[Jacob-list] Yet another lilac hypothesis

[Hobsickle at aol.com]

Everyone seems to have a pet theory on lilacs, so I guess that I'll add 
mine--for whatever it's worth.

I believe that there is three (maybe more, but no less) loci controlling the 
black/lilac colorations.  (For simplicity I am ignoring spotting, ticking, 
greying, and other color variations.)  Those three loci are: the "dominant 
black" extension locus (E), the agouti locus (A), and the brown locus (B).  
Grey lilac being produced by the agouti grey (Ag) when a wild allele (E+) 
resides at the extension locus, chocolate being produced by the homozygous 
BbBb, and a tanish being produced by a combination of grey and brown.  This 
said, I suspect that the different colors (I am using descriptive color 
names, rather than sheep color nomenclature) are produced by the following 
genotypes:

Black (non-carriers): 
EbEbA?A?B+B+ 
EbE+A?A?B+B+

Grey lilac:
EbE+AgA?B+B+

Chocolate lilac:
EbEbA?A?BbBb
EbE+A?A?BbBb

Tanish lilac:
EbE+AgA?BbBb

Black (lilac carriers):
EbEbAgA?B+B+
EbE+AgA?B+B+
EbEbA?A?B+Bb
EbE+A?A?B+Bb
EbEbAgA?B+Bb
EbE+AgA?B+Bb

I am somewhat unclear as to what Jacobs might normally have at the agouti 
locus, hence the A?.  Considering the comments of David Kinsman quoted by 
Juliet, if Hebridean sheep picked up the dominant black (Eb) from Jacobs in 
the parks of England, then it sure seem reasonable that Jacobs could have 
picked up the recessive black (Ab) from the Hebridean in those same parks.  
If in fact that is true, it would help to hide the presence of wild extension 
alleles (E+) in the Jacob genotype.

-Dan
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