Genetics issues in ancient India

[Vidyasankar Sundaresan]

Steve Farmer <saf at SAFARMER.COM> wrote:

>It is important to note that mtDNA studies like this may not be
>as relevant to invasion/migration issues as studies of y-chromosome

mtDNA studies may not be relevant only to those who assume that
the incoming Aryans were all male, who took native female partners.
This assumption reveals more about the inadequacies of the theory
than about the inadequacies of mtDNA studies themselves. If the
incoming Aryans were a mixed population of males and females (as
I would expect them to have been), mtDNA studies will still have
important contributions to make.

>polymorphisms, which (in constrast to mtDNA studies) trace male
>and not female lineages. There are only a handful of y-chromosome

Both your stand and my response above rely on the current paradigm
that mtDNA is derived solely from the female line. This is, in turn,
based on the observation that in most species, sperm cells do not
contain mitochondria, or that if they do, mitochondrial material
is digested after fertilization of the ovum. This picture is now
becoming more complex. In some mollusc species, it is already well
accepted that mtDNA show bi-parental inheritance. Human sperm does
have mitochondria, and I am keeping an eye open for the possibility
that mtDNA lineages may not be solely maternal.

See, for example, the following papers that are only a year old.

Strauss, E. - Human genetics - mtDNA shows signs of paternal
influence, SCIENCE 286: (5449) 2436-2436 DEC 24 1999,

and

Gocke, C. D., Benko, F. A., Dodson, W., Rogan, P.K. -
Normal human sperm exhibit greater mitochondrial DNA (mtDNA)
heteroplasmy than ova. AMERICAN JOURNAL OF HUMAN GENETICS
65: (4) 1517 , Suppl. S OCT 1999

Of course, a complete picture of genetic inheritance will have to
come from studies of both mtDNA and Y-chromosome markers. Much
primary work remains to be done on Indian populations.

Vidyasankar