African admixture in Europe - Wikipedia. African admixture in Europe refers to the Eurasian presence of humangeneticpolymorphisms that are considered to be evidence for movements of people from Africa to Eurasia in both the prehistoric and the historical past. The Nile River valley, which runs from East Africa to the Mediterranean Sea, could have served as a bidirectional corridor in the Sahara desert, allowing communication between Sub- Saharan Africa and the peoples of Eurasia. According to the leading evolutionary theory of human origins, known as the Out of Africa theory, anatomically modern humans first emerged in Africa 1. All non- Africans are descended from at least one group of humans who migrated out of Africa into western Asia 5. Remains of the first modern humans in Europe, the Cro- Magnon, were first found in southern Italy, and this group may have completely replaced the previous inhabitants, the Neanderthals, or absorbed them by interbreeding. Cro- Magnons were in the Middle East (today's Lebanon) by 4. Europe by 4. 0,0. By 3. 0,0. 00 years ago, the Cro- Magnon people had populated much of Europe. This, however, was not the last major human migration into Europe, and this paleolithic population was to some extent replaced by later migrations, to be discussed below. Duration within refuges. It is believed that human populations retreated south to warmer regions near the Mediterranean. Refuges during this period are believed to have been in Iberia, the Balkans, and Italy. After the Last Glacial Maximum, when the European climate warmed up, the refuges are thought to have been the source from which Europe was repopulated. African lineages that had been introduced into the Iberian refuge would have then dispersed all over Europe with the northward expansion of humans.
This could explain the presence of genetic lineages in eastern Europe and as far north as Russia that appear to have prehistoric links to northwestern and western Africa (see mt. DNA). The societies that first made the change to agriculture are believed to have lived in the Middle East around 1. BCE. Agriculture was introduced into Europe by migrating farmers from the Middle East. The latter group was widely semi- sedentary even before the introduction of agriculture. An important migration from North Africa across the Sinai also appears to have occurred before the formation of the Natufian. The genetic effect of this period on modern European populations is the subject of discussion (see below). In more recent history, the peoples of Europe and Africa came into contact during the exploration and colonization of Africa and as a consequence of the Atlantic slave trade. The most influential factors affecting human genetic variation are founder effects and isolation by distance. Several generations after the population has expanded, individuals will still possess the limited gene pool of the founders. Therefore, founder effects result in a loss of genetic diversity. Pique Your Curiosity With Black Meetups. This online dating network is a perfect online hangout club for folks who’re into dating within a black community. At Single Pen Pals.com you really can find a woman or man for dating, romance or friendship. A high quality site that protects your privacy. Genetic evidence suggests that the Out of Africa migration involved only small numbers of individuals. The African migrants carried a small subset of the prehistoric African genetic diversity, resulting in a founder effect on the non- African population. As humans spread across the globe populating Eurasia, Australia, and the Americas, there were several founder effects. As a result of these serial founder effects, genetic diversity tends to decrease with distance from Africa. According to this model, populations that live near one another are more likely to exchange mates than populations that live farther apart. As a result, populations that live near one another are genetically more similar than populations that live far apart. Percentage genetic distances among major continents based on 1. It is based on the principle that populations that share similar frequencies of a trait are more closely related than populations that have different frequencies of a trait. The genetic distance between two populations increases linearly with the geographic distance between them, due to isolation by distance and serial founder effects. When admixture occurs between populations, the genetic distance between the two populations is reduced. Cavalli- Sforza (1. Africa; Area: 30,370,000 km 2 (11,730,000 sq mi), 2nd: Population: 1.2 billion (2016, 2nd) Population density: 36.4/km 2 (94/sq mi) Demonym: African: Countries. This vintage, open-cockpit biplane, a Boeing-Stearman PT-13D Kaydet, c. 1944, was used at Alabama’s renowned Tuskegee Institute to train African American pilots for. Never shy to step into hot topics that affect real South Africans, here’s Nando’s latest advert as another controversial week in South Africa comes to an end. Table on the right). All non- African populations are more closely related to one another (i. This is consistent with a founder effect on the non- African population in that only a few individuals participated in the initial Out of Africa migration. The largest genetic distances observed are between Africa and Oceania and between Africa and the Americas. This is consistent with the isolation by distance and serial founder effects. Cavalli- Sforza (1. Sub- Saharan Africa and Europe is anomalously lower than it would be if the two populations had been evolving independently. The study suggests that the lower genetic distance between Europe and Africa can be explained by genetic admixture. Defining African admixture. Some DNA polymorphisms are shared by Europeans, West Asians, North Africans and Sub- Saharan Africans. Examples of such variants include the y- chromosomalhaplogroup E1b. M1. Consequently, the definitions of . Due to prehistoric migrations in and out of Africa, North African populations tend to exhibit allele frequencies that are intermediate between those of Sub- Saharan Africa and those of Eurasia. One clade of haplogroup U, namely U6a. Africa back into Europe. Other lineages are known to have moved from Europe directly into Africa, for example mitochondrial haplogroups H1 and H3. E1b. 1b. 1 lineages are found throughout Europe but are distributed along a south- to- north cline, with an E1b. Balkans. In a sample of European males, Cruciani et al. The timing of this movement has been given widely varying estimates. During the Bantu Expansion, people carrying haplogroup E (not including E1b. Sub- Saharan Africa from their homeland near the present- day border between Nigeria and Cameroon. The haplogroup most often associated with this expansion is E1b. African male gene pool. The presence of E1b. Africa can typically be associated with events that occurred after the Bantu Expansion, such as the Moorishoccupation of Iberia or the trade in African slaves. In much of Europe, frequencies of E lineages which are not E1b. For example, Cruciani et al. E1b. 1a is closely related to E1b. Europe. E lineages that are not E1b. E1b. 1b could therefore reflect either a recent expansion associated with E1b. E1b. 1b. For example, haplogroup E1a lineages have been detected in Portugal (5/5. The authors suggest that this distribution is consistent with a prehistoric migration from Africa to Iberia, possibly alongside mt. DNA haplogroup U6. Haplogroups A and B are thought to have been the predominant haplogroups in central and southern Africa prior to the Bantu Expansion. Currently these haplogroups are less common than E lineages. In a sample of 5,0. African men, haplogroup A had a frequency of 5%. Haplogroup A has rare occurrences in Europe, but recently the haplogroup was detected in seven indigenous British males with the same Yorkshire surname. This haplogroup, in Italy, is represented by E- M7. E- M1. 23 and E- M8. Figure 3). Another subclade, E3b. M8. 1 is associated with Berber populations and is commonly found in regions that have had historical gene flow with northern Africa, such as the Iberian Peninsula, the Canary Islands, and Sicily. That's the highest frequency observed in Europe to date. According to a study in 2. Cerezo et al., about 6. European L lineages most likely arrived in rather recent historical times (Romanization period, Arab conquest of the Iberian Peninsula and Sicily, Atlantic slave trade) and about 3. L mt. DNAs form European- specific subclades, revealing that there was gene flow from Sub- Saharan Africa toward Europe as early as 1. In both countries, frequencies vary widely between regions, but with increased frequencies observed for Madeira (insular Portugal), southern Portugal, C. Madeira and the Azores), L haplogroups constituted about 1. Madeira, significantly more than in the Azores. The authors suggest that this pattern indicates that most of the Sub- Saharan L lineages entered Iberia in prehistoric times rather than during the slave trade. According to Pereira et al. They suggest this pattern is more compatible with a recent arrival of these lineages after slave trading began in the 1. According to the study, alternative scenarios that invoke much older and demographically more significant introductions (Gonz. The remains date to between the 1. The frequency of Sub- Saharan lineages detected in the medieval samples was 1. Priego de Cordoba. The authors suggest the Muslim occupation and prehistoric migrations before the Muslim occupation would have been the source of these lineages. The highest frequencies of Sub- Saharan lineages found so far in Europe were observed by . Though a high diversity of African mt. DNA lineages have been detected, few lineages have accumulated enough mutations in Europe to form monophyletic clusters. L1b, L3b and L3d had matches with West African populations, indicating that these lineages probably entered Europe through Iberia. One lineage, L2a. Europe in prehistoric times. This clade was possibly related to L2a. Ashkenazi heritage from France, Germany, Poland, Romania and Russia. L2a lineages are widespread throughout Africa; as a result, the origins of this lineage are uncertain. The origins of haplogroup M1 have yet to be conclusively established. A 2. 01. 5 study found that a prehistoric episode would be the main contributor to the sub- Saharan presence in Mediterranean Europe and Iberia . Green Bay Packers fans have their own dating site(Jeff Hanisch- USA TODAY Sports)If you’re a Green Bay Packers fan looking for love, Green. Bay. Packers. Lovers. These days, dating websites are all the rage. From Tinder to Match. Coffee Meets Bagel, singles everywhere are finding their partners on the Internet. One thing that can sometimes be a deal breaker in relationships though is which team you root for. That’s why this new site completely dedicated to finding “diehard” Packers fans other Packers fans to date is a great idea.(Kelley L Cox- USA TODAY Sports)From Fox Sports: “Packers Backers alike will enjoy the site,” founder Kelly Davis said in a press release. And there are already success stories.(Jeff Hanisch- USA TODAY Sports)(Thanks to Awful Announcing for sharing.).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
August 2017
Categories |