable, double-stranded DNA intermediate that is thought to be sturdier than the single-stranded RNA intermediate of non-LTR retroelements, which can be highly degradable. Non-autonomous elements may be less likely to transfer horizontally compared to autonomous elements because they do not encode the proteins required for their own mobilization. The structure of these non-autonomous elements generally consists of an intronless gene encoding a transposase protein, and may or may not have a promoter sequence. Those that do not have promoter sequences encoded within the mobile region rely on adjacent host promoters for expression. Horizontal transfer is thought to play an important role in the TE life cycle. In plants, it appears that LTR retrotransposons of the Copia superfamilies, especially those with low copy numbers from the Ale and Ivana lineages, are more likely to undergo horizontal transfer between different plant species.

HTT has been shown to occur between species and across continents in both plants and animals (Ivancevic et al. 2013), though some TEs have been shown to more successfully colonize the genomes of certain species over others. Both spatial and taxonomic proximity of species has been proposed to favor HTTs in plants and animals. It is unknown how the density of a population may affect the rate of HTT events within a population, but close proximity due to parasitism and cross contamination due to crowding have been proposed to favor HTT in both plants and animals. In plants, the interaction between lianas and trees has been shown to facilitate HTT in natural ecosystems. Successful transfer of a transposable element requires delivery of DNA from donor to host cell (and to the germ line for multi-cellular organisms), followed by integration into the recipient host genome. Though the actual mechanism for the transportation of TEs from donor cells to host cells is unknown, it is established that naked DNA and RNA can circulate in bodily fluid. Many proposed vectors include arthropods, viruses, freshwater snails (Ivancevic et al. 2013), endosymbiotic bacteria, and intracellular parasitic bacteria. In some cases, even TEs facilitate transport for other TEs.

The arrival of a new TE in a host genome can have detrimental consequences because TE mobility may induce mutation. However, HTT can also be beneficial by introducing new genetic material into a genome and promoting the shuffling of genes and TE domains among hosts, which can be co-opted by the host genome to perform new functions. Moreover, transposition activity increases the TE copy number and generates chromosomal rearrangement hotspots. HTT detection is a difficult task because it is an ongoing phenomenon that is constantly changing in frequency of occurrence and composition of TEs inside host genomes. Furthermore, few species have been analyzed for HTT, making it difficult to establish patterns of HTT events between species. These issues can lead to the underestimation or overestimation of HTT events between ancestral and current eukaryotic species.

Methods of detection

A speciation event produces orthologs of a gene in the two daughter species. A horizontal gene transfer event from one species to another adds a xenolog of the gene to the receiving genome.

Horizontal gene transfer is typically inferred using bioinformatics methods, either by identifying atypical sequence signatures ("parametric" methods) or by identifying strong discrepancies between the evolutionary history of particular sequences compared to that of their hosts. The transferred gene (xenolog) found in the receiving species is more closely related to the genes of the donor species than would be expected.

Viruses

The virus called Mimivirus infects amoebae. Another virus, called Sputnik, also infects amoebae, but it cannot reproduce unless mimivirus has already infected the same cell.

Sputnik's genome reveals further insight into its biology. Although 13 of its genes show little similarity to any other known genes, three are closely related to mimivirus and mamavirus genes, perhaps cannibalized by the tiny virus as it packaged up particles sometime in its history. This suggests that the satellite virus could perform horizontal gene transfer between viruses, paralleling the way that bacteriophages ferry genes between bacteria.

Horizontal transfer is also seen between geminiviruses and tobacco plants.

Prokaryotes

Horizontal gene transfer is common among bacteria, even among very distantly related ones, and also between bacteria and archaea. This process is thought to be a significant cause of increased drug resistance when one bacterial cell acquires resistance, and the resistance genes are transferred to the other species. Transposition and horizontal gene transfer, along with strong natural selective forces have led to multi-drug resistant strains of S. aureus and many other pathogenic bacteria. Horizontal gene transfer also plays a role in the spread of virulence factors, such as exotoxins and exoenzymes, amongst bacteria. A prime example concerning the spread of exotoxins is the adaptive evolution of Shiga toxins in E. coli through horizontal gene transfer via transduction with Shigella species of bacteria. Strategies to combat certain bacterial infections by targeting these specific virulence factors and mobile genetic elements have been proposed. For example, horizontally transferred genetic elements play important roles in the virulence of E. coli, Salmonella, Streptococcus and Clostridium perfringens.

In prokaryotes, restriction-modification systems are known to provide immunity against horizontal gene transfer and in stabilizing mobile genetic elements. Genes encoding restriction modification systems have been reported to move between prokaryotic genomes within mobile genetic elements (MGE) such as plasmids, prophages, insertion sequences/transposons, integrative conjugative elements (ICE), and integrons. Still, they are more frequently a chromosomal-encoded barrier to MGE than an MGE-encoded tool for cell infection.

Lateral gene transfer via a mobile genetic element, namely the integrated conjugative element (ICE) Bs1 has been reported for its role in the global DNA damage SOS response of the gram positive Bacillus subtilis. Furthermore, it has been linked with the radiation and desiccation resistance of Bacillus pumilus SAFR-032 spores, isolated from spacecraft cleanroom facilities.

Transposon insertion elements have been reported to increase the fitness of gram-negative E. coli strains through either major transpositions or genome rearrangements, and increasing mutation rates. In a study on the effects of long-term exposure of simulated microgravity on non-pathogenic E. coli, the results showed transposon insertions occur at loci, linked to SOS stress response. When the same E. coli strain was exposed to a combination of simulated microgravity and trace (background) levels of (the broad spectrum) antibiotic (chloramphenicol), the results showed transposon-mediated rearrangements (TMRs), disrupting genes involved in bacterial adhesion, and deleting an entire segment of several genes involved with motility and chemotaxis. Both of these studies have implications for microbial growth, adaptation to and antibiotic resistance in real time space conditions.

Horizontal gene transfer is particularly active in bacterial genomes around the production of secondary or specialized metabolites. This is clearly exhibited within certain groups of bacteria including P. aeruginosa and actinomycetales, an order of Actinomycetota. Polyketide synthases (PKSs) and biosynthetic gene clusters provide modular organizations of associated genes making these bacteria well-adapted to acquire and discard helpful modular modifications via HGT. Certain areas of genes known as hotspots further increase the likelihood of horizontally transferred secondary metabolite-producing genes. The promiscuity of enzymes is a reoccurring theme in this particular theatre.

Bacterial transformation

1: Donor bacterium 2: Bacterium who will receive the gene 3: The red portion represents the gene that will be transferred. Transformation in bacteria happens in a certain environment.

Natural transformation is a bacterial adaptation for DNA transfer (HGT) that depends on the expression of numerous bacterial genes whose products are responsible for this process. In general, transformation is a complex, energy-requiring developmental process. In order for a bacterium to bind, take up and recombine exogenous DNA into its chromosome, it must become competent, that is, enter a special physiological state. Competence development in Bacillus subtilis requires expression of about 40 genes. The DNA integrated into the host chromosome is usually (but with infrequent exceptions) derived from another bacterium of the same species, and is thus homologous to the resident chromosome. The capacity for natural transformation occurs in at least 67 prokaryotic species. Competence for transformation is typically induced by high cell density and/or nutritional limitation, conditions associated with the stationary phase of bacterial growth. Competence appears to be an adaptation for DNA repair. Transformation in bacteria can be viewed as a primitive sexual process, since it involves interaction of homologous DNA from two individuals to form recombinant DNA that is passed on to succeeding generations. Although transduction is the form of HGT most commonly associated with bacteriophages, certain phages may also be able to promote transformation.

Bacterial conjugation

1: Donor bacterium cell (F+ cell) 2: Bacterium that receives the plasmid (F- cell) 3: Plasmid that will be moved to the other bacterium 4: Pilus and T4SS. Conjugation in bacteria using a sex pilus; then the bacterium that received the plasmid can go give it to other bacteria as well.
E. coli cells going through conjugation and sharing genetic information. F-pilus is reaching towards other cell.

As mentioned before, conjugation is a method of horizontal gene transfer through cell to cell contact. Through the process of conjugation, type IV Secretion Systems (T4SS) are used to passage on DNA from the donor cell to the recipient cell. These T4SS encoded within the plasmid carry other proteins and genes that help supplement the cell in conjugation. Research has shown that there are Single Binding DNA Binding proteins (SSBs) also encoded within the conjugative plasmid may help with conjugation and cell viability. This is thought to be the case because SSBs naturally are expressed to help with stabilizing single-stranded DNA (ssDNA). SSBs will also recruit other proteins like RadD or RecA expressed in events of DNA recombination, repair, and replication. Further showcasing their possible role in conjugation. Although it may help, studies have also shown for proteins like SSB to not be essential in conjugation. For example, the plasmid pCF10 from Enterococcus faecalis, a gram-positive bacterium, has a SSB like-protein called PrgE and was classified for not being required for conjugation. More work needs to be done on why proteins that bind to ssDNA are encoded into conjugative plasmids.

Conjugation in the case of microbiomes and symbioses is very important. From this process new genes are acquired that lead to increasing genetic diversity and evolution such as the acquisition of antibiotic resistance genes. Mycobacterium tuberculosis is a species that has evolved through methods like conjugation while gaining antibiotic resistance. This evolution or increase in genetic diversity is also seen in many other species. Due to this, there is a huge concern on how impactful conjugation or horizontal gene transfer can be on human health and your microbiome as pathogenic microbes can become more pathogenic. Studies have shown that even our own microbiome has a plethora of antimicrobial genes which if transferred to pathogenic microbes could be detrimental.

Conjugation in Mycobacterium smegmatis, like conjugation in E. coli, requires stable and extended contact between a donor and a recipient strain, is DNase resistant, and the transferred DNA is incorporated into the recipient chromosome by homologous recombination. However, unlike E. coli high frequency of recombination conjugation (Hfr), mycobacterial conjugation is a type of HGT that is chromosome rather than plasmid based. Furthermore, in contrast to E. coli (Hfr) conjugation, in M. smegmatis all regions of the chromosome are transferred with comparable efficiencies. Substantial blending of the parental genomes was found as a result of conjugation, and this blending was regarded as reminiscent of that seen in the meiotic products of sexual reproduction.

Archaeal DNA transfer

Haloarchaea are aerobic halophiles thought to have evolved from anaerobic methanogens. A large amount of their genome, 126 composite gene families, are derived from genetic material from bacterial genomes. This has allowed them to adapt to extremely salty environments.

The archaeon Sulfolobus solfataricus, when UV irradiated, strongly induces the formation of type IV pili which then facilitates cellular aggregation. Exposure to chemical agents that cause DNA damage also induces cellular aggregation. Other physical stressors, such as temperature shift or pH, do not induce aggregation, suggesting that DNA damage is a specific inducer of cellular aggregation.

UV-induced cellular aggregation mediates intercellular chromosomal HGT marker exchange with high frequency, and UV-induced cultures display recombination rates that exceed those of uninduced cultures by as much as three orders of magnitude. S. solfataricus cells aggregate preferentially with other cells of their own species. Frols et al. and Ajon et al. suggested that UV-inducible DNA transfer is likely an important mechanism for providing increased repair of damaged DNA via homologous recombination. This process can be regarded as a simple form of sexual interaction.

Another thermophilic species, Sulfolobus acidocaldarius, is able to undergo HGT. S. acidocaldarius can exchange and recombine chromosomal markers at temperatures up to 84 °C. UV exposure induces pili formation and cellular aggregation. Cells with the ability to aggregate have greater survival than mutants lacking pili that are unable to aggregate. The frequency of recombination is increased by DNA damage induced by UV-irradiation and by DNA damaging chemicals.

The ups operon, containing five genes, is highly induced by UV irradiation. The proteins encoded by the ups operon are employed in UV-induced pili assembly and cellular aggregation leading to intercellular DNA exchange and homologous recombination. Since this system increases the fitness of S. acidocaldarius cells after UV exposure, Wolferen et al. considered that transfer of DNA likely takes place in order to repair UV-induced DNA damages by homologous recombination.

Eukaryotes

"Sequence comparisons suggest recent horizontal transfer of many genes among diverse species including across the boundaries of phylogenetic 'domains'. Thus determining the phylogenetic history of a species can not be done conclusively by determining evolutionary trees for single genes."

Organelle to nuclear genome

Organelle to organelle

Bacteria to fungi

Bacteria to plants

  • Agrobacterium, a pathogenic bacterium that causes cells to proliferate as crown galls and proliferating roots is an example of a bacterium that can transfer genes to plants and this plays an important role in plant evolution.
  • Land plants and their close relatives, the charophycean green algae, share a set of glycosyl hydrolases. These enzymes were likely transferred from bacteria and fungi to the last common ancestor of these organisms before the origin of land plants.

Bacteria to animals

  • HhMAN1 is a gene in the genome of the coffee berry borer (Hypothenemus hampei) that resembles bacterial genes, and is thought to be transferred from bacteria in the beetle's gut.
  • oskar is an essential gene for the specification of the germline in Holometabola and its origin is through to be due to a HGT event followed by a fusion with a LOTUS domain.
  • Bdelloid rotifers currently hold the 'record' for HGT in animals with ~8% of their genes from bacterial origins. Tardigrades were thought to break the record with 17.5% HGT, but that finding was an artifact of bacterial contamination.
  • A study found the genomes of 40 animals (including 10 primates, four Caenorhabditis worms, and 12 Drosophila insects) contained genes which the researchers concluded had been transferred from bacteria and fungi by horizontal gene transfer. The researchers estimated that for some nematodes and Drosophila insects these genes had been acquired relatively recently.
  • A bacteriophage-mediated mechanism transfers genes between prokaryotes and eukaryotes. Nuclear localization signals in bacteriophage terminal proteins (TP) prime DNA replication and become covalently linked to the viral genome. The role of virus and bacteriophages in HGT in bacteria, suggests that TP-containing genomes could be a vehicle of inter-kingdom genetic information transference all throughout evolution.
  • The adzuki bean beetle has acquired genetic material from its (non-beneficial) endosymbiont Wolbachia. New examples have recently been reported demonstrating that Wolbachia bacteria represent an important potential source of genetic material in arthropods and filarial nematodes.
  • The psyllid Pachypsylla venusta has acquired genes from its current endosymbiont Carsonella, and from many of its historical endosymbionts, too.

Plant to plant

  • Striga hermonthica, a parasitic eudicot, has received a gene from sorghum (Sorghum bicolor) to its nuclear genome. The gene's functionality is unknown.
  • A gene that allowed ferns to survive in dark forests came from the hornwort, which grows in mats on streambanks or trees. The neochrome gene arrived about 180 million years ago.
  • Transfer of mRNA between host plants and heterotrophs plants in the Orobanchaceae have been directly observed. mRNA transcripts can therefore be a factor involved in the transfer and integration of foreign DNA in heterotrophs.

Plants to animals

Plant to fungus

  • Gene transfer between plants and fungi has been posited for a number of cases, including rice (Oryza sativa).
  • Evidence of gene transfer from plants was documented in the fungus Colletotrichum.
  • Plant expansin genes were transferred to fungi further enabling the fungi to infect plants.

Plant to bacteria

  • Plant expansin genes were transferred to bacteria further enabling the bacteria to infect plants.

Fungi to insects

  • Pea aphids (Acyrthosiphon pisum) contain multiple genes from fungi. Plants, fungi, and microorganisms can synthesize carotenoids, but torulene made by pea aphids is the only carotenoid known to be synthesized by an organism in the animal kingdom.

Fungi to fungi

  • The toxin α-amanitin is found in numerous, seemingly unrelated genera fungi such as Amanita, Lepiota, and Galerina. Two biosynthetic genes involved in the production of α-amanitin are P450-29 and FMO1. Phylogenetic and genetic analyses of these genes strongly indicate that they were transferred between the genera via horizontal gene transfer.
  • The ToxA protein (wheat virulence protein) included in a ~14 kb element, containing both coding and non-coding regions was transferred between different fungal wheat patogens: Parastagonospora nodorum, Pyrenophora tritici-repentis, and Bipolaris sorokiniana.
  • A large genomic element named "Wallaby," approximately 500 kb in length, was recently transferred between two Penicillium species used in cheesemaking: P. camemberti and P. roqueforti. Wallaby contains around 250 genes, including several that are thought to play a role in microbial competition.

Fungi to oomycetes

  • 4 genes from Magnaporthe grisea, the rice blast fungus, were suspected to be horizontally transferred from the genus Phytophthora, and hypothesized to play a role in the fungus evolution into a plant pathogen.

Oomycetes to fungi

  • The oomycete species Phytophthora ramorum, Phytophthora sojae, Phytophthora infestans, and Hyaloperonospora parasitica were estimated to have 33 horizontal gene transfers from fungi. The transferred genes were hypothesized to be involved in functions that facilitate plant tissues colonization, such as secreted proteins to evade plant immune response and breaking down plant cell walls.

Animals to animals

Animals to bacteria

  • The strikingly fish-like copper/zinc superoxide dismutase of Photobacterium leiognathi is most easily explained in terms of transfer of a gene from an ancestor of its fish host.

Human to protozoan

Human genome

  • One study identified approximately 100 of humans' approximately 20,000 total genes which likely resulted from horizontal gene transfer, but this number has been challenged by several researchers arguing these candidate genes for HGT are more likely the result of gene loss combined with differences in the rate of evolution.

Compounds found to promote horizontal gene transfer

Through research into the growing issue of antibiotic resistance certain compounds have been observed to promote horizontal gene transfer. Antibiotics given to bacteria at non-lethal levels have been known to be a cause of antibiotic resistance but emerging research is now showing that certain non-antibiotic pharmaceuticals (ibuprofen, naproxen, gemfibrozil, diclofenac, propranolol, etc.) also have a role in promoting antibiotic resistance through their ability to promote horizontal gene transfer (HGT) of genes responsible for antibiotic resistance. The transfer of antibiotic resistance genes (ARGs) through conjugation is significantly accelerated when donor cells with plasmids and recipient cells are introduced to each other in the presence of one of the pharmaceuticals. Non-antibiotic pharmaceuticals were also found to cause some responses in bacteria similar to those responses to antibiotics, such as increasing expression of the genes lexA, umuC, umuD and soxR involved in the bacteria's SOS response as well as other genes also expressed during exposure to antibiotics. These findings are from 2021 and due to the widespread use of non-antibiotic pharmaceuticals, more research needs to be done in order to further understanding on the issue.

Alongside non-antibiotic pharmaceuticals, other compounds relevant to antibiotic resistance have been tested such as malachite green, ethylbenzene, styrene, 2,4-dichloroaniline, trioxymethylene, o-xylene solutions, p-nitrophenol (PNP), p-aminophenol (PAP), and phenol (PhOH). It is a global concern that ARGs have been found in wastewater treatment plants Textile wastewater has been found to contain 3- to 13-fold higher abundance of mobile genetic elements than other samples of wastewater. The cause of this is the organic compounds used for textile dying (o-xylene, ethylbenzene, trioxymethylene, styrene, 2,4-dichloroaniline, and malachite green) raising the frequency of conjugative transfer when bacteria and plasmid (with donor) are introduced in the presence of these molecules. When textile wastewater combines with wastewater from domestic sewage, the ARGs present in wastewater are transferred at a higher rate due to the addition of textile dyeing compounds increasing the occurrence of HGT.

Other organic pollutants commonly found in wastewater have been the subject of similar experiments. A 2021 study used similar methods of using plasmid in a donor and mixing that with a receptor in the presence of compound in order to test horizontal gene transfer of antibiotic resistance genes but this time in the presence of phenolic compounds. Phenolic compounds are commonly found in wastewater and have been found to change functions and structures of the microbial communities during the wastewater treatment process. Additionally, HGT increases in frequency in the presence of the compounds p-nitrophenol (PNP), p-aminophenol (PAP), and phenol. These compounds result in a 2- to 9-fold increase in HGT (p-nitrophenol being on the lower side of 2-fold increases and p-aminophenol and phenol having a maximum increase of 9-fold). This increase in HGT is on average less than the compounds ibuprofen, naproxen, gemfibrozil, diclofenac, propranolol, o-xylene, ethylbenzene, trioxymethylene, styrene, 2,4-dichloroaniline, and malachite green but their increases is still significant. The study that came to this conclusion is similar to the study on horizontal gene transfer and non-antibiotic pharmaceuticals in that it was done in 2021 and leaves room for more research, specifically in the focus of the study which is activated sludge.

Heavy metals have also been found to promote conjugative transfer of antibiotic resistance genes. The paper that led to the discovery of this was done in 2017 during the emerging field of horizontal gene transfer assisting compound research. Metals assist in the spread of antibiotic resistance through both co-resistance as well as cross-resistance mechanisms. In quantities relevant to the environment, Cu(II), Ag(I), Cr(VI), and Zn(II) promote HGT from donor and receptor strains of E. coli. The presence of these metals triggered SOS response from bacterial cells and made the cells more permeable. These are the mechanisms that make even low levels of heavy metal pollution in the environment impact HGT and therefore the spread of ARGs.

Promiscuous DNA

Promiscuous DNA is a form of horizontal gene transfer that transmits genetic information across organellar barriers. Promiscuous DNA transfer has substantial evidence in its movement across the genome of numerous organisms, from movements in chloroplast to the nucleus, chloroplast to the mitochondria, and mitochondria to the nucleus.

History

In 1982, R. John Ellis defined this type of transpositional transfer mutation as "intracellular promiscuity". Ellis further explored the phenomenon of "intracellular promiscuity" through the experiments of David Stern and David Lonsdale, in which genetic transfer between chloroplasts to mitochondria was discovered, aiding in the definition and discovery of promiscuous DNA.

Mechanism

While much remains to be understood about how promiscuous DNA undergoes movement and transfer, numerous experiments have pointed to plastid sequences, ptDNA, as a key player. Plasmids, with their mobile nature and crucial role in horizontal gene transfer, are seen as a significant element in DNA that exchanges genetic information. This mobility makes ptDNA a potential donor for promiscuous DNA to traverse organellar barriers.

Types

NUMTs

NUMTs (nuclear sequences of mitochondrial) are a type of promiscuous DNA that arises from the natural transfer of mitochondria DNA (mtDNA) to the nuclear genome (nDNA). These NUMTs, with their varying frequencies, sizes, and features, contribute to the genetic diversity across all eukaryotes and, in some cases, to diseases among humans.

NUPTs

NUPTs (nuclear plastid DNA sequences) are a type of promiscuous DNA that arises from the natural transfer of ptDNA (plastid DNA) into nDNA. These fragments of ptDNA, similar to NUMTs in frequency, size, and features, also exhibit variability across species.

Artificial horizontal gene transfer

Before it is transformed, a bacterium is susceptible to antibiotics. A plasmid can be inserted when the bacteria is under stress, and be incorporated into the bacterial DNA creating antibiotic resistance. When the plasmids are prepared they are inserted into the bacterial cell by either making pores in the plasma membrane with temperature extremes and chemical treatments, or making it semi permeable through the process of electrophoresis, in which electric currents create the holes in the membrane. After conditions return to normal the holes in the membrane close and the plasmids are trapped inside the bacteria where they become part of the genetic material and their genes are expressed by the bacteria.

Genetic engineering is essentially horizontal gene transfer, albeit with synthetic expression cassettes. The Sleeping Beauty transposon system (SB) was developed as a synthetic gene transfer agent that was based on the known abilities of Tc1/mariner transposons to invade genomes of extremely diverse species. The SB system has been used to introduce genetic sequences into a wide variety of animal genomes.

In evolution

Horizontal gene transfer is a potential confounding factor in inferring phylogenetic trees based on the sequence of one gene. For example, given two distantly related bacteria that have exchanged a gene a phylogenetic tree including those species will show them to be closely related because that gene is the same even though most other genes are dissimilar. For this reason, it is often ideal to use other information to infer robust phylogenies such as the presence or absence of genes or, more commonly, to include as wide a range of genes for phylogenetic analysis as possible.

For example, the most common gene to be used for constructing phylogenetic relationships in prokaryotes is the 16S ribosomal RNA gene since its sequences tend to be conserved among members with close phylogenetic distances, but variable enough that differences can be measured. However, in recent years it has also been argued that 16s rRNA genes can also be horizontally transferred. Although this may be infrequent, the validity of 16s rRNA-constructed phylogenetic trees must be reevaluated.

Biologist Johann Peter Gogarten suggests "the original metaphor of a tree no longer fits the data from recent genome research" therefore "biologists should use the metaphor of a mosaic to describe the different histories combined in individual genomes and use the metaphor of a net to visualize the rich exchange and cooperative effects of HGT among microbes". There exist several methods to infer such phylogenetic networks.

Using single genes as phylogenetic markers, it is difficult to trace organismal phylogeny in the presence of horizontal gene transfer. Combining the simple coalescence model of cladogenesis with rare HGT horizontal gene transfer events suggest there was no single most recent common ancestor that contained all of the genes ancestral to those shared among the three domains of life. Each contemporary molecule has its own history and traces back to an individual molecule cenancestor. However, these molecular ancestors were likely to be present in different organisms at different times."

Challenge to the tree of life

Horizontal gene transfer poses a possible challenge to the concept of the last universal common ancestor (LUCA) at the root of the tree of life that was first formulated by Carl Woese, which led him to propose the Archaea as a third domain of life. Indeed, it was while examining the new three-domain model of life that horizontal gene transfer arose as a complicating issue: Archaeoglobus fulgidus was seen as an anomaly with respect to a phylogenetic tree, based upon the encoding for the enzyme HMGCoA reductase; the organism in question is a definite Archaean, with all the cell lipids and transcription machinery that are expected of an Archaean, but whose HMGCoA genes are of bacterial origin. Scientists are broadly agreed on symbiogenesis, that mitochondria in eukaryotes derived from alpha-proteobacterial cells and that chloroplasts came from ingested cyanobacteria, and other gene transfers may have affected early eukaryotes. (In contrast, multicellular eukaryotes have mechanisms to prevent horizontal gene transfer, including separated germ cells.) If there had been continued and extensive gene transfer, there would be a complex network with many ancestors, instead of a tree of life with sharply delineated lineages leading back to a LUCA. However, a LUCA can be identified, so horizontal transfers must have been relatively limited.

Other early HGTs are thought to have happened. The first common ancestor (FUCA), earliest ancestor of LUCA, had other descendants that had their own lineages. These now-extinct sister lineages of LUCA descending from FUCA are thought to have horizontally transferred some of their genes into the genome of early descendants of LUCA.

Phylogenetic information in HGT

It has been remarked that, despite the complications, the detection of horizontal gene transfers brings valuable phylogenetic and dating information.

The potential of HGT to be used for dating phylogenies has recently been confirmed.

The chromosomal organization of horizontal gene transfer

The acquisition of new genes has the potential to disorganize the other genetic elements and hinder the function of the bacterial cell, thus affecting the competitiveness of bacteria. Consequently, bacterial adaptation lies in a conflict between the advantages of acquiring beneficial genes, and the need to maintain the organization of the rest of its genome. Horizontally transferred genes are typically concentrated in only ~1% of the chromosome (in regions called hotspots). This concentration increases with genome size and with the rate of transfer. Hotspots diversify by rapid gene turnover; their chromosomal distribution depends on local contexts (neighboring core genes), and content in mobile genetic elements. Hotspots concentrate most changes in gene repertoires, reduce the trade-off between genome diversification and organization, and should be treasure troves of strain-specific adaptive genes. Most mobile genetic elements and antibiotic resistance genes are in hotspots, but many hotspots lack recognizable mobile genetic elements and exhibit frequent homologous recombination at flanking core genes. Overrepresentation of hotspots with fewer mobile genetic elements in naturally transformable bacteria suggests that homologous recombination and horizontal gene transfer are tightly linked in genome evolution.

Genes

There is evidence for historical horizontal transfer of the following genes:

Authoritarianism

From Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/Authoritarianism   Authoritarianism is a political system chara...