[Jacob-list] Re.Lilac Question

[WenlochFrm at aol.com]

In a message dated 8/4/01 11:12:51 AM Eastern Daylight Time, 
NLGrose at Yadtel.net writes:


> The result was almost 20 lambs that were from one white Cots parent and one 
> lilac Jacob. ALL lambs were born black with white markings. They had to 
> inherit a dominant black Jacob allele. "Lilac" is a masking gene/s that has 
> to have 2 in order to fully cover the dominant black. This may explain the 
> lilac around the eyes. 
> I did notice that this year it was fairly difficult to tell the lilacs from 
> the blacks at birth.
>                                           
> 
I have to think about what you said. If it takes two lilac recessives to 
produce a lilac, then how could there be a Jacob dominant black involved? 
Could something have come from the Cotswold side? I know there are black 
Cotswolds. Would white be dominant over any recessive black in the background 
of your white Cots? Could that account for the all black lambs? OR???????? 
maybe something else is going on here. I have had some suspicions that it 
doesn't always take two lilac recessives to produce a lilac. A fair share of 
breeders have mentioned there surprise at getting a lilac, and that includes 
myself. When I brought the lilac ram into my flock, I didn't expect any lilac 
lambs because I didn't think any of the ewes had lilac in their backgrounds. 
And, none of them had the halo around the eye that I hear all of you talk 
about. Do you suppose it is possible that some of our b/w's are NOT dominant 
black and opening the way for one recessive lilac allele to express itself? 

>>
[I want to know more about pheo and eu, where can I find it?] I think that it 
is interesting, also, that in this group of lambs that the markings were so 
strong, I have previously seen references to the spotting gene/s as 
recessive. >>

There is a color genetics list you can subscribe to for starters. It is 
mostly Shetland and Icelandic breeders, but you can learn a lot from them. 
You can find it on Onelist, or maybe it's Yahoo now. They have an archive so 
just do a search on pheomelanin or eumelanin. Also, the Mendelian Color 
Inheritance is at:
http://www.angis.org.au/bin/Databases/BIRX/birx_doc?mis+1
Just keep adding 1 to the last digit to get to the next page.

And, Fred had a good article on pheo and eu last year in either the Spring or 
Summer issue of the Journal. If you ask him, he would probably send it to 
you. One of the things I remember is the test he mentioned to know whether 
wool is pheo or eu. Soak the wool in a cup of water with 1 tsp. of bleach 
added. If the wool fades, it's pheo. If not, it's eumelanine. Pheo is 
responsible for the tans/yellows and what some call the warm browns. I assume 
the grey/brown lilacs are pheos, but I think I will try the test anyway. 
Eumelanin are the blacks, black/browns and greys. But it gets more 
complicated by things (sorry, this isn't very scientific language) called 
receptors that control pheo and eu on the same sheep. I think what they are 
saying, too, is that a receptor can switch back and forth between pheo and eu 
giving different colors on the same follicle, but we don't have to be 
concerned with that in Jacobs. Follow the thread in the archived records and 
you can read it for yourself, because I'm not at all sure I have it right. 
 
Joan Franklin
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