Define out of africa thesis

In the most common version of Out of Africa, modern humans are considered a new species, with negligible gene-flow mating between the migrating African people and the indigenous archaic groups.

Map of early diversification of modern humans according to mitochondrial population genetics see: The first lineage to branch off from Mitochondrial Eve is L0. It is also found among the Mbuti people. The macro haplogroups M and Nwhich are the lineages of the rest of the world outside Africa, descend from L3.

L3 is about 84, years old and haplogroup M and N are about 63, years old. If there had been several migrations, one would expect descendants of more than one lineage to be found. L3's female descendants, the M and N haplogroup lineages, are found in very low frequencies in Africa although haplogroup M1 populations are very ancient and diversified in North and North-east Africa and appear to be more recent arrivals.

A possible explanation is that these mutations occurred in East Africa shortly before the exodus and became the dominant haplogroups after the departure through the founder effect. Alternatively, the mutations may have arisen shortly afterwards. Southern Route and haplogroups M and N[ edit ] Results from mtDNA collected from aboriginal Malaysians called Orang Asli and the creation of a phylogenetic tree indicate that the hapologroups M and N share characteristics with original African groups from approximately 85, years ago and share characteristics with sub-haplogroups among coastal south-east Asian regions, such as Australasia, the Indian subcontinent and throughout continental Asia, which had dispersed and separated from its African origins approximately 65, years ago.

This southern coastal dispersion would have occurred before the dispersion through the Levant approximately 45, years ago. Evidence of the coastal migration is thought to have been destroyed by the rise in sea levels during the Holocene epoch. The group that crossed the Red Sea travelled along the coastal route around Arabia and Persia until reaching India.

The indigenous people of the Andaman Islands also belong to the M lineage. The Andamanese are thought to be offshoots of some of the earliest inhabitants in Asia because of their long isolation from the mainland.

They are evidence of the coastal route of early settlers that extends from India to Thailand and Indonesia all the way to Papua New Guinea. The proportion of haplogroup M increases eastwards from Arabia to India; in eastern India, M outnumbers N by a ratio of 3: Crossing into Southeast Asia, haplogroup N mostly in the form of derivatives of its R subclade reappears as the predominant lineage.

Human genetic variation and Human genetic clustering A study of African, European and Asian populations, found greater genetic diversity among Africans than among Eurasians, and that genetic diversity among Eurasians is largely a subset of that among Africans, supporting the out of Africa model.

Based on this evidence, the study concluded that human populations encountered novel selective pressures as they expanded out of Africa. According to this study, Papua New Guineans continued to be exposed to selection for dark skin color so that, although these groups are distinct from Africans in other places, the allele for dark skin color shared by contemporary Africans, Andamanese and New Guineans is an archaism.

A study by Gurdasani et al. For this reason, JCV has been used as a genetic marker for human evolution and migration. From this Shackelton et al. Admixture of archaic and modern humans[ edit ] Main article: Archaic human admixture with modern humans Evidence for archaic human species descended from Homo heidelbergensis having interbred with modern humans outside of Africa, was discovered in the s.

This concerns primarily Neanderthal admixture in all modern populations except for Sub-Saharan Africans but evidence has also been presented for Denisova hominin admixture in Australasia i. AterianBaradostianand Microlith In addition to genetic analysis, Petraglia et al.

He proposed that the stone tools could be dated to 35 ka in South Asia, and the new technology might be influenced by environmental change and population pressure. The cladistic relationship of humans with the African apes was suggested by Charles Darwin after studying the behaviour of African apesone of which was displayed at the London Zoo.

Haeckel argued that humans were more closely related to the primates of South-east Asia and rejected Darwin's African hypothesis.

In each great region of the world the living mammals are closely related to the extinct species of the same region.

It is, therefore, probable that Africa was formerly inhabited by extinct apes closely allied to the gorilla and chimpanzee ; and as these two species are now man's nearest allies, it is somewhat more probable that our early progenitors lived on the African continent than elsewhere.

But it is useless to speculate on this subject, for an ape nearly as large as a man, namely the Dryopithecus of Lartet, which was closely allied to the anthropomorphous Hylobatesexisted in Europe during the Upper Miocene period; and since so remote a period the earth has certainly undergone many great revolutions, and there has been ample time for migration on the largest scale.

Almost fifty years later, Darwin's speculation was supported when anthropologists began finding fossils of ancient small-brained hominins in several areas of Africa list of hominina fossils. The hypothesis of recent as opposed to archaic African origin developed in the 20th century.

The "Recent African origin" of modern humans means "single origin" monogenism and has been used in various contexts as an antonym to polygenism. The debate in anthropology had swung in favour of monogenism by the midth century.The Out of Africa Theory is a widely renown theory describing the origin of the human race and their early dispersal throughout the world.

According to this theory, humans have a monogensis, or a single and common origin; Africa. The Out of Africa (OoA) or African Replacement Hypothesis is a well-supported theory that argues that every living human being is descended from a small group of Homo sapiens (abbreviated Hss) individuals in Africa, who then dispersed into the wider world meeting and displacing earlier forms such as Neanderthals and Denisovans.

The "Out of Africa" thesis states that Homo sapiens sapiens emerged in Africa and then migrated from there, and is the most widely accepted theory by scientists, while the multiregional thesis states homo sapiens sapiens emerged simutaneously throughtout the world and descended from earlier hominid groups that had already left Africa.

The “Out of Africa” hypothesis is an evolutionary theory of modern human origin that posits that modern humans arose in the late Pleistocene, about ,–, years ago, in Africa.

There are different versions of “Out of Africa,” but its major tenet is that modern humans originated as. Africa, a land of beautiful and fascinating sceneries, a land of rich culture, a land where wild and untamed animals reside, a land blessed with natural resources but when som eone talks about Africa the first thing comes in mind is a battlefield, killing of innocent people, poverty, lack of food, dictatorship.

The "Out of Africa" theory is used in paleoanthropology to explain the geographic origin of modern day humans, and it asserts that modern humans evolved recently in Africa and migrated out into Eurasia, replacing all the regions that were once populated by lineages connected to Homo erectus.

In the.