Re: RC: RE: Karahty (and Bloodlines in Arabs)

[CMKSAGEHIL@aol.com]

In a message dated 4/20/00 9:32:18 AM Pacific Daylight Time, 
bobmorris@rmci.net writes:

<< Realize we only went back five generations as anything further does not 
have
 immediate influence on performance. >>

That's only true when you are dealing with a diverse group of ancestors.  The 
vast majority of the horses that came up repeatedly in your study are 
actually quite closely related, which becomes obvious going back just a few 
more generations.  One stallion in particular (Mesaoud) often does not appear 
in modern pedigrees until one goes back 7 or 8 generations, but appears 
literally hundreds of times, so actually makes up a very high percentage of 
the pedigree.  I was shocked when I counted the number of times he appeared 
in the pedigrees of my own stallions, and then calculated the actual 
percentages of their pedigrees that he represents--it ranged from a low of 
12.4% to a high of 19.8%.  Furthermore (reference geneticists Michael and Ann 
Bowling for explanation if you don't grasp this), an individual has far more 
influence on a pedigree by appearing multiple times several generations back 
than he or she does by appearing fewer times up close (if he is represented 
by different ones of his offspring) because each different offspring has a 
different subset of the genes of that particular ancestor.  Mesaoud, for 
instance, appears in pedigrees in my own herd through over 20 of his 
offspring--each of which represents a "unique" half of his genetic material.  
(And my group is fairly representative of the Mesaoud influence in North 
America, I might add.)  To look at a more recent example of representing a 
particular ancestor--we've tried to represent Abu Farwa (among several other 
ancestors) in our program, and although since he is more modern than Mesaoud, 
it is difficult to find such a spread in one pedigree, he occurs through 24 
different offspring in our program.  In another 3 or 4 generations, he could 
well appear much the way that Mesaoud does in the current pedigrees.  Does 
that mean he would no longer be an influence?  Hardly!

The current study under discussion is interesting, but as Kris pointed out 
(and Salim concurred) it does not ask specific questions.  And as others have 
pointed out, it does not delineate possible differences between successful 
endurance horses and the North American gene pool at large.  Michael Bowling 
has done a random sample of relatively current stud books which he has used 
for several studies--it would be interesting to look at this list in context 
of that random sample, for instance.

Heidi