In article <Pine.3.05.9504171453.C8530-b100000 at mcz>, dmw at MCZ.HARVARD.EDU (Daniel Weinreich) writes:
|> This morning I asked how many rounds of DNA replication per generation
|> occur in mammalian germ lines. I further speculated that if the Y-linked
|> clock runs faster it must be the case that male germline cells undergo
|> more rounds of DNA replication per generation than do female germline
|>|> An authority on precisely the question of Y-linked mammalian clock rates,
|> who cites several references regarding the number germline DNA replication
|> per generation in mammals kindly writes as follows:
|>|> >From GSBS005%UTSPH.THENET at lib.tmc.edu Mon Apr 17 13:58:34 1995
|> >Date: Mon, 17 Apr 95 12:48:13 CDT
|> >From: GSBS005%UTSPH.THENET at lib.tmc.edu|> >To: dmw at mcz|> >
|> >My colleagues and I have published some data on these issues.
|> >The references can be found in the following papers and the references
|> >therein: Shimmin et al. Nature 362, 745, 1993; Chang et al. PNAS 91, 827,
|> >1994; and Chang and Li, J. Mol. Evol. 40, 70, 1995.
|> >Best regards, Wen-Hsiung Li
|>|> Happy reading everyone, and thank you Dr. Li.
There is another explanation for the observed discrepancy in these
papers: DNA in sperm is methylated, while in ova it is not. This
would mean that genes on the Y chromosome would experience more
C to T transitions independently of any effect that may be caused
by cell division.
Ingrid Jakobsen at anu.edu.au
Human Genetics Group
John Curtin School of Medical Research
Australian National University.
P.O. Box 334 Canberra, ACT 2601