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Friday, November 11, 2022

Neolithic

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Neolithic

Neolithic
The Neolithic is characterized by fixed human settlements. Reconstruction of Pre-Pottery Neolithic B housing in Aşıklı Höyük, modern Turkey.
PeriodFinal period of Stone Age
Dates10,000–4,500 BC (2,200 BC in Western Europe)
Preceded byMesolithic, Epipalaeolithic
Followed byChalcolithic
Reconstruction of a Neolithic farmstead, Irish National Heritage Park. The Neolithic saw the invention of agriculture.

The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts of the world. This "Neolithic package" included the introduction of farming, domestication of animals, and change from a hunter-gatherer lifestyle to one of settlement.

It began about 12,000 years ago when farming appeared in the Epipalaeolithic Near East, and later in other parts of the world. The Neolithic lasted in the Near East until the transitional period of the Chalcolithic (Copper Age) from about 6,500 years ago (4500 BC), marked by the development of metallurgy, leading up to the Bronze Age and Iron Age.

In other places the Neolithic followed the Mesolithic (Middle Stone Age) and then lasted until later. In Ancient Egypt, the Neolithic lasted until the Protodynastic period, c. 3150 BC. In China it lasted until circa 2000 BC with the rise of the pre-Shang Erlitou culture, and in Scandinavia the Neolithic lasted until about 2000 BC. Some other parts of the world (including Oceania and some regions of the Americas) remained broadly comparable to the Neolithic stage of development until first contact.

The term Neolithic is modern, based on Greek νέος néos 'new' and λίθος líthos 'stone', literally 'New Stone Age'. The term was coined by Sir John Lubbock in 1865 as a refinement of the three-age system.

Origin

Approximate centers of origin of agriculture in the Neolithic revolution and its spread in prehistory: the Fertile Crescent (11,000 BP), the Yangtze and Yellow River basins (9,000 BP) and the New Guinea Highlands (9,000–6,000 BP), Central Mexico (5,000–4,000 BP), Northern South America (5,000–4,000 BP), sub-Saharan Africa (5,000–4,000 BP, exact location unknown), eastern North America (4,000–3,000 BP).

Following the ASPRO chronology, the Neolithic started in around 10,200 BC in the Levant, arising from the Natufian culture, when pioneering use of wild cereals evolved into early farming. The Natufian period or "proto-Neolithic" lasted from 12,500 to 9,500 BC, and is taken to overlap with the Pre-Pottery Neolithic (PPNA) of 10,200–8800 BC. As the Natufians had become dependent on wild cereals in their diet, and a sedentary way of life had begun among them, the climatic changes associated with the Younger Dryas (about 10,000 BC) are thought to have forced people to develop farming.

By 10,200–8,800 BC farming communities had arisen in the Levant and spread to Asia Minor, North Africa and North Mesopotamia. Mesopotamia is the site of the earliest developments of the Neolithic Revolution from around 10,000 BC.

Early Neolithic farming was limited to a narrow range of plants, both wild and domesticated, which included einkorn wheat, millet and spelt, and the keeping of dogs. By about 8000 BC, it included domesticated sheep and goats, cattle and pigs.

Not all of these cultural elements characteristic of the Neolithic appeared everywhere in the same order: the earliest farming societies in the Near East did not use pottery. In other parts of the world, such as Africa, South Asia and Southeast Asia, independent domestication events led to their own regionally distinctive Neolithic cultures, which arose completely independently of those in Europe and Southwest Asia. Early Japanese societies and other East Asian cultures used pottery before developing agriculture.

Periods by region

Southwest Asia

An array of Neolithic artifacts, including bracelets, axe heads, chisels, and polishing tools.

In the Middle East, cultures identified as Neolithic began appearing in the 10th millennium BC. Early development occurred in the Levant (e.g. Pre-Pottery Neolithic A and Pre-Pottery Neolithic B) and from there spread eastwards and westwards. Neolithic cultures are also attested in southeastern Anatolia and northern Mesopotamia by around 8000 BC.

Anatolian Neolithic farmers derived a significant portion of their ancestry from the Anatolian hunter-gatherers (AHG), suggesting that agriculture was adopted in site by these hunter-gatherers and not spread by demic diffusion into the region

Pre-Pottery Neolithic A

The Neolithic 1 (PPNA) period began roughly around 10,000 BC in the Levant. A temple area in southeastern Turkey at Göbekli Tepe, dated to around 9500 BC, may be regarded as the beginning of the period. This site was developed by nomadic hunter-gatherer tribes, as evidenced by the lack of permanent housing in the vicinity, and may be the oldest known human-made place of worship. At least seven stone circles, covering 25 acres (10 ha), contain limestone pillars carved with animals, insects, and birds. Stone tools were used by perhaps as many as hundreds of people to create the pillars, which might have supported roofs. Other early PPNA sites dating to around 9500–9000 BC have been found in Tell es-Sultan (ancient Jericho), Israel (notably Ain Mallaha, Nahal Oren, and Kfar HaHoresh), Gilgal in the Jordan Valley, and Byblos, Lebanon. The start of Neolithic 1 overlaps the Tahunian and Heavy Neolithic periods to some degree.

The major advance of Neolithic 1 was true farming. In the proto-Neolithic Natufian cultures, wild cereals were harvested, and perhaps early seed selection and re-seeding occurred. The grain was ground into flour. Emmer wheat was domesticated, and animals were herded and domesticated (animal husbandry and selective breeding).

In 2006, remains of figs were discovered in a house in Jericho dated to 9400 BC. The figs are of a mutant variety that cannot be pollinated by insects, and therefore the trees can only reproduce from cuttings. This evidence suggests that figs were the first cultivated crop and mark the invention of the technology of farming. This occurred centuries before the first cultivation of grains.

Settlements became more permanent, with circular houses, much like those of the Natufians, with single rooms. However, these houses were for the first time made of mudbrick. The settlement had a surrounding stone wall and perhaps a stone tower (as in Jericho). The wall served as protection from nearby groups, as protection from floods, or to keep animals penned. Some of the enclosures also suggest grain and meat storage.

Pre-Pottery Neolithic B

Female and male figurines; 9000–7000 BC; gypsum with bitumen and stone inlays; from Tell Fekheriye (Al-Hasakah Governorate of Syria); University of Chicago Oriental Institute (USA)

The Neolithic 2 (PPNB) began around 8800 BC according to the ASPRO chronology in the Levant (Jericho, West Bank). As with the PPNA dates, there are two versions from the same laboratories noted above. This system of terminology, however, is not convenient for southeast Anatolia and settlements of the middle Anatolia basin. A settlement of 3,000 inhabitants was found in the outskirts of Amman, Jordan. Considered to be one of the largest prehistoric settlements in the Near East, called 'Ain Ghazal, it was continuously inhabited from approximately 7250 BC to approximately 5000 BC.

Settlements have rectangular mud-brick houses where the family lived together in single or multiple rooms. Burial findings suggest an ancestor cult where people preserved skulls of the dead, which were plastered with mud to make facial features. The rest of the corpse could have been left outside the settlement to decay until only the bones were left, then the bones were buried inside the settlement underneath the floor or between houses.

Pre-Pottery Neolithic C

Work at the site of 'Ain Ghazal in Jordan has indicated a later Pre-Pottery Neolithic C period. Juris Zarins has proposed that a Circum Arabian Nomadic Pastoral Complex developed in the period from the climatic crisis of 6200 BC, partly as a result of an increasing emphasis in PPNB cultures upon domesticated animals, and a fusion with Harifian hunter gatherers in the Southern Levant, with affiliate connections with the cultures of Fayyum and the Eastern Desert of Egypt. Cultures practicing this lifestyle spread down the Red Sea shoreline and moved east from Syria into southern Iraq.

Late Neolithic

The Late Neolithic began around 6,400 BC in the Fertile Crescent. By then distinctive cultures emerged, with pottery like the Halafian (Turkey, Syria, Northern Mesopotamia) and Ubaid (Southern Mesopotamia). This period has been further divided into PNA (Pottery Neolithic A) and PNB (Pottery Neolithic B) at some sites.

The Chalcolithic (Stone-Bronze) period began about 4500 BC, then the Bronze Age began about 3500 BC, replacing the Neolithic cultures.

Fertile Crescent

'Ain Ghazal Statues, found at 'Ain Ghazal in Jordan, are considered to be one of the earliest large-scale representations of the human form dating back to around 7250 BC.
 
Neolithic wall painting from Tell Bouqras at the Deir ez-Zor Museum, Syria

Around 10,000 BC the first fully developed Neolithic cultures belonging to the phase Pre-Pottery Neolithic A (PPNA) appeared in the Fertile Crescent. Around 10,700–9400 BC a settlement was established in Tell Qaramel, 10 miles (16 km) north of Aleppo. The settlement included two temples dating to 9650 BC. Around 9000 BC during the PPNA, one of the world's first towns, Jericho, appeared in the Levant. It was surrounded by a stone wall, may have contained a population of up to 2,000–3,000 people, and contained a massive stone tower. Around 6400 BC the Halaf culture appeared in Syria and Northern Mesopotamia.

In 1981, a team of researchers from the Maison de l'Orient et de la Méditerranée, including Jacques Cauvin and Oliver Aurenche, divided Near East Neolithic chronology into ten periods (0 to 9) based on social, economic and cultural characteristics. In 2002, Danielle Stordeur and Frédéric Abbès advanced this system with a division into five periods.

  1. Natufian between 12,000 and 10,200 BC,
  2. Khiamian between 10,200 and 8800 BC, PPNA: Sultanian (Jericho), Mureybetian,
  3. Early PPNB (PPNB ancien) between 8800 and 7600 BC, middle PPNB (PPNB moyen) between 7600 and 6900 BC,
  4. Late PPNB (PPNB récent) between 7500 and 7000 BC,
  5. A PPNB (sometimes called PPNC) transitional stage (PPNB final) in which Halaf and dark faced burnished ware begin to emerge between 6900 and 6400 BC.

They also advanced the idea of a transitional stage between the PPNA and PPNB between 8800 and 8600 BC at sites like Jerf el Ahmar and Tell Aswad.

Southern Mesopotamia

Alluvial plains (Sumer/Elam). Low rainfall makes irrigation systems necessary. Ubaid culture from 6,900 BC.

North Africa

Algerian cave paintings depicting hunting scenes

Domestication of sheep and goats reached Egypt from the Near East possibly as early as 6000 BC. Graeme Barker states "The first indisputable evidence for domestic plants and animals in the Nile valley is not until the early fifth millennium BC in northern Egypt and a thousand years later further south, in both cases as part of strategies that still relied heavily on fishing, hunting, and the gathering of wild plants" and suggests that these subsistence changes were not due to farmers migrating from the Near East but was an indigenous development, with cereals either indigenous or obtained through exchange. Other scholars argue that the primary stimulus for agriculture and domesticated animals (as well as mud-brick architecture and other Neolithic cultural features) in Egypt was from the Middle East.

Sub-Saharan Africa

The Pastoral Neolithic refers to a period in Africa's prehistory marking the beginning of food production on the continent following the Later Stone Age. In contrast to the Neolithic in other parts of the world, which saw the development of farming societies, the first form of African food production was mobile pastoralism, or ways of life centered on the herding and management of livestock. The term "Pastoral Neolithic" is used most often by archaeologists to describe early pastoralist periods in the Sahara, as well as in eastern Africa.

The Savanna Pastoral Neolithic or SPN (formerly known as the Stone Bowl Culture) is a collection of ancient societies that appeared in the Rift Valley of East Africa and surrounding areas during a time period known as the Pastoral Neolithic. They were South Cushitic speaking pastoralists, who tended to bury their dead in cairns whilst their toolkit was characterized by stone bowls, pestles, grindstones and earthenware pots. Through archaeology, historical linguistics and archaeogenetics, they conventionally have been identified with the area's first Afroasiatic-speaking settlers. Archaeological dating of livestock bones and burial cairns has also established the cultural complex as the earliest center of pastoralism and stone construction in the region.

Europe

Female figure from Tumba Madžari, North Macedonia
 
Map showing distribution of some of the main culture complexes in Neolithic Europe, c. 3500 BC
 
Skara Brae, Scotland. Evidence of home furnishings (shelves)

In southeast Europe agrarian societies first appeared in the 7th millennium BC, attested by one of the earliest farming sites of Europe, discovered in Vashtëmi, southeastern Albania and dating back to 6500 BC. In most of Western Europe in followed over the next two thousand years, but in some parts of Northwest Europe it is much later, lasting just under 3,000 years from c. 4500 BC–1700 BC. Recent advances in archaeogenetics have confirmed that the spread of agriculture from the Middle East to Europe was strongly correlated with the migration of early farmers from Anatolia about 9,000 years ago, and was not just a cultural exchange.

Anthropomorphic figurines have been found in the Balkans from 6000 BC, and in Central Europe by around 5800 BC (La Hoguette). Among the earliest cultural complexes of this area are the Sesklo culture in Thessaly, which later expanded in the Balkans giving rise to Starčevo-Körös (Cris), Linearbandkeramik, and Vinča. Through a combination of cultural diffusion and migration of peoples, the Neolithic traditions spread west and northwards to reach northwestern Europe by around 4500 BC. The Vinča culture may have created the earliest system of writing, the Vinča signs, though archaeologist Shan Winn believes they most likely represented pictograms and ideograms rather than a truly developed form of writing.

The Cucuteni-Trypillian culture built enormous settlements in Romania, Moldova and Ukraine from 5300 to 2300 BC. The megalithic temple complexes of Ġgantija on the Mediterranean island of Gozo (in the Maltese archipelago) and of Mnajdra (Malta) are notable for their gigantic Neolithic structures, the oldest of which date back to around 3600 BC. The Hypogeum of Ħal-Saflieni, Paola, Malta, is a subterranean structure excavated around 2500 BC; originally a sanctuary, it became a necropolis, the only prehistoric underground temple in the world, and shows a degree of artistry in stone sculpture unique in prehistory to the Maltese islands. After 2500 BC, these islands were depopulated for several decades until the arrival of a new influx of Bronze Age immigrants, a culture that cremated its dead and introduced smaller megalithic structures called dolmens to Malta. In most cases there are small chambers here, with the cover made of a large slab placed on upright stones. They are claimed to belong to a population different from that which built the previous megalithic temples. It is presumed the population arrived from Sicily because of the similarity of Maltese dolmens to some small constructions found there.

With some exceptions, population levels rose rapidly at the beginning of the Neolithic until they reached the carrying capacity. This was followed by a population crash of "enormous magnitude" after 5000 BC, with levels remaining low during the next 1,500 years. Populations began to rise after 3500 BCE, with further dips and rises occurring between 3000 and 2500 BC but varying in date between regions. Around this time is the Neolithic decline, when populations collapsed across most of Europe, possibly caused by climatic conditions, plague, or mass migration.

South and East Asia

Settled life, encompassing the transition from foraging to farming and pastoralism, began in South Asia in the region of Balochistan, Pakistan, around 7,000 BC. At the site of Mehrgarh, Balochistan, presence can be documented of the domestication of wheat and barley, rapidly followed by that of goats, sheep, and cattle. In April 2006, it was announced in the scientific journal Nature that the oldest (and first early Neolithic) evidence for the drilling of teeth in vivo (using bow drills and flint tips) was found in Mehrgarh.

In South India, the Neolithic began by 6500 BC and lasted until around 1400 BC when the Megalithic transition period began. South Indian Neolithic is characterized by Ash mounds from 2500 BC in Karnataka region, expanded later to Tamil Nadu.

Neolithic artefacts from China

In East Asia, the earliest sites include the Nanzhuangtou culture around 9500–9000 BC, Pengtoushan culture around 7500–6100 BC, and Peiligang culture around 7000–5000 BC. The prehistoric Beifudi site near Yixian in Hebei Province, China, contains relics of a culture contemporaneous with the Cishan and Xinglongwa cultures of about 6000–5000 BC, Neolithic cultures east of the Taihang Mountains, filling in an archaeological gap between the two Northern Chinese cultures. The total excavated area is more than 1,200 square yards (1,000 m2; 0.10 ha), and the collection of Neolithic findings at the site encompasses two phases. Between 3000 and 1900 BC, the Longshan culture existed in the middle and lower Yellow River valley areas of northern China. Towards the end of the 3rd millennium BC, the population decreased sharply in most of the region and many of the larger centres were abandoned, possibly due to environmental change linked to the end of the Holocene Climatic Optimum.

The 'Neolithic' (defined in this paragraph as using polished stone implements) remains a living tradition in small and extremely remote and inaccessible pockets of West Papua (Indonesian New Guinea). Polished stone adze and axes are used in the present day (as of 2008) in areas where the availability of metal implements is limited. This is likely to cease altogether in the next few years as the older generation die off and steel blades and chainsaws prevail.

In 2012, news was released about a new farming site discovered in Munam-ri, Goseong, Gangwon Province, South Korea, which may be the earliest farmland known to date in east Asia. "No remains of an agricultural field from the Neolithic period have been found in any East Asian country before, the institute said, adding that the discovery reveals that the history of agricultural cultivation at least began during the period on the Korean Peninsula". The farm was dated between 3600 and 3000 BC. Pottery, stone projectile points, and possible houses were also found. "In 2002, researchers discovered prehistoric earthenware, jade earrings, among other items in the area". The research team will perform accelerator mass spectrometry (AMS) dating to retrieve a more precise date for the site.

The Americas

In Mesoamerica, a similar set of events (i.e., crop domestication and sedentary lifestyles) occurred by around 4500 BC, but possibly as early as 11,000–10,000 BC. These cultures are usually not referred to as belonging to the Neolithic; in America different terms are used such as Formative stage instead of mid-late Neolithic, Archaic Era instead of Early Neolithic, and Paleo-Indian for the preceding period.

The Formative stage is equivalent to the Neolithic Revolution period in Europe, Asia, and Africa. In the southwestern United States it occurred from 500 to 1200 AD when there was a dramatic increase in population and development of large villages supported by agriculture based on dryland farming of maize, and later, beans, squash, and domesticated turkeys. During this period the bow and arrow and ceramic pottery were also introduced. In later periods cities of considerable size developed, and some metallurgy by 700 BC.

Australia

Australia, in contrast to New Guinea, has generally been held not to have had a Neolithic period, with a hunter-gatherer lifestyle continuing until the arrival of Europeans. This view can be challenged in terms of the definition of agriculture, but "Neolithic" remains a rarely used and not very useful concept in discussing Australian prehistory.

Cultural characteristics

Social organization

Model of a Linear Pottery culture settlement, showing longhouses, circular enclosures, and fields
 
Anthropomorphic Neolithic ceramic figurine

During most of the Neolithic age of Eurasia, people lived in small tribes composed of multiple bands or lineages. There is little scientific evidence of developed social stratification in most Neolithic societies; social stratification is more associated with the later Bronze Age. Although some late Eurasian Neolithic societies formed complex stratified chiefdoms or even states, generally states evolved in Eurasia only with the rise of metallurgy, and most Neolithic societies on the whole were relatively simple and egalitarian. Beyond Eurasia, however, states were formed during the local Neolithic in three areas, namely in the Preceramic Andes with the Norte Chico Civilization, Formative Mesoamerica and Ancient Hawaiʻi. However, most Neolithic societies were noticeably more hierarchical than the Upper Paleolithic cultures that preceded them and hunter-gatherer cultures in general.

Clay human figurine (Fertility goddess) Tappeh Sarab, Kermanshah c.7000-6100 BC, National Museum of Iran

The domestication of large animals (c. 8000 BC) resulted in a dramatic increase in social inequality in most of the areas where it occurred; New Guinea being a notable exception. Possession of livestock allowed competition between households and resulted in inherited inequalities of wealth. Neolithic pastoralists who controlled large herds gradually acquired more livestock, and this made economic inequalities more pronounced. However, evidence of social inequality is still disputed, as settlements such as Catal Huyuk reveal a striking lack of difference in the size of homes and burial sites, suggesting a more egalitarian society with no evidence of the concept of capital, although some homes do appear slightly larger or more elaborately decorated than others.

Families and households were still largely independent economically, and the household was probably the center of life. However, excavations in Central Europe have revealed that early Neolithic Linear Ceramic cultures ("Linearbandkeramik") were building large arrangements of circular ditches between 4800 and 4600 BC. These structures (and their later counterparts such as causewayed enclosures, burial mounds, and henge) required considerable time and labour to construct, which suggests that some influential individuals were able to organise and direct human labour – though non-hierarchical and voluntary work remain possibilities.

There is a large body of evidence for fortified settlements at Linearbandkeramik sites along the Rhine, as at least some villages were fortified for some time with a palisade and an outer ditch.Settlements with palisades and weapon-traumatized bones, such as those found at the Talheim Death Pit, have been discovered and demonstrate that "...systematic violence between groups" and warfare was probably much more common during the Neolithic than in the preceding Paleolithic period. This supplanted an earlier view of the Linear Pottery Culture as living a "peaceful, unfortified lifestyle".

Control of labour and inter-group conflict is characteristic of tribal groups with social rank that are headed by a charismatic individual – either a 'big man' or a proto-chief – functioning as a lineage-group head. Whether a non-hierarchical system of organization existed is debatable, and there is no evidence that explicitly suggests that Neolithic societies functioned under any dominating class or individual, as was the case in the chiefdoms of the European Early Bronze Age. Possible exceptions to this include Iraq during the Ubaid period and England beginning in the Early Neolithic (4100-3000 BC).Theories to explain the apparent implied egalitarianism of Neolithic (and Paleolithic) societies have arisen, notably the Marxist concept of primitive communism.

Shelter and sedentism

Reconstruction of Neolithic house in Tuzla, Bosnia and Herzegovina

The shelter of the early people changed dramatically from the Upper Paleolithic to the Neolithic era. In the Paleolithic, people did not normally live in permanent constructions. In the Neolithic, mud brick houses started appearing that were coated with plaster. The growth of agriculture made permanent houses possible. Doorways were made on the roof, with ladders positioned both on the inside and outside of the houses. The roof was supported by beams from the inside. The rough ground was covered by platforms, mats, and skins on which residents slept. Stilt-house settlements were common in the Alpine and Pianura Padana (Terramare) region. Remains have been found in the Ljubljana Marsh in Slovenia and at the Mondsee and Attersee lakes in Upper Austria, for example.

Agriculture

Food and cooking items retrieved at a European Neolithic site: millstones, charred bread, grains and small apples, a clay cooking pot, and containers made of antlers and wood

A significant and far-reaching shift in human subsistence and lifestyle was to be brought about in areas where crop farming and cultivation were first developed: the previous reliance on an essentially nomadic hunter-gatherer subsistence technique or pastoral transhumance was at first supplemented, and then increasingly replaced by, a reliance upon the foods produced from cultivated lands. These developments are also believed to have greatly encouraged the growth of settlements, since it may be supposed that the increased need to spend more time and labor in tending crop fields required more localized dwellings. This trend would continue into the Bronze Age, eventually giving rise to permanently settled farming towns, and later cities and states whose larger populations could be sustained by the increased productivity from cultivated lands.

The profound differences in human interactions and subsistence methods associated with the onset of early agricultural practices in the Neolithic have been called the Neolithic Revolution, a term coined in the 1920s by the Australian archaeologist Vere Gordon Childe.

One potential benefit of the development and increasing sophistication of farming technology was the possibility of producing surplus crop yields, in other words, food supplies in excess of the immediate needs of the community. Surpluses could be stored for later use, or possibly traded for other necessities or luxuries. Agricultural life afforded securities that nomadic life could not, and sedentary farming populations grew faster than nomadic.

However, early farmers were also adversely affected in times of famine, such as may be caused by drought or pests. In instances where agriculture had become the predominant way of life, the sensitivity to these shortages could be particularly acute, affecting agrarian populations to an extent that otherwise may not have been routinely experienced by prior hunter-gatherer communities.[74] Nevertheless, agrarian communities generally proved successful, and their growth and the expansion of territory under cultivation continued.

Another significant change undergone by many of these newly agrarian communities was one of diet. Pre-agrarian diets varied by region, season, available local plant and animal resources and degree of pastoralism and hunting. Post-agrarian diet was restricted to a limited package of successfully cultivated cereal grains, plants and to a variable extent domesticated animals and animal products. Supplementation of diet by hunting and gathering was to variable degrees precluded by the increase in population above the carrying capacity of the land and a high sedentary local population concentration. In some cultures, there would have been a significant shift toward increased starch and plant protein. The relative nutritional benefits and drawbacks of these dietary changes and their overall impact on early societal development are still debated.

In addition, increased population density, decreased population mobility, increased continuous proximity to domesticated animals, and continuous occupation of comparatively population-dense sites would have altered sanitation needs and patterns of disease.

Lithic technology

The identifying characteristic of Neolithic technology is the use of polished or ground stone tools, in contrast to the flaked stone tools used during the Paleolithic era.

Neolithic people were skilled farmers, manufacturing a range of tools necessary for the tending, harvesting and processing of crops (such as sickle blades and grinding stones) and food production (e.g. pottery, bone implements). They were also skilled manufacturers of a range of other types of stone tools and ornaments, including projectile points, beads, and statuettes. But what allowed forest clearance on a large scale was the polished stone axe above all other tools. Together with the adze, fashioning wood for shelter, structures and canoes for example, this enabled them to exploit their newly won farmland.

Neolithic peoples in the Levant, Anatolia, Syria, northern Mesopotamia and Central Asia were also accomplished builders, utilizing mud-brick to construct houses and villages. At Çatalhöyük, houses were plastered and painted with elaborate scenes of humans and animals. In Europe, long houses built from wattle and daub were constructed. Elaborate tombs were built for the dead. These tombs are particularly numerous in Ireland, where there are many thousand still in existence. Neolithic people in the British Isles built long barrows and chamber tombs for their dead and causewayed camps, henges, flint mines and cursus monuments. It was also important to figure out ways of preserving food for future months, such as fashioning relatively airtight containers, and using substances like salt as preservatives.

The peoples of the Americas and the Pacific mostly retained the Neolithic level of tool technology until the time of European contact. Exceptions include copper hatchets and spearheads in the Great Lakes region.

Clothing

Most clothing appears to have been made of animal skins, as indicated by finds of large numbers of bone and antler pins that are ideal for fastening leather. Wool cloth and linen might have become available during the later Neolithic, as suggested by finds of perforated stones that (depending on size) may have served as spindle whorls or loom weights.

List of early settlements

Reconstruction of a Cucuteni-Trypillian hut, in the Tripillian Museum, Ukraine
 
archaeological site of Çatalhöyük in the Konya Plain in Turkey

Neolithic human settlements include:

name location early date (BC) late date (BC) comments
Tell Qaramel Syria 10,700 9400
Franchthi Cave Greece 10,000
reoccupied between 7500 and 6000 BC
Göbekli Tepe Turkey 9600 8000
Nanzhuangtou Hebei, China 9500 9000
Byblos Lebanon 8800 7000
Jericho (Tell es-Sultan) West Bank 9500
arising from the earlier Epipaleolithic Natufian culture
Pulli settlement Estonia 8500 5000 oldest known settlement of Kunda culture
Aşıklı Höyük Central Anatolia, Turkey, an Aceramic Neolithic period settlement 8200 7400 correlating with the E/MPPNB in the Levant
Nevali Cori Turkey 8000

Bhirrana India 7600 7200 Hakra ware
Pengtoushan culture China 7500 6100 rice residues were carbon-14 dated to 8200–7800 BC
Çatalhöyük Turkey 7500 5700
Mentesh Tepe and Kamiltepe Azerbaijan 7000 3000
'Ain Ghazal Jordan 7250 5000
Chogha Bonut Iran 7200

Jhusi India 7100

Motza Israel 7000

Ganj Dareh Iran 7000

Lahuradewa India 7000 
presence of rice cultivation, ceramics etc.
Jiahu China 7000 5800
Knossos Crete 7000

Khirokitia Cyprus 7000 4000
Mehrgarh Pakistan 7000 5500 aceramic but elaborate culture including mud brick, houses, agriculture etc.
Sesklo Greece 6850
with a 660-year margin of error
Horton Plains Sri Lanka 6700
cultivation of oats and barley as early as 11,000 BC
Porodin North Macedonia 6500

Padah-Lin Caves Burma 6000

Petnica Serbia 6000

Stara Zagora Bulgaria 5500

Cucuteni-Trypillian culture Ukraine, Moldova and Romania 5500 2750
Tell Zeidan northern Syria 5500 4000
Tabon Cave Complex Quezon, Palawan, Philippines 5000 2000
Hemudu culture, large-scale rice plantation China 5000 4500
The Megalithic Temples of Malta Malta 3600

Knap of Howar and Skara Brae Orkney, Scotland 3500 3100
Brú na Bóinne Ireland 3500

Lough Gur Ireland 3000

Shengavit Settlement Armenia 3000 2200
Norte Chico civilization, 30 aceramic Neolithic period settlements northern coastal Peru 3000 1700
Tichit Neolithic village on the Tagant Plateau central southern Mauritania 2000 500
Oaxaca, state Southwestern Mexico 2000
by 2000 BC Neolithic sedentary villages had been established in the Central Valleys region of this state.
Lajia China 2000

Mumun pottery period Korean Peninsula 1800 1500
Neolithic revolution Japan 500 300

The world's oldest known engineered roadway, the Post Track in England, dates from 3838 BC and the world's oldest freestanding structure is the Neolithic temple of Ġgantija in Gozo, Malta.

List of cultures and sites

Note: Dates are very approximate, and are only given for a rough estimate; consult each culture for specific time periods.

Early Neolithic
Periodization: The Levant: 9500–8000 BC; Europe: 5000–4000 BC; Elsewhere: varies greatly, depending on region.

Middle Neolithic
Periodization: The Levant: 8000–6000 BC; Europe: 4000–3500 BC; Elsewhere: varies greatly, depending on region.

Later Neolithic
Periodization: 6500–4500 BC; Europe: 3500–3000 BC; Elsewhere: varies greatly, depending on region.

Chalcolithic

Periodization: Near East: 4500–3300 BC; Europe: 3000–1700 BC; Elsewhere: varies greatly, depending on region. In the Americas, the Eneolithic ended as late as the 19th century AD for some peoples.

Inbreeding

From Wikipedia, the free encyclopedia
 
Common fruit fly females prefer to mate with their own brothers over unrelated males.

Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genetic disorders and other consequences that may arise from expression of deleterious or recessive traits resulting from incestuous sexual relationships and consanguinity. Animals avoid incest only rarely.

Inbreeding results in homozygosity, which can increase the chances of offspring being affected by recessive traits. In extreme cases, this usually leads to at least temporarily decreased biological fitness of a population (called inbreeding depression), which is its ability to survive and reproduce. An individual who inherits such deleterious traits is colloquially referred to as inbred. The avoidance of expression of such deleterious recessive alleles caused by inbreeding, via inbreeding avoidance mechanisms, is the main selective reason for outcrossing. Crossbreeding between populations sometimes has positive effects on fitness-related traits, but also sometimes leads to negative effects known as outbreeding depression. However, increased homozygosity increases probability of fixing beneficial alleles and also slightly decreases probability of fixing deleterious alleles in population. Inbreeding can result in purging of deleterious alleles from a population through purifying selection.

Inbreeding is a technique used in selective breeding. For example, in livestock breeding, breeders may use inbreeding when trying to establish a new and desirable trait in the stock and for producing distinct families within a breed, but will need to watch for undesirable characteristics in offspring, which can then be eliminated through further selective breeding or culling. Inbreeding also helps to ascertain the type of gene action affecting a trait. Inbreeding is also used to reveal deleterious recessive alleles, which can then be eliminated through assortative breeding or through culling. In plant breeding, inbred lines are used as stocks for the creation of hybrid lines to make use of the effects of heterosis. Inbreeding in plants also occurs naturally in the form of self-pollination.

Inbreeding can significantly influence gene expression which can prevent inbreeding depression.

Overview

Offspring of biologically related persons are subject to the possible effects of inbreeding, such as congenital birth defects. The chances of such disorders are increased when the biological parents are more closely related. This is because such pairings have a 25% probability of producing homozygous zygotes, resulting in offspring with two recessive alleles, which can produce disorders when these alleles are deleterious. Because most recessive alleles are rare in populations, it is unlikely that two unrelated marriage partners will both be carriers of the same deleterious allele; however, because close relatives share a large fraction of their alleles, the probability that any such deleterious allele is inherited from the common ancestor through both parents is increased dramatically. For each homozygous recessive individual formed there is an equal chance of producing a homozygous dominant individual — one completely devoid of the harmful allele. Contrary to common belief, inbreeding does not in itself alter allele frequencies, but rather increases the relative proportion of homozygotes to heterozygotes; however, because the increased proportion of deleterious homozygotes exposes the allele to natural selection, in the long run its frequency decreases more rapidly in inbred populations. In the short term, incestuous reproduction is expected to increase the number of spontaneous abortions of zygotes, perinatal deaths, and postnatal offspring with birth defects. The advantages of inbreeding may be the result of a tendency to preserve the structures of alleles interacting at different loci that have been adapted together by a common selective history.

Malformations or harmful traits can stay within a population due to a high homozygosity rate, and this will cause a population to become fixed for certain traits, like having too many bones in an area, like the vertebral column of wolves on Isle Royale or having cranial abnormalities, such as in Northern elephant seals, where their cranial bone length in the lower mandibular tooth row has changed. Having a high homozygosity rate is problematic for a population because it will unmask recessive deleterious alleles generated by mutations, reduce heterozygote advantage, and it is detrimental to the survival of small, endangered animal populations. When deleterious recessive alleles are unmasked due to the increased homozygosity generated by inbreeding, this can cause inbreeding depression.

There may also be other deleterious effects besides those caused by recessive diseases. Thus, similar immune systems may be more vulnerable to infectious diseases (see Major histocompatibility complex and sexual selection).

Inbreeding history of the population should also be considered when discussing the variation in the severity of inbreeding depression between and within species. With persistent inbreeding, there is evidence that shows that inbreeding depression becomes less severe. This is associated with the unmasking and elimination of severely deleterious recessive alleles. However, inbreeding depression is not a temporary phenomenon because this elimination of deleterious recessive alleles will never be complete. Eliminating slightly deleterious mutations through inbreeding under moderate selection is not as effective. Fixation of alleles most likely occurs through Muller's ratchet, when an asexual population's genome accumulates deleterious mutations that are irreversible.

Despite all its disadvantages, inbreeding can also have a variety of advantages, such as ensuring a child produced from the mating contains, and will pass on, a higher percentage of its mother/father's genetics, reducing the recombination load, and allowing the expression of recessive advantageous phenotypes. Some species with a Haplodiploidy mating system depend on the ability to produce sons to mate with as a means of ensuring a mate can be found if no other male is available. It has been proposed that under circumstances when the advantages of inbreeding outweigh the disadvantages, preferential breeding within small groups could be promoted, potentially leading to speciation.

Genetic disorders

Autosomal recessive disorders occur in individuals who have two copies of an allele for a particular recessive genetic mutation. Except in certain rare circumstances, such as new mutations or uniparental disomy, both parents of an individual with such a disorder will be carriers of the gene. These carriers do not display any signs of the mutation and may be unaware that they carry the mutated gene. Since relatives share a higher proportion of their genes than do unrelated people, it is more likely that related parents will both be carriers of the same recessive allele, and therefore their children are at a higher risk of inheriting an autosomal recessive genetic disorder. The extent to which the risk increases depends on the degree of genetic relationship between the parents; the risk is greater when the parents are close relatives and lower for relationships between more distant relatives, such as second cousins, though still greater than for the general population.

Children of parent-child or sibling-sibling unions are at an increased risk compared to cousin-cousin unions. Inbreeding may result in a greater than expected phenotypic expression of deleterious recessive alleles within a population. As a result, first-generation inbred individuals are more likely to show physical and health defects, including:

The isolation of a small population for a period of time can lead to inbreeding within that population, resulting in increased genetic relatedness between breeding individuals. Inbreeding depression can also occur in a large population if individuals tend to mate with their relatives, instead of mating randomly.

Due to higher prenatal and postnatal mortality rates, some individuals in the first generation of inbreeding will not live on to reproduce. Over time, with isolation, such as a population bottleneck caused by purposeful (assortative) breeding or natural environmental factors, the deleterious inherited traits are culled.

Island species are often very inbred, as their isolation from the larger group on a mainland allows natural selection to work on their population. This type of isolation may result in the formation of race or even speciation, as the inbreeding first removes many deleterious genes, and permits the expression of genes that allow a population to adapt to an ecosystem. As the adaptation becomes more pronounced, the new species or race radiates from its entrance into the new space, or dies out if it cannot adapt and, most importantly, reproduce.

The reduced genetic diversity, for example due to a bottleneck will unavoidably increase inbreeding for the entire population. This may mean that a species may not be able to adapt to changes in environmental conditions. Each individual will have similar immune systems, as immune systems are genetically based. When a species becomes endangered, the population may fall below a minimum whereby the forced interbreeding between the remaining animals will result in extinction.

Natural breedings include inbreeding by necessity, and most animals only migrate when necessary. In many cases, the closest available mate is a mother, sister, grandmother, father, brother, or grandfather. In all cases, the environment presents stresses to remove from the population those individuals who cannot survive because of illness.

There was an assumption that wild populations do not inbreed; this is not what is observed in some cases in the wild. However, in species such as horses, animals in wild or feral conditions often drive off the young of both sexes, thought to be a mechanism by which the species instinctively avoids some of the genetic consequences of inbreeding. In general, many mammal species, including humanity's closest primate relatives, avoid close inbreeding possibly due to the deleterious effects.

Examples

Although there are several examples of inbred populations of wild animals, the negative consequences of this inbreeding are poorly documented. In the South American sea lion, there was concern that recent population crashes would reduce genetic diversity. Historical analysis indicated that a population expansion from just two matrilineal lines was responsible for most of the individuals within the population. Even so, the diversity within the lines allowed great variation in the gene pool that may help to protect the South American sea lion from extinction.

Heterozygous

In lions, prides are often followed by related males in bachelor groups. When the dominant male is killed or driven off by one of these bachelors, a father may be replaced by his son. There is no mechanism for preventing inbreeding or to ensure outcrossing. In the prides, most lionesses are related to one another. If there is more than one dominant male, the group of alpha males are usually related. Two lines are then being "line bred". Also, in some populations, such as the Crater lions, it is known that a population bottleneck has occurred. Researchers found far greater genetic heterozygosity than expected. In fact, predators are known for low genetic variance, along with most of the top portion of the trophic levels of an ecosystem. Additionally, the alpha males of two neighboring prides can be from the same litter; one brother may come to acquire leadership over another's pride, and subsequently mate with his 'nieces' or cousins. However, killing another male's cubs, upon the takeover, allows the new selected gene complement of the incoming alpha male to prevail over the previous male. There are genetic assays being scheduled for lions to determine their genetic diversity. The preliminary studies show results inconsistent with the outcrossing paradigm based on individual environments of the studied groups.

In Central California, sea otters were thought to have been driven to extinction due to over hunting, until a small colony was discovered in the Point Sur region in the 1930s. Since then, the population has grown and spread along the central Californian coast to around 2,000 individuals, a level that has remained stable for over a decade. Population growth is limited by the fact that all Californian sea otters are descended from the isolated colony, resulting in inbreeding.

Cheetahs are another example of inbreeding. Thousands of years ago, the cheetah went through a population bottleneck that reduced its population dramatically so the animals that are alive today are all related to one another. A consequence from inbreeding for this species has been high juvenile mortality, low fecundity, and poor breeding success.

In a study on an island population of song sparrows, individuals that were inbred showed significantly lower survival rates than outbred individuals during a severe winter weather related population crash. These studies show that inbreeding depression and ecological factors have an influence on survival.

Measures

A measure of inbreeding of an individual A is the probability F(A) that both alleles in one locus are derived from the same allele in an ancestor. These two identical alleles that are both derived from a common ancestor are said to be identical by descent. This probability F(A) is called the "coefficient of inbreeding".

Another useful measure that describes the extent to which two individuals are related (say individuals A and B) is their coancestry coefficient f(A,B), which gives the probability that one randomly selected allele from A and another randomly selected allele from B are identical by descent. This is also denoted as the kinship coefficient between A and B.

A particular case is the self-coancestry of individual A with itself, f(A,A), which is the probability that taking one random allele from A and then, independently and with replacement, another random allele also from A, both are identical by descent. Since they can be identical by descent by sampling the same allele or by sampling both alleles that happen to be identical by descent, we have f(A,A) = 1/2 + F(A)/2.

Both the inbreeding and the coancestry coefficients can be defined for specific individuals or as average population values. They can be computed from genealogies or estimated from the population size and its breeding properties, but all methods assume no selection and are limited to neutral alleles.

There are several methods to compute this percentage. The two main ways are the path method and the tabular method.

Typical coancestries between relatives are as follows:

  • Father/daughter or mother/son → 25% (14)
  • Brother/sister → 25% (14)
  • Grandfather/granddaughter or grandmother/grandson → 12.5% (18)
  • Half-brother/half-sister, Double cousins → 12.5% (18)
  • Uncle/niece or aunt/nephew → 12.5% (18)
  • Great-grandfather/great-granddaughter or great-grandmother/great-grandson → 6.25% (116)
  • Half-uncle/niece or half-aunt/nephew → 6.25% (116)
  • First cousins → 6.25% (116)

Animals

Wild animals

Few studies have found evidence of regular incest avoidance in mammals, but banded mongooses are an exception.
  • Banded mongoose females regularly mate with their fathers and brothers.
  • Bed bugs: North Carolina State University found that bedbugs, in contrast to most other insects, tolerate incest and are able to genetically withstand the effects of inbreeding quite well.
  • Common fruit fly females prefer to mate with their own brothers over unrelated males.
  • Cottony cushion scales: 'It turns out that females in these hermaphrodite insects are not really fertilizing their eggs themselves, but instead are having this done by a parasitic tissue that infects them at birth,' says Laura Ross of Oxford University's Department of Zoology. ‘It seems that this infectious tissue derives from left-over sperm from their father, who has found a sneaky way of having more children by mating with his daughters.'
  • Adactylidium: The single male offspring mite mates with all the daughters when they are still in the mother. The females, now impregnated, cut holes in their mother's body so that they can emerge to find new thrips eggs. The male emerges as well, but does not look for food or new mates, and dies after a few hours. The females die at the age of 4 days, when their own offspring eat them alive from the inside.
White tiger in Gunma Safari Park

Domestic animals

Hereditary polycystic kidney disease is prevalent in the Persian cat breed, affecting almost half the population in some countries.
An intensive form of inbreeding where an individual S is mated to his daughter D1, granddaughter D2 and so on, in order to maximise the percentage of S's genes in the offspring. 87.5% of D3's genes would come from S, while D4 would receive 93.75% of their genes from S.

Breeding in domestic animals is primarily assortative breeding (see selective breeding). Without the sorting of individuals by trait, a breed could not be established, nor could poor genetic material be removed. Homozygosity is the case where similar or identical alleles combine to express a trait that is not otherwise expressed (recessiveness). Inbreeding exposes recessive alleles through increasing homozygosity.

Breeders must avoid breeding from individuals that demonstrate either homozygosity or heterozygosity for disease causing alleles. The goal of preventing the transfer of deleterious alleles may be achieved by reproductive isolation, sterilization, or, in the extreme case, culling. Culling is not strictly necessary if genetics are the only issue in hand. Small animals such as cats and dogs may be sterilized, but in the case of large agricultural animals, such as cattle, culling is usually the only economic option.

The issue of casual breeders who inbreed irresponsibly is discussed in the following quotation on cattle:

Meanwhile, milk production per cow per lactation increased from 17,444 lbs to 25,013 lbs from 1978 to 1998 for the Holstein breed. Mean breeding values for milk of Holstein cows increased by 4,829 lbs during this period. High producing cows are increasingly difficult to breed and are subject to higher health costs than cows of lower genetic merit for production (Cassell, 2001).

Intensive selection for higher yield has increased relationships among animals within breed and increased the rate of casual inbreeding.

Many of the traits that affect profitability in crosses of modern dairy breeds have not been studied in designed experiments. Indeed, all crossbreeding research involving North American breeds and strains is very dated (McAllister, 2001) if it exists at all.

The BBC produced two documentaries on dog inbreeding titled Pedigree Dogs Exposed and Pedigree Dogs Exposed: Three Years On that document the negative health consequences of excessive inbreeding.

Linebreeding

Linebreeding is a form of inbreeding. There is no clear distinction between the two terms, but linebreeding may encompass crosses between individuals and their descendants or two cousins. This method can be used to increase a particular animal's contribution to the population. While linebreeding is less likely to cause problems in the first generation than does inbreeding, over time, linebreeding can reduce the genetic diversity of a population and cause problems related to a too-small gene pool that may include an increased prevalence of genetic disorders and inbreeding depression.

Outcrossing

Outcrossing is where two unrelated individuals are crossed to produce progeny. In outcrossing, unless there is verifiable genetic information, one may find that all individuals are distantly related to an ancient progenitor. If the trait carries throughout a population, all individuals can have this trait. This is called the founder effect. In the well established breeds, that are commonly bred, a large gene pool is present. For example, in 2004, over 18,000 Persian cats were registered. A possibility exists for a complete outcross, if no barriers exist between the individuals to breed. However, it is not always the case, and a form of distant linebreeding occurs. Again it is up to the assortative breeder to know what sort of traits, both positive and negative, exist within the diversity of one breeding. This diversity of genetic expression, within even close relatives, increases the variability and diversity of viable stock.

Laboratory animals

Systematic inbreeding and maintenance of inbred strains of laboratory mice and rats is of great importance for biomedical research. The inbreeding guarantees a consistent and uniform animal model for experimental purposes and enables genetic studies in congenic and knock-out animals. In order to achieve a mouse strain that is considered inbred, a minimum of 20 sequential generations of sibling matings must occur. With each successive generation of breeding, homozygosity in the entire genome increases, eliminating heterozygous loci. With 20 generations of sibling matings, homozygosity is occurring at roughly 98.7% of all loci in the genome, allowing for these offspring to serve as animal models for genetic studies. The use of inbred strains is also important for genetic studies in animal models, for example to distinguish genetic from environmental effects. The mice that are inbred typically show considerably lower survival rates.

Humans

Global prevalence of consanguinity

Effects

Inbreeding increases homozygosity, which can increase the chances of the expression of deleterious or beneficial recessive alleles and therefore has the potential to either decrease or increase the fitness of the offspring. With continuous inbreeding, genetic variation is lost and homozygosity is increased, enabling the expression of recessive deleterious alleles in homozygotes. The coefficient of inbreeding, or the degree of inbreeding in an individual, is an estimate of the percent of homozygous alleles in the overall genome. The more biologically related the parents are, the greater the coefficient of inbreeding, since their genomes have many similarities already. This overall homozygosity becomes an issue when there are deleterious recessive alleles in the gene pool of the family. By pairing chromosomes of similar genomes, the chance for these recessive alleles to pair and become homozygous greatly increases, leading to offspring with autosomal recessive disorders. However, these deleterious effects are common for very close relatives but not for those related on the 3rd cousin or greater level, who exhibit increased fitness.

Inbreeding is especially problematic in small populations where the genetic variation is already limited. By inbreeding, individuals are further decreasing genetic variation by increasing homozygosity in the genomes of their offspring. Thus, the likelihood of deleterious recessive alleles to pair is significantly higher in a small inbreeding population than in a larger inbreeding population.

The fitness consequences of consanguineous mating have been studied since their scientific recognition by Charles Darwin in 1839. Some of the most harmful effects known from such breeding includes its effects on the mortality rate as well as on the general health of the offspring. Since the 1960s, there have been many studies to support such debilitating effects on the human organism. Specifically, inbreeding has been found to decrease fertility as a direct result of increasing homozygosity of deleterious recessive alleles. Fetuses produced by inbreeding also face a greater risk of spontaneous abortions due to inherent complications in development. Among mothers who experience stillbirths and early infant deaths, those that are inbreeding have a significantly higher chance of reaching repeated results with future offspring. Additionally, consanguineous parents possess a high risk of premature birth and producing underweight and undersized infants. Viable inbred offspring are also likely to be inflicted with physical deformities and genetically inherited diseases. Studies have confirmed an increase in several genetic disorders due to inbreeding such as blindness, hearing loss, neonatal diabetes, limb malformations, disorders of sex development, schizophrenia and several others. Moreover, there is an increased risk for congenital heart disease depending on the inbreeding coefficient (See coefficient of inbreeding) of the offspring, with significant risk accompanied by an F =.125 or higher.

Prevalence

The general negative outlook and eschewal of inbreeding that is prevalent in the Western world today has roots from over 2000 years ago. Specifically, written documents such as the Bible illustrate that there have been laws and social customs that have called for the abstention from inbreeding. Along with cultural taboos, parental education and awareness of inbreeding consequences have played large roles in minimizing inbreeding frequencies in areas like Europe. That being so, there are less urbanized and less populated regions across the world that have shown continuity in the practice of inbreeding.

The continuity of inbreeding is often either by choice or unavoidably due to the limitations of the geographical area. When by choice, the rate of consanguinity is highly dependent on religion and culture. In the Western world some Anabaptist groups are highly inbred because they originate from small founder populations and until today marriage outside the groups is not allowed for members. Especially the Reidenbach Old Order Mennonites and the Hutterites stem from very small founder populations. The same is true for some Hasidic and Haredi Jewish groups.

Of the practicing regions, Middle Eastern and northern Africa territories show the greatest frequencies of consanguinity. 

Among these populations with high levels of inbreeding, researchers have found several disorders prevalent among inbred offspring. In Lebanon, Saudi Arabia, Egypt, and in Israel, the offspring of consanguineous relationships have an increased risk of congenital malformations, congenital heart defects, congenital hydrocephalus and neural tube defects. Furthermore, among inbred children in Palestine and Lebanon, there is a positive association between consanguinity and reported cleft lip/palate cases. Historically, populations of Qatar have engaged in consanguineous relationships of all kinds, leading to high risk of inheriting genetic diseases. As of 2014, around 5% of the Qatari population suffered from hereditary hearing loss; most were descendants of a consanguineous relationship.

Royalty and nobility

Inter-nobility marriage was used as a method of forming political alliances among elites. These ties were often sealed only upon the birth of progeny within the arranged marriage. Thus marriage was seen as a union of lines of nobility and not as a contract between individuals.

Royal intermarriage was often practiced among European royal families, usually for interests of state. Over time, due to the relatively limited number of potential consorts, the gene pool of many ruling families grew progressively smaller, until all European royalty was related. This also resulted in many being descended from a certain person through many lines of descent, such as the numerous European royalty and nobility descended from the British Queen Victoria or King Christian IX of Denmark. The House of Habsburg was known for its intermarriages; the Habsburg lip often cited as an ill-effect. The closely related houses of Habsburg, Bourbon, Braganza and Wittelsbach also frequently engaged in first-cousin unions as well as the occasional double-cousin and uncle–niece marriages.

In ancient Egypt, royal women were believed to carry the bloodlines and so it was advantageous for a pharaoh to marry his sister or half-sister; in such cases a special combination between endogamy and polygamy is found. Normally, the old ruler's eldest son and daughter (who could be either siblings or half-siblings) became the new rulers. All rulers of the Ptolemaic dynasty uninterruptedly from Ptolemy IV (Ptolemy II married his sister but had no issue) were married to their brothers and sisters, so as to keep the Ptolemaic blood "pure" and to strengthen the line of succession. King Tutankhamun's mother is reported to have been the half-sister to his father, Cleopatra VII (also called Cleopatra VI) and Ptolemy XIII, who married and became co-rulers of ancient Egypt following their father's death, are the most widely known example.

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