GENEALOGY-DNA-L ArchivesArchiver > GENEALOGY-DNA > 2006-10 > 1161090776
Subject: Re: [DNA] Population genetics: DNAs from the European NeolithicFULL TEXT
Date: Tue, 17 Oct 2006 09:12:56 EDT
In a message dated 10/16/2006 6:47:24 AM Pacific Daylight Time,
> But in this article (first page, last paragraph) what does
> "ascertainment bias" mean?
> Apparently "ascertainment bias" in the choice of polymorphic loci can
> also generate clines.
> >ljcrain wrote:
> >Population genetics: DNAs from the European Neolithic
It's defined at Wikepedia as "an error in the way scientific research is
conducted such that a false association is produced by unintentional non-random
sampling of two study populations."
In ancient DNA studies, one example of ascertainment bias could occur if the
remains available for study are available only because of different burial
practices in a certain segment of the population.
Jobling's article "The Human Y Chromosome: An Evolutionary Marker Comes of
Age" has a sidebar about ascertainment bias and Y chromosome markers. I liken it
to the parable of the drunk looking for his car keys under the streetlight
because it was dark where he dropped them. We can only study markers we already
know about from previous research in limited populations.