Re: smallest ANCIENT non-bird dinosaur - was what I was asking

[evelyn sobielski <koreke77@yahoo.de>]

--- "T. Michael Keesey" <keesey@gmail.com> schrieb:

> On Thu, May 8, 2008 at 11:07 AM, David Marjanovic
> <david.marjanovic@gmx.at> wrote:
> >
> > ----- Original Message -----
> > From: "Adam" <adam@crowlspace.com>
> > To: "Dinosaur Mailing List" <dinosaur@usc.edu>
> > Subject: Re: smallest ANCIENT non-bird dinosaur -
> was what I was asking
> >
> >> I've had interesting reactions when trying to
> >> explain how 10% of all the people alive 1,000
> years ago became ancestors
> >> to everyone alive, and 90% didn't. That kind of
> shocks people.
> >
> > Is it even true? Or are you only talking about
> mitochondria or Y
> > chromosomes?

If they still do it the mtEve/YAdam way (by lineage
coalescence time estimation), it's impossible to
arrive at any estimate at all. Those lineages can only
be traced back unbroken, so the "mitochondrial Eve" is
the *only* woman of her time who was lucky enough to
produce an *unbroken* line of daughters. Others may
have descendants living today, but it's simply not
traceable this way as soon as the unbroken line of
daughters/sons ends.

One could arrive at some reasonable estimate, but
genetics won't really help. You'd need to figure out
reproduction and mortailty rates per (sub)population.
One could use populations with restricted mating -
nobility, kohanim, druze etc - as a guideline; to what
degree the rest of the world mated nonrandomly can be
established by comparison.

That being said, it is not unlikely at all (though
nobody has checked) that the
great-great-...-grandfathers of, say, Leonard Cohen,
Ethan Coen and Walter Kohn were quite closely related
(and *perhaps* one and the same person) about 3500
years ago. But it's very much an exception; the case
of Jewish kohanim descendants combines
better-than-average ability to trace matrilinear (via
religion) and patrilinear (via name/job) descent.


Regards,

Eike


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