[Jacob-list] Color hierarchy

[Neal and Louise Grose]

Betty writes:
"If that's the case, then do you suppose that somehow
> there are two blacks, as Sponenberg has suggested, and one of them is the
> recessive black of other breeds, to which the lilac is dominant, and under
> the lilac is a recessive black, which comes out because event hough
> recessive, it is dominant to moorit?  If that's the case, then some of
your
> lambs ought to be lilac and some black and white, depending on which gene
> they get from mama, both of them being dominant over moorit Max.  If the
> dominant black were present, then the lilac wouldn't be expressed.  ANd
> other breeds have lost this dominant black, which would be dominant over
> white et al.  How's that grab  you?"

I think that color in sheep is a big mess. The more I look at things, the
more I need to look at more animals. I think that I will use Max next year
on a wider variety of sheep. It would be worthwhile to get other bloodlines
of lilac as well as the standard color sheep we have here to see the effect
on them. Several years ago, for lack of space, all the long wool sheep here
were bred to a lilac Jacob ram. About half of these ewes were 'silver' (the
color range in this group is from dark to oatmeal) and the rest were white.
We wound up with well over thirty black and white piebald lambs from this
cross. We have previously had several lilac ewes mistakenly bred to a white
long wool ram with the same results. This is more than a test cross on a two
sheep. SOMETHING is up here.

 I enjoyed reading Fred's comments last night, and to be honest, the
chemistry was a little beyond what I can figure out without making out a
diagram. What is becoming apparent is the hierarchy of genetics is not a
simple matter of A over b over c...and so forth, but there is a complicated
interaction between genes. This does not mean that it can not be figured
out. It may well be that it is not worth the effort. Beyond three equations
with three unknowns, I get fuzzy.

As breeders, we do not necessarily have to pay strict attention to the
scientific explanation. We can give preference to phenotype over genotype.
(You don't know how bad of a tick it gives me to say that.) However, we need
to acknowledge that we understand our lack of understanding. Jacob sheep
should still be DESCRIBED as black and white piebald sheep horned in both
sexes. As Fred suggested:
"A thought that was raised by a fellow Jacob breeder in MD last week: 'We
must do a better job of educating breeders on some basic color, piebald and
horn genes or we will find the Jacob breed unable to consistently reproduce
itself.  We can't just change the standard to accommodate what is in
everybody's flock.'"
I do not think that there should be no exceptions, only that the exceptions
should not become the rule.

Many of the traits that we are seeing crop up are the products of recessive
genes. Lilac, sex linked hornless (not polled) etc. can easily stay
submerged for long periods in the genome. We only have to look at the red
gene in Holsteins to see a case history of a recessive gene that becomes
legitimate after an extended period of time. The acceptance of these "off"
genetics eventually has much  to do with economics and personnel preference
and weighted opinion.

Neal Grose


----- Original Message -----
From: "Betty Berlenbach" <lambfarm at sover.net>
To: "Neal and Louise Grose" <nlgrose at yadtel.net>
Cc: <jacob-list at jacobsheep.com>
Sent: Wednesday, May 07, 2003 8:38 AM