312
H.C. Harpending and E. Eller
must wait for identification of the genetic basis of skin color and other aspects of
physical appearance for a critical test.
If there is any validity to our hypothesis, other similarities in appearance that
anthropologists in the early part of this century described might in fact be real
signatures of ancient population expansions and movements that should be the
basis for archaeological work. The idea of a Yedda-Australian-Ainu connection
and the similarities of Negrito peoples around the Pacific rim and African Pygmies
are examples of such hypotheses.
4 Conclusion
We have outlined some of the more interesting problems in the history of our species and considered how various categories of data may help resolve them.
It is widely accepted (but not necessarily correct!) that modern humans appeared in Africa and expanded from this homeland within the last 100 000 or so
years. While the northern branch is readily apparent in the archaeological record of
Europe and west Asia, the early appearance of humans in Australia at 40 000 to
50 000 years ago suggests that there was a southern branch of the human exodus
that roughly followed the Indian ocean coast. The hypothesis of a southern branch
receives support from the distribution of language macro-families in the Old World
and from the presence of modern humans in Tasmania. This island had been separated from Australia for thousands of years before the other candidate for the peopling of Australia, the event 5000 years ago when dogs and microliths appeared
and population increased by roughly a factor of ten. The suprising implication of
the model of a separate southern branch is that Mode 4 technologies - fancy blade
tools and worked bone - are not a distinctive signature of new human cognitive
capacities but mere signs of male leisure in a new rather empty ecosystem.
Spectacular advances in typing neutral markers have provided large numbers of
markers from various human popUlations. These markers should be free of the
ascertainment bias that made comparisons of genetic diversity across populations
unreliable. These markers show a diversity cline away from Africa and a pattern of
population difference that looks like rather smooth isolation by distance but with
marked clumping into groups that are rather like traditional "major races." More
populations need to be sampled before this clumping can be carefully evaluated.
Populations that have seemed on other grounds to be distinct from their neighbors turn out not be distinct when we look at neutral markers. Bushmen of southern
Africa, for example, appear as simply another African population. We suggest that
other marker categories like language and external appearance might provide a
deeper look at human history. These share with the Rh system the property that
selection should favor the common type or, in the case of sexually selected appearance, some exaggeration of the common type. Under such dynamics they would
"resist" the effects of gene immigration while neutral markers should "blend". We
H.C. Harpending and E. Eller
must wait for identification of the genetic basis of skin color and other aspects of
physical appearance for a critical test.
If there is any validity to our hypothesis, other similarities in appearance that
anthropologists in the early part of this century described might in fact be real
signatures of ancient population expansions and movements that should be the
basis for archaeological work. The idea of a Yedda-Australian-Ainu connection
and the similarities of Negrito peoples around the Pacific rim and African Pygmies
are examples of such hypotheses.
4 Conclusion
We have outlined some of the more interesting problems in the history of our species and considered how various categories of data may help resolve them.
It is widely accepted (but not necessarily correct!) that modern humans appeared in Africa and expanded from this homeland within the last 100 000 or so
years. While the northern branch is readily apparent in the archaeological record of
Europe and west Asia, the early appearance of humans in Australia at 40 000 to
50 000 years ago suggests that there was a southern branch of the human exodus
that roughly followed the Indian ocean coast. The hypothesis of a southern branch
receives support from the distribution of language macro-families in the Old World
and from the presence of modern humans in Tasmania. This island had been separated from Australia for thousands of years before the other candidate for the peopling of Australia, the event 5000 years ago when dogs and microliths appeared
and population increased by roughly a factor of ten. The suprising implication of
the model of a separate southern branch is that Mode 4 technologies - fancy blade
tools and worked bone - are not a distinctive signature of new human cognitive
capacities but mere signs of male leisure in a new rather empty ecosystem.
Spectacular advances in typing neutral markers have provided large numbers of
markers from various human popUlations. These markers should be free of the
ascertainment bias that made comparisons of genetic diversity across populations
unreliable. These markers show a diversity cline away from Africa and a pattern of
population difference that looks like rather smooth isolation by distance but with
marked clumping into groups that are rather like traditional "major races." More
populations need to be sampled before this clumping can be carefully evaluated.
Populations that have seemed on other grounds to be distinct from their neighbors turn out not be distinct when we look at neutral markers. Bushmen of southern
Africa, for example, appear as simply another African population. We suggest that
other marker categories like language and external appearance might provide a
deeper look at human history. These share with the Rh system the property that
selection should favor the common type or, in the case of sexually selected appearance, some exaggeration of the common type. Under such dynamics they would
"resist" the effects of gene immigration while neutral markers should "blend". We