Re: Common ancestry?

On Sun, 30 Mar 2008 18:53:42 -0500, Jim Casey <seamus@xxxxxxxxxxxxxx>
wrote:
... It starts
with some common ancestry between great grandparents on Dads side and
great great grandparents on the dam side and gets more common from
there. Is this pretty typical in the horse world, or should I worry?
***
Normal. Actually less crossing than normal. There are no crosses until
the fifth generation back. You and I are most likely more "inbred" than that.

The supposed horrors of inbreeding are exaggerated, anyway. It's a problem
only in families that have recessive bad genes.

- Jim

Checking the numbers....
Assume it takes 25 years to produce TWO offspring,
then working back,
these two persons had
TWO parents, (25 yrs ago)
FOUR grandparents (50 yrs ago)
EIGHT greatgrandparents. (75 yrs ago)

Let's suppose we have been reasonably modern design hominids for
100,000 years (that's a low-ball estimate), then we are talking about
4000 generations.
So just for fun, let's work out the number of progenitors for 100%
outbreeding.
For simplicity, we will suppose there have always been 7 billion
people alive at one time (which is a way high-ball estimate)
How many generations back to reach the entire Earth population as
ancestors? That would be 2^33 = 7000,000,000. (roughly)

Oh! That's just 33 generations.
But we said there have been possibly 4000 generations.
It looks like 3rd, 4th and 5th cousins have often married in the
past.....

Brian W
.

Relevant Pages

  • Re: Common ancestry?
    ... with some common ancestry between great grandparents on Dads side and ... great great grandparents on the dam side and gets more common from ...
    (rec.equestrian)
  • Re: Common ancestry?
    ... with some common ancestry between great grandparents on Dads side and ... great great grandparents on the dam side and gets more common from ...
    (rec.equestrian)