Additional Support for Out of Africa

As I understand it, there are two main competing models for the origin of modern humans. As Science News puts it:

The origin of modern humans is a debated topic. One leading theory postulates that the ancestors of all modern humans originated in East Africa and then left the continent around 100,000 years ago. From there, they colonized the world, displacing previously established hominids such as Neanderthals in Europe. The best evidence so far for this theory is the higher genetic diversity (and thus inferred older age) of the African population compared to populations from other continents.

A minority theory proposes that modern humans evolved simultaneously in different regions of the world from populations of archaic humans and that both contributed to the current human genetic pool. The modern Homo sapiens species is, therefore, seen as the result of the sharing of genes and behaviors between archaic and modern humans.

For more information see this.

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A new paper has been published that supports the leading model. Here is the abstract:

A leading theory for the origin of modern humans, the ‘recent African origin’ (RAO) model, postulates that the ancestors of all modern humans originated in East Africa and that, around 100,000 years ago, some modern humans left the African continent and subsequently colonised the entire world, displacing previously established human species such as Neanderthals in Europe. This scenario is supported by the observation that human populations from Africa are genetically the most diverse and that the genetic diversity of non-African populations is negatively correlated with their genetic differentiation towards populations from Africa.

Using a dataset of 377 autosomal microsatellite loci from 51 populations, the authors looked at the correlation between genetic diversity and geographical distance from Ethiopia, where the oldest human remains have been found. They found a pretty smooth negative correlation between the two. That is, the farther away the population sampled was from Ethiopia, the less genetic diversity was found.

Now this certainly is not my field and I am not qualified to critique the paper, but it does seem to support the leading model. Also in the news summary one of the authors says, "The lack of stark differences suggests that humans cannot be classified in discrete ethnic groups or races on a genetic basis."