[Jacob-list] Inbreeding--linebreeding--whatever you call it

[Hobsickle at aol.com]

Thanks for the details--it sounds like an interesting flock, and perhaps on 
that I would like to get individuals from.  Inbreeding does tend to produce 
(as I mentioned) individuals which are homozygous (true) for random traits, 
and this is most obvious for recessive traits.  This also illustrates two 
other genetic principles, i.e., founder's affect and genetic drift.  Starting 
with, at best, 3 different sets of genes (1@ from the ewes and ½ @ from the 
sire of the rams--assuming that each sibling got a unique ½ from each parent, 
which isn't probable) the gene pool was already very small, meaning some 
traits probably weren't carried into the flock start with.  Then the 
randomness of gene segregation likely removed other genes (this is genetic 
drift).  All in all, it doesn't surprise me to hear that traits like 'absence 
of ticking' and lilac were prevalent.

It sounds like this pretty close to a situation where a flock could have 
adapted genetically to its environment.  (To be clear, inbreeding under 
normal circumstances is not going to produce a sheep that is better for the 
specific farm.)

Also I need to mention that the Butcher's selection was likely not random.  
(I can't easily imagine anyone walking into a flock and grabbing the 
attractive animals for slaughter.  I also can't imagine a flock owner not 
giving at least general instructions to the butcher.)  So to say that this 
flock did better by not selecting "registry traits" is not necessarily 
substantiated.  By definition phenotypical traits (though influenced by 
environment, etc.) are a result of genotype.  In this case, the effects of 
the founder's affect, genetic drift, the butcher, and possibly natural 
selection can account for every phenotypic result I've heard about in this 
flock.  These circumstance are too unique to allow too many specific 
inferences.

-Dan

PS Any lilac ewes available from this flock?

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