Friday, April 21, 2006

OUT OF AFRICA HYPOTHESIS: MORE EVIDENCE?

Out of Africa hypothesis asserts that modern humans evolved relatively recently in Africa, migrated into Eurasia and replaced all populations which had descended from Homo erectus.

It is difficult to understand the out of Africa hypothesis. There are lot of questions that people have in mind. Like why the Homo erectus migrates out of Africa? Why is mankind split into distinct racial types? Through genetic evidence, lot of questions have been answered. It was shown that every living human being is descended from a small group in Africa, who the moved to the other parts of the world displacing earlier forms such as Neanderthal.

Beside the African eve hypothesis there is the multi-regional hypothesis which recently disagree with the African eve hypothesis. The multi regional hypothesis suggests that, modern humans evolved from outdated forms (such as Neanderthal and Homo erectus) con-concurrently in different regions of the world. This hypothesis is supported by physical evidence, such as the continuation of morphological characteristics between ancient and modern humans.

Researchers therefore reason that all living humans descend from Africans, some of whom migrated out of Africa to populate the rest of the world. If the mitochondrial analysis is correct, then because mitochondrial Eve represents the root of the mitochondrial family tree, she must have predated the exodus and lived in Africa.

Based on mitochondrial evidence, many researchers support the Out-of-Africa model. One finding not subject to interpretation is that the greatest diversity of mitochondrial DNA sequences exists among Africans. This diversity would not have accumulated, researchers argue, if humans had not been living longer in Africa than anywhere else. Analysis of Y chromosome sequences have corroborated the evidence that mitochondrial DNA has provided for an African origin for hominids.

Are humans originated in Africa and is there enough evidence? I think that based on the majority of anatomical, archaeological and genetic evidence we can conclude that the best explanation for the beginning of modern humans is the out of Africa that postulates a single, African origin for Homo sapiens.

1 Comments:

At 3:59 AM, Blogger Mbali Tyolo said...

Good Day! May you please explain the hypothesis (evidence) in terms of the mitochondrial DNA and Y-chromosomes, basically how they help the evidence of evolution

 

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