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Thursday, September 2, 2021

Genetically modified bacteria

From Wikipedia, the free encyclopedia

Genetically modified bacteria were the first organisms to be modified in the laboratory, due to their simple genetics. These organisms are now used for several purposes, and are particularly important in producing large amounts of pure human proteins for use in medicine.

History

The first example of this occurred in 1978 when Herbert Boyer, working at a University of California laboratory, took a version of the human insulin gene and inserted into the bacterium Escherichia coli to produce synthetic "human" insulin. Four years later, it was approved by the U.S. Food and Drug Administration.

Research

Left: Bacteria transformed with pGLO under ambient light Right: Bacteria transformed with pGLO visualised under ultraviolet light

Bacteria were the first organisms to be genetically modified in the laboratory, due to the relative ease of modifying their chromosomes. This ease made them important tools for the creation of other GMOs. Genes and other genetic information from a wide range of organisms can be added to a plasmid and inserted into bacteria for storage and modification. Bacteria are cheap, easy to grow, clonal, multiply quickly, are relatively easy to transform, and can be stored at -80 °C almost indefinitely. Once a gene is isolated it can be stored inside the bacteria, providing an unlimited supply for research. The large number of custom plasmids make manipulating DNA excised from bacteria relatively easy.

Their ease of use has made them great tools for scientists looking to study gene function and evolution. Most DNA manipulation takes place within bacterial plasmids before being transferred to another host. Bacteria are the simplest model organism and most of our early understanding of molecular biology comes from studying Escherichia coli. Scientists can easily manipulate and combine genes within the bacteria to create novel or disrupted proteins and observe the effect this has on various molecular systems. Researchers have combined the genes from bacteria and archaea, leading to insights on how these two diverged in the past. In the field of synthetic biology, they have been used to test various synthetic approaches, from synthesizing genomes to creating novel nucleotides.

Food

Bacteria have been used in the production of food for a very long time, and specific strains have been developed and selected for that work on an industrial scale. They can be used to produce enzymes, amino acids, flavourings, and other compounds used in food production. With the advent of genetic engineering, new genetic changes can easily be introduced into these bacteria. Most food-producing bacteria are lactic acid bacteria, and this is where the majority of research into genetically engineering food-producing bacteria has gone. The bacteria can be modified to operate more efficiently, reduce toxic byproduct production, increase output, create improved compounds, and remove unnecessary pathways. Food products from genetically modified bacteria include alpha-amylase, which converts starch to simple sugars, chymosin, which clots milk protein for cheese making, and pectinesterase, which improves fruit juice clarity.

In cheese

Chymosin is an enzyme found in a calf's stomach. This helps the calf break down the milk to digest. Chymosin is necessary in order to make cheese. It turns the milk into cheese. Scientists have found a way to alter yeast to grow Chymosin enzymes for making cheese. This process is much more efficient because previously calves had to be slaughtered in order to extract the Chymosin from the inner lining of the stomach. Also this offers a vegetarian friendly way to make cheese. It depends on what and how the Bacteria does the process.

Industrial

Genetically modified bacteria are used to produce large amounts of proteins for industrial use. Generally the bacteria are grown to a large volume before the gene encoding the protein is activated. The bacteria are then harvested and the desired protein purified from them. The high cost of extraction and purification has meant that only high value products have been produced at an industrial scale.

Pharmaceutical production

The majority of the industrial products from bacteria are human proteins for use in medicine. Many of these proteins are impossible or difficult to obtain via natural methods and they are less likely to be contaminated with pathogens, making them safer. Prior to recombinant protein products, several treatments were derived from cadavers or other donated body fluids and could transmit diseases. Indeed, transfusion of blood products had previously led to unintentional infection of haemophiliacs with HIV or hepatitis C; similarly, treatment with human growth hormone derived from cadaver pituitary glands may have led to outbreaks of Creutzfeldt–Jakob disease.

The first medicinal use of GM bacteria was to produce the protein insulin to treat diabetes. Other medicines produced include clotting factors to treat haemophilia, human growth hormone to treat various forms of dwarfism, interferon to treat some cancers, erythropoietin for anemic patients, and tissue plasminogen activator which dissolves blood clots. Outside of medicine they have been used to produce biofuels. There is interest in developing an extracellular expression system within the bacteria to reduce costs and make the production of more products economical.

Health

With greater understanding of the role that the micobiome plays in human health, there is the potential to treat diseases by genetically altering the bacteria to, themselves, be therapeutic agents. Ideas include altering gut bacteria so they destroy harmful bacteria, or using bacteria to replace or increase deficient enzymes or proteins. One research focus is to modify Lactobacillus, bacteria that naturally provide some protection against HIV, with genes that will further enhance this protection. The bacteria which generally cause tooth decay have been engineered to no longer produce tooth-corroding lactic acid. These transgenic bacteria, if allowed to colonize a person's mouth, could perhaps reduce the formation of cavities. Transgenic microbes have also been used in recent research to kill or hinder tumors, and to fight Crohn's disease.

If the bacteria do not form colonies inside the patient, the person must repeatedly ingest the modified bacteria in order to get the required doses. Enabling the bacteria to form a colony could provide a more long-term solution, but could also raise safety concerns as interactions between bacteria and the human body are less well understood than with traditional drugs.

One example of such an intermediate, which only forms short-term colonies in the gastrointestinal tract, may be Lactobacillus Acidophilus MPH734. This is used as a specific in the treatment of Lactose Intolerance. This genetically modified version of Lactobacillus acidophilus bacteria produces a missing enzyme called lactase which is used for the digestion of lactose found in dairy products or, more commonly, in food prepared with dairy products. The short term colony is induced over a one-week, 21-pill treatment regimen, after which, the temporary colony can produce lactase for three months or more before it is removed from the body by a natural processes. The induction regimen can be repeated as often as necessary to maintain protection from the symptoms of lactose intolerance, or discontinued with no consequences, except the return of the original symptoms.

There are concerns that horizontal gene transfer to other bacteria could have unknown effects. As of 2018 there are clinical trials underway testing the efficacy and safety of these treatments.

Agriculture

For over a century bacteria have been used in agriculture. Crops have been inoculated with Rhizobia (and more recently Azospirillum) to increase their production or to allow them to be grown outside their original habitat. Application of Bacillus thuringiensis (Bt) and other bacteria can help protect crops from insect infestation and plant diseases. With advances in genetic engineering, these bacteria have been manipulated for increased efficiency and expanded host range. Markers have also been added to aid in tracing the spread of the bacteria. The bacteria that naturally colonise certain crops have also been modified, in some cases to express the Bt genes responsible for pest resistance. Pseudomonas strains of bacteria cause frost damage by nucleating water into ice crystals around themselves. This led to the development of ice-minus bacteria, that have the ice-forming genes removed. When applied to crops they can compete with the ice-plus bacteria and confer some frost resistance.

This artwork is made with bacteria modified to express 8 different colours of fluorescent proteins.

Other uses

Other uses for genetically modified bacteria include bioremediation, where the bacteria are used to convert pollutants into a less toxic form. Genetic engineering can increase the levels of the enzymes used to degrade a toxin or to make the bacteria more stable under environmental conditions. GM bacteria have also been developed to leach copper from ore, clean up mercury pollution and detect arsenic in drinking water. Bioart has also been created using genetically modified bacteria. In the 1980s artist Joe Davis and geneticist Dana Boyd converted the Germanic symbol for femininity (ᛉ) into binary code and then into a DNA sequence, which was then expressed in Escherichia coli. This was taken a step further in 2012, when a whole book was encoded onto DNA. Paintings have also been produced using bacteria transformed with fluorescent proteins.

Bacteria-synthesized transgenic products

Vulgar Latin

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

Vulgar Latin, also known as Popular or Colloquial Latin, is non-literary Latin spoken from the Late Roman Republic onwards. Depending on the time period, its literary counterpart was either Classical Latin or Late Latin.

Origin of the term

During the Classical period, Roman authors referred to the informal, everyday variety of their own language as sermo plebeius or sermo vulgaris, meaning "common speech".

The modern usage of the term Vulgar Latin dates to the Renaissance, when Italian thinkers began to theorize that their own language originated in a sort of "corrupted" Latin that they assumed formed an entity distinct from the literary Classical variety, though opinions differed greatly on the nature of this "vulgar" dialect.

The early 19th-century French linguist Raynouard is often regarded as the father of modern Romance philology. Observing that the Romance languages have many features in common that are not found in Latin, at least not in "proper" or Classical Latin, he concluded that the former must have all had some common ancestor (which he believed most closely resembled Old Occitan) that replaced Latin some time before the year 1000. This he dubbed la langue romane or "the Roman language".

The first truly modern treatise on Romance linguistics, however, and the first to apply the comparative method, was Friedrich Christian Diez's seminal Grammar of the Romance Languages.

Sources

Evidence for the features of non-literary Latin comes from the following sources:

  • Recurrent grammatical, syntactic, or orthographic mistakes in Latin epigraphy.
  • The insertion, whether intentional or not, of colloquial terms or constructions into contemporary texts.
  • Explicit mention of certain constructions or pronunciation habits by Roman grammarians.
  • The pronunciation of Roman-era lexical borrowings into neighboring languages such as Basque, Albanian, or Welsh.

History

By the end of the first century AD the Romans had conquered the entire Mediterranean Basin and established hundreds of colonies in the conquered provinces. Over time this—along with other factors that encouraged linguistic and cultural assimilation, such as political unity, frequent travel and commerce, military service, etc.—made Latin the predominant language throughout the western Mediterranean. Latin itself was subject to the same assimilatory tendencies, such that its varieties had probably become more uniform by the time the Western Empire fell in 476 than they had been before it. That is not to say that the language had been static for all those years, but rather that ongoing changes tended to spread to all regions.

All of these homogenizing factors were disrupted or voided by a long string of calamities. Although Justinian succeeded in reconquering Italy, Africa, and the southern part of Iberia in the period 533–554, the Empire was hit by one of the deadliest plagues in recorded history in 541, one that would recur six more times before 610. Under his successors most of the Italian peninsula was lost to the Lombards by c. 572, most of southern Iberia to the Visigoths by c. 615, and most of the Balkans to the Slavs and Avars by c. 620. All this was possible due to Roman preoccupation with wars against Persia, the last of which lasted nearly three decades and exhausted both empires. Taking advantage of this, the Arabs invaded and occupied Syria and Egypt by 642, greatly weakening the Empire and ending its centuries of domination over the Mediterranean. They went on to take the rest of North Africa by c. 699 and soon invaded the Visigothic Kingdom as well, seizing most of Iberia from it by c. 716.

It is from approximately the seventh century onward that regional differences proliferate in the language of Latin documents, indicating the fragmentation of Latin into the incipient Romance languages. Until then Latin appears to have been remarkably homogenous, as far as can be judged from its written records, although careful statistical analysis reveals regional differences in the treatment of the Latin vowel /ĭ/ and in the progression of betacism by about the fifth century.

Vocabulary

Lexical turnover

Over the centuries, spoken Latin lost various lexical items and replaced them with native coinages; with borrowings from neighbouring languages such as Gaulish, Germanic, or Greek; or with other native words that had undergone semantic shift. The literary language generally retained the older words, however.

A textbook example is the general replacement of the suppletive Classical verb ferre, meaning 'carry', with the regular portare. Similarly, the Classical loqui, meaning 'speak', was replaced by a variety of alternatives such as the native fabulari and narrare or the Greek borrowing parabolare.

Classical Latin particles fared especially poorly, with all of the following vanishing from popular speech: an, at, autem, donec, enim, etiam, haud, igitur, ita, nam, postquam, quidem, quin, quoad, quoque, sed, sive, utrum, and vel.

Semantic drift

Many surviving words experienced a shift in meaning. Some notable cases are civitas ('citizenry' 'city', replacing urbs); focus ('hearth' 'fire', replacing ignis); manducare ('chew' 'eat', replacing edere); causa ('subject matter' 'thing', competing with res); mittere ('send' → 'put', competing with ponere); necare ('murder' 'drown', competing with submergere); pacare ('placate' 'pay', competing with solvere), and totus ('whole' 'all, every', competing with omnis).

Phonological development

Consonantism

Loss of nasals

  • Word-final /m/ was lost in polysyllabic words. In monosyllables it tended to survive as /n/.
  • /n/ was usually lost before fricatives, resulting in compensatory lengthening of the preceding vowel (e.g. sponsa ‘fiancée’ > spōsa).

Palatalization

Front vowels in hiatus (after a consonant and before another vowel) became [j], which palatalized preceding consonants.

Fricativization

/w/ (except after /k/) and intervocalic /b/ merge as the bilabial fricative /β/.

Simplification of consonant clusters

  • The cluster /nkt/ reduced to [ŋt].
  • /kw/ delabialized to /k/ before back vowels.
  • /ks/ before or after a consonant, or at the end of a word, reduced to /s/.

Vocalism

Monophthongization

  • /ae̯/ and /oe̯/ monophthongized to [ɛː] and [eː] respectively by around the second century AD.

Loss of vowel quantity

The system of phonemic vowel length collapsed by the fifth century AD, leaving quality differences as the distinguishing factor between vowels; the paradigm thus changed from /ī ĭ ē ĕ ā ă ŏ ō ŭ ū/ to /i ɪ e ɛ a ɔ o ʊ u/. Concurrently, stressed vowels in open syllables lengthened.

Loss of near-close front vowel

Towards the end of the Roman Empire /ɪ/ merged with /e/ in most regions, although not in Africa or a few peripheral areas in Italy.

Grammar

Romance articles

It is difficult to place the point in which the definite article, absent in Latin but present in all Romance languages, arose, largely because the highly colloquial speech in which it arose was seldom written down until the daughter languages had strongly diverged; most surviving texts in early Romance show the articles fully developed.

Definite articles evolved from demonstrative pronouns or adjectives (an analogous development is found in many Indo-European languages, including Greek, Celtic and Germanic); compare the fate of the Latin demonstrative adjective ille, illa, illud "that", in the Romance languages, becoming French le and la (Old French li, lo, la), Catalan and Spanish el, la and lo, Occitan lo and la, Portuguese o and a (elision of -l- is a common feature of Portuguese) and Italian il, lo and la. Sardinian went its own way here also, forming its article from ipse, ipsa "this" (su, sa); some Catalan and Occitan dialects have articles from the same source. While most of the Romance languages put the article before the noun, Romanian has its own way, by putting the article after the noun, e.g. lupul ("the wolf" – from *lupum illum) and omul ("the man" – *homo illum), possibly a result of being within the Balkan sprachbund.

This demonstrative is used in a number of contexts in some early texts in ways that suggest that the Latin demonstrative was losing its force. The Vetus Latina Bible contains a passage Est tamen ille daemon sodalis peccati ("The devil is a companion of sin"), in a context that suggests that the word meant little more than an article. The need to translate sacred texts that were originally in Koine Greek, which had a definite article, may have given Christian Latin an incentive to choose a substitute. Aetheria uses ipse similarly: per mediam vallem ipsam ("through the middle of the valley"), suggesting that it too was weakening in force.

Another indication of the weakening of the demonstratives can be inferred from the fact that at this time, legal and similar texts begin to swarm with praedictus, supradictus, and so forth (all meaning, essentially, "aforesaid"), which seem to mean little more than "this" or "that". Gregory of Tours writes, Erat autem... beatissimus Anianus in supradicta civitate episcopus ("Blessed Anianus was bishop in that city.") The original Latin demonstrative adjectives were no longer felt to be strong or specific enough.

In less formal speech, reconstructed forms suggest that the inherited Latin demonstratives were made more forceful by being compounded with ecce (originally an interjection: "behold!"), which also spawned Italian ecco through eccum, a contracted form of ecce eum. This is the origin of Old French cil (*ecce ille), cist (*ecce iste) and ici (*ecce hic); Italian questo (*eccum istum), quello (*eccum illum) and (now mainly Tuscan) codesto (*eccum tibi istum), as well as qui (*eccu hic), qua (*eccum hac); Spanish and Occitan aquel and Portuguese aquele (*eccum ille); Spanish acá and Portuguese (*eccum hac); Spanish aquí and Portuguese aqui (*eccum hic); Portuguese acolá (*eccum illac) and aquém (*eccum inde); Romanian acest (*ecce iste) and acela (*ecce ille), and many other forms.

On the other hand, even in the Oaths of Strasbourg, no demonstrative appears even in places where one would clearly be called for in all the later languages (pro christian poblo – "for the Christian people"). Using the demonstratives as articles may have still been considered overly informal for a royal oath in the 9th century. Considerable variation exists in all of the Romance vernaculars as to their actual use: in Romanian, the articles are suffixed to the noun (or an adjective preceding it), as in other languages of the Balkan sprachbund and the North Germanic languages.

The numeral unus, una (one) supplies the indefinite article in all cases (again, this is a common semantic development across Europe). This is anticipated in Classical Latin; Cicero writes cum uno gladiatore nequissimo ("with a most immoral gladiator"). This suggests that unus was beginning to supplant quidam in the meaning of "a certain" or "some" by the 1st century BC.

Loss of neuter gender

1st and 2nd adjectival declension paradigm in Classical Latin:
e.g. altus ("tall")
Excludes vocative.

singular plural
masculine neuter feminine masculine neuter feminine
nominative altus altum alta altī alta altae
accusative altum altam altōs alta altās
dative altō altae altīs
ablative altō altā altīs
genitive altī altae altōrum altārum

The three grammatical genders of Classical Latin were replaced by a two-gender system in most Romance languages.

The neuter gender of classical Latin was in most cases identical with the masculine both syntactically and morphologically. The confusion had already started in Pompeian graffiti, e.g. cadaver mortuus for cadaver mortuum ("dead body"), and hoc locum for hunc locum ("this place"). The morphological confusion shows primarily in the adoption of the nominative ending -us ( after -r) in the o-declension.

In Petronius's work, one can find balneus for balneum ("bath"), fatus for fatum ("fate"), caelus for caelum ("heaven"), amphitheater for amphitheatrum ("amphitheatre"), vinus for vinum ("wine"), and conversely, thesaurum for thesaurus ("treasure"). Most of these forms occur in the speech of one man: Trimalchion, an uneducated Greek (i.e. foreign) freedman.

In modern Romance languages, the nominative s-ending has been largely abandoned, and all substantives of the o-declension have an ending derived from -um: -u, -o, or . E.g., masculine murum ("wall"), and neuter caelum ("sky") have evolved to: Italian muro, cielo; Portuguese muro, céu; Spanish muro, cielo, Catalan mur, cel; Romanian mur, cieru>cer; French mur, ciel. However, Old French still had -s in the nominative and in the accusative in both words: murs, ciels [nominative] – mur, ciel [oblique]. 

For some neuter nouns of the third declension, the oblique stem was productive; for others, the nominative/accusative form, (the two were identical in Classical Latin). Evidence suggests that the neuter gender was under pressure well back into the imperial period. French (le) lait, Catalan (la) llet, Occitan (lo) lach, Spanish (la) leche, Portuguese (o) leite, Italian language (il) latte, Leonese (el) lleche and Romanian lapte(le) ("milk"), all derive from the non-standard but attested Latin nominative/accusative neuter lacte or accusative masculine lactem. In Spanish the word became feminine, while in French, Portuguese and Italian it became masculine (in Romanian it remained neuter, lapte/lăpturi). Other neuter forms, however, were preserved in Romance; Catalan and French nom, Leonese, Portuguese and Italian nome, Romanian nume ("name") all preserve the Latin nominative/accusative nomen, rather than the oblique stem form *nominem (which nevertheless produced Spanish nombre).

Typical Italian endings

Nouns Adjectives and determiners

singular plural singular plural
masculine giardino giardini buono buoni
feminine donna donne buona buone
neuter uovouovabuonobuone

Most neuter nouns had plural forms ending in -A or -IA; some of these were reanalysed as feminine singulars, such as gaudium ("joy"), plural gaudia; the plural form lies at the root of the French feminine singular (la) joie, as well as of Catalan and Occitan (la) joia (Italian la gioia is a borrowing from French); the same for lignum ("wood stick"), plural ligna, that originated the Catalan feminine singular noun (la) llenya, and Spanish (la) leña. Some Romance languages still have a special form derived from the ancient neuter plural which is treated grammatically as feminine: e.g., BRACCHIUM : BRACCHIA "arm(s)" → Italian (il) braccio : (le) braccia, Romanian braț(ul) : brațe(le). Cf. also Merovingian Latin ipsa animalia aliquas mortas fuerant.

Alternations in Italian heteroclitic nouns such as l'uovo fresco ("the fresh egg") / le uova fresche ("the fresh eggs") are usually analysed as masculine in the singular and feminine in the plural, with an irregular plural in -a. However, it is also consistent with their historical development to say that uovo is simply a regular neuter noun (ovum, plural ova) and that the characteristic ending for words agreeing with these nouns is -o in the singular and -e in the plural. The same alternation in gender exists in certain Romanian nouns, but is considered regular as it is more common than in Italian. Thus, a relict neuter gender can arguably be said to persist in Italian and Romanian.

In Portuguese, traces of the neuter plural can be found in collective formations and words meant to inform a bigger size or sturdiness. Thus, one can use ovo/ovos ("egg/eggs") and ova/ovas ("roe", "a collection of eggs"), bordo/bordos ("section(s) of an edge") and borda/bordas ("edge/edges"), saco/sacos ("bag/bags") and saca/sacas ("sack/sacks"), manto/mantos ("cloak/cloaks") and manta/mantas ("blanket/blankets"). Other times, it resulted in words whose gender may be changed more or less arbitrarily, like fruto/fruta ("fruit"), caldo/calda (broth"), etc.

These formations were especially common when they could be used to avoid irregular forms. In Latin, the names of trees were usually feminine, but many were declined in the second declension paradigm, which was dominated by masculine or neuter nouns. Latin pirus ("pear tree"), a feminine noun with a masculine-looking ending, became masculine in Italian (il) pero and Romanian păr(ul); in French and Spanish it was replaced by the masculine derivations (le) poirier, (el) peral; and in Portuguese and Catalan by the feminine derivations (a) pereira, (la) perera.

As usual, irregularities persisted longest in frequently used forms. From the fourth declension noun manus ("hand"), another feminine noun with the ending -us, Italian and Spanish derived (la) mano, Romanian mânu>mâna pl (reg.)mâini/mâini, Catalan (la) , and Portuguese (a) mão, which preserve the feminine gender along with the masculine appearance.

Except for the Italian and Romanian heteroclitic nouns, other major Romance languages have no trace of neuter nouns, but still have neuter pronouns. French celui-ci / celle-ci / ceci ("this"), Spanish éste / ésta / esto ("this"), Italian: gli / le / ci ("to him" /"to her" / "to it"), Catalan: ho, açò, això, allò ("it" / this / this-that / that over there); Portuguese: todo / toda / tudo ("all of him" / "all of her" / "all of it").

In Spanish, a three-way contrast is also made with the definite articles el, la, and lo. The last is used with nouns denoting abstract categories: lo bueno, literally "that which is good", from bueno: good.

  1. In a few isolated masculine nouns, the s has been either preserved or reinstated in the modern languages, for example FILIUS ("son") > French fils, DEUS ("god") > Spanish dios and Portuguese deus, and particularly in proper names: Spanish Carlos, Marcos, in the conservative orthography of French Jacques, Charles, Jules, etc.

Loss of oblique cases

The Vulgar Latin vowel shifts caused the merger of several case endings in the nominal and adjectival declensions. Some of the causes include: the loss of final m, the merger of ă with ā, and the merger of ŭ with ō (see tables). Thus, by the 5th century, the number of case contrasts had been drastically reduced.

Evolution of a 1st declension noun:
caepa/cēpa ("onion") (feminine singular)

Classical
(c. 1st century)
Vulgar
(c. 5th cent.)
Modern
Romanian
nominative caepa, cēpa *cépa ceapă
accusative caepam, cēpam
ablative caepā, cēpā
dative caepae, cēpae *cépe cepe
genitive
Evolution of a 2nd declension noun:
mūrus ("wall") (masculine singular)

Classical
(c. 1st cent.)
Vulgar
(c. 5th cent.)
Old French
(c. 11th cent.)
nominative mūrus *múros murs
accusative mūrum *múru mur
ablative mūrō *múro
dative
genitive mūrī *múri

There also seems to be a marked tendency to confuse different forms even when they had not become homophonous (like the generally more distinct plurals), which indicates that nominal declension was shaped not only by phonetic mergers, but also by structural factors. As a result of the untenability of the noun case system after these phonetic changes, Vulgar Latin shifted from a markedly synthetic language to a more analytic one.

The genitive case died out around the 3rd century AD, according to Meyer-Lübke, and began to be replaced by "de" + noun (which originally meant "about/concerning", weakened to "of") as early as the 2nd century BC. Exceptions of remaining genitive forms are some pronouns, certain fossilized expressions and some proper names. For example, French jeudi ("Thursday") < Old French juesdi < Vulgar Latin "jovis diēs"; Spanish es menester ("it is necessary") < "est ministeri"; and Italian terremoto ("earthquake") < "terrae motu" as well as names like Paoli, Pieri.

The dative case lasted longer than the genitive, even though Plautus, in the 2nd century BC, already shows some instances of substitution by the construction "ad" + accusative. For example, "ad carnuficem dabo".

The accusative case developed as a prepositional case, displacing many instances of the ablative. Towards the end of the imperial period, the accusative came to be used more and more as a general oblique case.

Despite increasing case mergers, nominative and accusative forms seem to have remained distinct for much longer, since they are rarely confused in inscriptions. Even though Gaulish texts from the 7th century rarely confuse both forms, it is believed that both cases began to merge in Africa by the end of the empire, and a bit later in parts of Italy and Iberia. Nowadays, Romanian maintains a two-case system, while Old French and Old Occitan had a two-case subject-oblique system.

This Old French system was based largely on whether or not the Latin case ending contained an "s" or not, with the "s" being retained but all vowels in the ending being lost (as with veisin below). But since this meant that it was easy to confuse the singular nominative with the plural oblique, and the plural nominative with the singular oblique, this case system ultimately collapsed as well, and Middle French adopted one case (usually the oblique) for all purposes, leaving the Romanian the only one to survive to the present day.

Evolution of a masculine noun
in Old French: veisin ("neighbor").
(definite article in parentheses).

Classical Latin
(1st cent.)
Old French
(11th cent.)
singular nominative "vīcīnus" (li) veisins
accusative "vīcīnum" (le) veisin
genitive "vīcīnī"
dative "vīcīnō"
ablative
plural nominative "vīcīnī" (li) veisin
accusative "vīcīnōs" (les) veisins
genitive "vīcīnōrum"
dative "vīcīnīs"
ablative

Wider use of prepositions

Loss of a productive noun case system meant that the syntactic purposes it formerly served now had to be performed by prepositions and other paraphrases. These particles increased in number, and many new ones were formed by compounding old ones. The descendant Romance languages are full of grammatical particles such as Spanish donde, "where", from Latin de + unde, or French dès, "since", from de + ex, while the equivalent Spanish and Portuguese desde is de + ex + de. Spanish después and Portuguese depois, "after", represent de + ex + post.

Some of these new compounds appear in literary texts during the late empire; French dehors, Spanish de fuera and Portuguese de fora ("outside") all represent de + foris (Romanian afarăad + foris), and we find Jerome writing stulti, nonne qui fecit, quod de foris est, etiam id, quod de intus est fecit? (Luke 11.40: "ye fools, did not he, that made which is without, make that which is within also?"). In some cases, compounds were created by combining a large number of particles, such as the Romanian adineauri ("just recently") from ad + de + in + illa + hora.

Classical Latin:

Marcus patrī librum dat. "Marcus is giving [his] father [a/the] book."

Vulgar Latin:

*Marcos da libru a patre. "Marcus is giving [a/the] book to [his] father."

Just as in the disappearing dative case, colloquial Latin sometimes replaced the disappearing genitive case with the preposition de followed by the ablative, then eventually the accusative (oblique).

Classical Latin:

Marcus mihi librum patris dat. "Marcus is giving me [his] father's book.

Vulgar Latin:

*Marcos mi da libru de patre. "Marcus is giving me [the] book of [his] father."

Pronouns

Unlike in the nominal and adjectival inflections, pronouns kept great part of the case distinctions. However, many changes happened. For example, the /ɡ/ of ego was lost by the end of the empire, and eo appears in manuscripts from the 6th century.

Reconstructed pronominal system of Vulgar Latin

1st person 2nd person 3rd person

singular plural singular plural
Nominative *éo *nọs *tu *vọs
Dative *mi *nọ́be(s) *ti, *tẹ́be *vọ́be(s) *si, *sẹ́be
Accusative *mẹ *nọs *tẹ *vọs *sẹ

Adverbs

Classical Latin had a number of different suffixes that made adverbs from adjectives: cārus, "dear", formed cārē, "dearly"; ācriter, "fiercely", from ācer; crēbrō, "often", from crēber. All of these derivational suffixes were lost in Vulgar Latin, where adverbs were invariably formed by a feminine ablative form modifying mente, which was originally the ablative of mēns, and so meant "with a ... mind". So vēlōx ("quick") instead of vēlōciter ("quickly") gave veloci mente (originally "with a quick mind", "quick-mindedly") This explains the widespread rule for forming adverbs in many Romance languages: add the suffix -ment(e) to the feminine form of the adjective. The development illustrates a textbook case of grammaticalization in which an autonomous form, the noun meaning 'mind', while still in free lexical use in e.g. Italian venire in mente 'come to mind', becomes a productive suffix for forming adverbs in Romance such as Italian chiaramente, Spanish claramente 'clearly', with both its source and its meaning opaque in that usage other than as adverb formant.

Verbs

The Cantar de Mio Cid (Song of my Cid) is the earliest Spanish text

In general, the verbal system in the Romance languages changed less from Classical Latin than did the nominal system.

The four conjugational classes generally survived. The second and third conjugations already had identical imperfect tense forms in Latin, and also shared a common present participle. Because of the merging of short i with long ē in most of Vulgar Latin, these two conjugations grew even closer together. Several of the most frequently-used forms became indistinguishable, while others became distinguished only by stress placement:


Infinitive 1st 2nd 3rd 1st 2nd 3rd Imperative
singular
singular plural
Second conjugation (Classical) -ēre -eō -ēs -et -ēmus -ētis -ent
Second conjugation (Vulgar) *-ẹ́re *-(j)o *-es *-e(t) *-ẹ́mos *-ẹ́tes *-en(t) *-e
Third conjugation (Vulgar) *-ere *-o *-emos *-etes *-on(t)
Third conjugation (Classical) -ere -is -it -imus -itis -unt -e

These two conjugations came to be conflated in many of the Romance languages, often by merging them into a single class while taking endings from each of the original two conjugations. Which endings survived was different for each language, although most tended to favour second conjugation endings over the third conjugation. Spanish, for example, mostly eliminated the third conjugation forms in favour of second conjugation forms.

French and Catalan did the same, but tended to generalise the third conjugation infinitive instead. Catalan in particular almost eliminated the second conjugation ending over time, reducing it to a small relic class. In Italian, the two infinitive endings remained separate (but spelled identically), while the conjugations merged in most other respects much as in the other languages. However, the third-conjugation third-person plural present ending survived in favour of the second conjugation version, and was even extended to the fourth conjugation. Romanian also maintained the distinction between the second and third conjugation endings.

In the perfect, many languages generalized the -aui ending most frequently found in the first conjugation. This led to an unusual development; phonetically, the ending was treated as the diphthong /au/ rather than containing a semivowel /awi/, and in other cases the /w/ sound was simply dropped. We know this because it did not participate in the sound shift from /w/ to /β̞/. Thus Latin amaui, amauit ("I loved; he/she loved") in many areas became proto-Romance *amai and *amaut, yielding for example Portuguese amei, amou. This suggests that in the spoken language, these changes in conjugation preceded the loss of /w/.

Another major systemic change was to the future tense, remodelled in Vulgar Latin with auxiliary verbs. A new future was originally formed with the auxiliary verb habere, *amare habeo, literally "to love I have" (cf. English "I have to love", which has shades of a future meaning). This was contracted into a new future suffix in Western Romance forms, which can be seen in the following modern examples of "I will love":

  • French: j'aimerai (je + aimer + ai) ← aimer ["to love"] + ai ["I have"].
  • Portuguese and Galician: amarei (amar + [h]ei) ← amar ["to love"] + hei ["I have"]
  • Spanish and Catalan: amaré (amar + [h]e) ← amar ["to love"] + he ["I have"].
  • Italian: amerò (amar + [h]o) ← amare ["to love"] + ho ["I have"].

A periphrastic construction of the form 'to have to' (late Latin habere ad) used as future is characteristic of Sardinian:

  • Ap'a istàre < apo a istàre 'I will stay'
  • Ap'a nàrrere < apo a nàrrer 'I will say'

An innovative conditional (distinct from the subjunctive) also developed in the same way (infinitive + conjugated form of habere). The fact that the future and conditional endings were originally independent words is still evident in literary Portuguese, which in these tenses allows clitic object pronouns to be incorporated between the root of the verb and its ending: "I will love" (eu) amarei, but "I will love you" amar-te-ei, from amar + te ["you"] + (eu) hei = amar + te + [h]ei = amar-te-ei.

In Spanish, Italian and Portuguese, personal pronouns can still be omitted from verb phrases as in Latin, as the endings are still distinct enough to convey that information: venio > Sp vengo ("I come"). In French, however, all the endings are typically homophonous except the first and second person (and occasionally also third person) plural, so the pronouns are always used (je viens) except in the imperative.

Contrary to the millennia-long continuity of much of the active verb system, which has now survived 6000 years of known evolution, the synthetic passive voice was utterly lost in Romance, being replaced with periphrastic verb forms—composed of the verb "to be" plus a passive participle—or impersonal reflexive forms—composed of a verb and a passivizing pronoun.

Apart from the grammatical and phonetic developments there were many cases of verbs merging as complex subtleties in Latin were reduced to simplified verbs in Romance. A classic example of this are the verbs expressing the concept "to go". Consider three particular verbs in Classical Latin expressing concepts of "going": ire, vadere, and *ambitare. In Spanish and Portuguese ire and vadere merged into the verb ir, which derives some conjugated forms from ire and some from vadere. andar was maintained as a separate verb derived from ambitare.

Italian instead merged vadere and ambitare into the verb andare. At the extreme French merged three Latin verbs with, for example, the present tense deriving from vadere and another verb ambulare (or something like it) and the future tense deriving from ire. Similarly the Romance distinction between the Romance verbs for "to be", essere and stare, was lost in French as these merged into the verb être. In Italian, the verb essere inherited both Romance meanings of "being essentially" and "being temporarily of the quality of", while stare specialized into a verb denoting location or dwelling, or state of health.

Copula

The copula (that is, the verb signifying "to be") of Classical Latin was esse. This evolved to *essere in Vulgar Latin by attaching the common infinitive suffix -re to the classical infinitive; this produced Italian essere and French être through Proto-Gallo-Romance *essre and Old French estre as well as Spanish and Portuguese ser (Romanian a fi derives from fieri, which means "to become").

In Vulgar Latin a second copula developed utilizing the verb stare, which originally meant (and is cognate with) "to stand", to denote a more temporary meaning. That is, *essere signified the essence, while stare signified the state. Stare evolved to Spanish and Portuguese estar and Old French ester (both through *estare), while Italian and Romanian retained the original form.

The semantic shift that underlies this evolution is more or less as follows: A speaker of Classical Latin might have said: vir est in foro, meaning "the man is in/at the marketplace". The same sentence in Vulgar Latin could have been *(h)omo stat in foro, "the man stands in/at the marketplace", replacing the est (from esse) with stat (from stare), because "standing" was what was perceived as what the man was actually doing.

The use of stare in this case was still semantically transparent assuming that it meant "to stand", but soon the shift from esse to stare became more widespread. In the Iberian peninsula esse ended up only denoting natural qualities that would not change, while stare was applied to transient qualities and location. In Italian, stare is used mainly for location, transitory state of health (sta male 's/he is ill' but è gracile 's/he is puny') and, as in Spanish, for the eminently transient quality implied in a verb's progressive form, such as sto scrivendo to express 'I am writing'.

The historical development of the stare + gerund progressive in those Romance languages that have it seems to have been a passage from a usage such as sto pensando 'I stand/stay (here) thinking', in which the stare form carries the full semantic load of 'stand, stay' to grammaticalization of the construction as expression of progressive aspect (Similar in concept to the English verbal construction of "I am still thinking"). The process of reanalysis that took place over time bleached the semantics of stare so that when used in combination with the gerund the form became solely a grammatical marker of subject and tense (e.g. sto = subject first person singular, present; stavo = subject first person singular, past), no longer a lexical verb with the semantics of 'stand' (not unlike the auxiliary in compound tenses that once meant 'have, possess', but is now semantically empty: j'ai écrit, ho scritto, he escrito, etc.). Whereas sto scappando would once have been semantically strange at best (?'I stay escaping'), once grammaticalization was achieved, collocation with a verb of inherent mobility was no longer contradictory, and sto scappando could and did become the normal way to express 'I am escaping'. (Although it might be objected that in sentences like Spanish la catedral está en la ciudad, "the cathedral is in the city" this is also unlikely to change, but all locations are expressed through estar in Spanish, as this usage originally conveyed the sense of "the cathedral stands in the city").

Word order typology

Classical Latin in most cases adopted an SOV word order in ordinary prose, although other word orders were employed, such as in poetry, enabled by inflectional marking of the grammatical function of words. However, word order in the modern Romance languages generally adopted a standard SVO word order. Fragments of SOV word order still survive in the placement of clitic object pronouns (e.g. Spanish yo te amo "I love you").

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