[Jacob-list] Re: Lilacs

[Neal and Louise Grose]

Dr. Sponenberg says that "lilac" is used for "not black" by Jacob breeders.

    The results that we have here from test crosses seem to be consistent with what Dan shows as a "Brown" series where dominant black is modified by a recessive at the brown locus. The action here is as though we are seeing partial albinism. [I floated this idea to Dr. Sponenberg, but he said it was highly unlikely that 'lilac' is at the albino locus (C). Yet another modifier!] Some sort of modification at the B locus makes more sense.
    Our Jacobs are clearly black (or "lilac"), but the tone has been described as "warm" by several who have more experience with color perception (have some artistic training). By this standard, Holsteins are "cool" black. This raises the possibility that the brown locus is "warming" the expression of black in these bloodlines.

    If a "chocolate lilac" (brown) were crossed to a "grey", since the brown retains the dominant black (unexpressed), then there is a chance that a black lamb can be produced. [EdEd,BbBb,AaAa X E+E+,B+B+,AgAg = EdE+,BbB+,AaAg ]

Neal Grose

PS: I found a picture a few months ago of a Corriedale X Cotswold X Finn wether that we had about 12 years ago that was black with a large, distinct brown saddle across on his back. Weird.
  ----- Original Message ----- 
  From: Hobsickle at aol.com 
  To: nlgrose at yadtel.net ; lambfarm at sover.net ; creaganlios at monad.net 
  Cc: jacob-list at jacobsheep.com 
  Sent: Monday, September 29, 2003 7:43 PM
  Subject: Re: [Jacob-list] Re: Lilacs


  1) Test crosses of "chocolate lilac" Jacob to both moorit and homozygous white are giving the same results...black lambs. (And in our case, piebald black and white lambs.)

  This together with some of today's other discussions leads to one of the serious problems in this whole color business--that is, there is no standardization of terms among Jacob breeders and no assurance that we are all using the terms the same way.  The literature describes black as ranging from black to "brown-black" and the browns ("moorits") as a range including milk chocolate, dark chocolate, and black-brown.  Brown-black...black-brown...where's the line??? (You, Neil, have commented the the "black" of Jacobs typically browner than the black of Holsteins.)  It is pretty pointless to discuss results of crosses if we're not all on the same page with our terms.  I'm not sure how to standardize it, but it does need to be standardized.


  2) If different lilac colors are the result of different combinations of genes, then occasionally we should have some funky results from crossing lilac to lilac. Has any one seen this?

  The punnett square at the address I sent yesterday lists all of the possible genotypes for the alleles suggested.  Nothing funky strikes me as the possible genotypes (ignoring shades) are black, grey, brown-grey, and brown.  The literature indicates that grey homozygotes are lighter than heterozygotes, so perhaps we can add "light" and "dark" to the list of grey-bearing phenotypes.  (This may explain why some lilacs fade so badly--maybe they are homozygous.)

  -Dan
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.pairlist.net/pipermail/jacob-list/attachments/20030929/8eb91967/attachment.htm