[Jacob-list] Fw: What is lilac?

[Grose]

Here's a communication with Dr. Sponenberg that I thought y'all might be interested in. In our flock, lilacXlilac=lilac, lilacXlilac carrier= 50% lilac and 50% black, etc. just like we would expect. I think I will repeat this test cross [on purpose this time]. It would be helpful though if others would try some test crosses to other white breeds and to mouflan or Barbados.                     Neal Grose
----- Original Message ----- 
From: Phil Sponenberg 
To: Grose 
Sent: Thursday, August 09, 2001 3:42 PM
Subject: Re: What is lilac?


oooh no, this is indeed interesting. Some lilacs appear to be Agouti locus patterns. Yours cannot be, and so is interesting. This might be a brown locus allele segregating, since your crosses indicate something like that. Not all lilacs are created equal. What happens when you cross lilac to lilac in your flock?

Phil


  Dr. Sponenberg,
  A topic has come up on the jacob-list that has drawn a great deal of interest. We have had "lilac" sheep in our flock for some time. About 2 years ago, MaryEllen Hansson wrote to you concerning an impromptu test cross between a lilac ram and some white Cotswold/Finn/Lincoln/Finn ewes on our farm. ALL the resulting lambs[20] were black with white markings [they ranged from 95% to 50% black]. I have to assume that even if all the ewes were heterozygous white/black that some of the lambs would have turned up white or lilac had they not inherited a Jacob dominant black allele. What I recall is that at the time, you indicated that the lilac essentially "masked" the expression of black. "Black" and "lilac" appear to have a simple dominant/recessive relationship. If the lilac allele does not alternate with black at the "extension" locus could it be a subset of "extension" or would it be at a separate locus where the dominant condition is not expressed?
  My wife, Louise, assures me that the color we see as lilac is a corruption of yellow. In trying to recreate it on the computer paint program the closest that I have been able to come to this so far is red 49,green 21, blue 15, hue 8, saturation 128, and lum 30. The true color is slightly more yellow and blue and more saturated. The legs and horns on these guys appear saturated brown, one shade lighter than the "blacks".
  [?] What does lilac knock-out of black to get this color? When our sheep are sun scorched, the lilac and black wool is almost the same on the tips.
  Thank you very much for your attention to this fascinating yet useless field of study.
  Neal Grose





D. Phillip Sponenberg, DVM, PhD
Director of Student Affairs
Professor, Pathology and Genetics
Virginia-Maryland Regional College of Veterinary Medicine
Virginia Tech
Blacksburg, VA 24061
USA

e-mail: dpsponen at vt.edu
phone: 1-540-231-4805
fax: 1-540-231-6033 
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