Expert: John Shea - 4/2/2004

Question
John - there is no Genetics expert yet so here I am again.
In the Nova programme 'Children of Eve' (broadcast 27 Jan 1987) Douglas Wallace, Biochem, Emory University, Atlanta, asserted that mitochondrial DNA found in Asian human populations was the DNA most similar to DNA of other primates. If this finding still holds, any idea what the prevailing conclusion is, if any.
Also, what of the reported unexpected consistencies between specifically Asian sapiens skull morphologies and corresponding features of Asian Homo Erectus skulls - should we read anything significant into this apparent correspondence?
Is there any chance Homo Erectus was actually an early strain of our own species - is this still an open question or is it cast in stone?
Thanks - Tony

Answer
Dear Tony,
All that I have read on this lately suggests all living humans are about equally distantly related to non-human primates and our limited sample of non-Homo sapiens fossils (i.e., Neandertals).
Alan Thorne, Milford Wolpoff and others have argued that similar morphologies among Indonesian H. erectus skulls and those of recent Australian Aborigine populations implies evolutionary continuity between the two.  I am very skeptical about this interpretation because the precise mechanisms of human skull growth remain poorly understood.  It is conceivable, indeed likely, that similarities between Homo sapiens and Homo erectus skulls may arise from homoplasy (similar shapes arising from different genetic and mechanical processes).  For what it's worth, the archaeological record suggests that the behavior of Homo erectus was very different from that of any Homo sapiens populations (more different that between any pair of Homo sapiens populations).  I would be very surprised if these hominids had anything to do with each other (other than maybe to compete in some way) IF they every met face-to-face (for which there is no evidence whatsoever).
Homo erectus (in the broad sense, and more particularly the African variant) is probably ancestral to Homo sapiens, but there are chronologically interemediate hominid species (Homo heidelbergensis, Homo helmi) whose ancestral status need to be sorted out.  Right now, one of the big problems for such a sorting is that apart from the rich sample from Atapuerca, Spain, we lack large numbers of relatively complete fossils from contexts dating 100-500 Ka in Africa and South Asia.
I hope this answer helps.
Cheers,
John Shea