[Jacob-list] Lilac/purity

[ranchrat at telusplanet.net]

Heel low Neal & list:

Neal Grose wrote:
 
> I thought that I should write back and clear up some of my thinking and
> statements. According to Mary Ellen, I have mostly "chocolate lilacs"
> except for one aged "grey lilac" that is sired by a ram of western
> stock. Dr. Sponenberg said once that "lilac is basically whatever isn't
> black". There may well be several lilac genes. 

Potentially:  D (blue dilute), G (graying), E (extension), B (brown), R 
(roaning)?

> What works for one may not hold for the others. I have excerpted Tara's 
> letter here.
> 
> > > This is going to be a little uncomfortable to say, but "lilac"
> > > expression is "proof" that the animal is "purebred Jacob".
> >
> > Cool!  I can only say that your "uncomfortableness" really does help =
> > put MY mind at ease.  :-/
> >
> > Yet another PLUS I figure for the lilacs if this color helps to prove =
> > a measure of pureness.
> 
> Let's not get crazy here.

Ahhhhh...there is a fine line between sanity and insanity they say and I 
certainly enjoy weaving along the divider with my Jacobs butting back and 
forth ;-)

> "Purebred" is not the same as purity. You could make a case that all breeds 
> start as crossbred, and then are reselected for type. "Purebred"
> is relative, and has a arbitrary starting point. Purity is near impossible. 
> What I am saying is that lilac is intrinsic to the Jacob genome.

Better than no clues!  One could say that practically ALL life is a divergence 
from the pureness of the first cell that originated life itself.  You have 
already stated:  

"I have never seen a crossbred lilac sheep. In my experience, the sheep has to 
be at least 3/4 Jacob in order for lilac to be expressed at all.
  "This is going to be a little uncomfortable to say, but "lilac" expression 
is "proof" that the animal is "purebred Jacob"."

The dog world is way more concerned about purity than the sheep world has 
been.  Having DNA profiled and parentage tested canine progeny, I know to what 
lengths one may go to try validate a pedigree.  Some will be satisifed with the 
first generation tested to prove dam & sire...others would not be satisfied 
with a 30 generation line of DNA parentage testing.  The concept that lilac 
phenos are at least 3/4 Jacob is a good place to start when one is looking at 
say purchasing a Jacob at the auction mart/from unknown heritage.  Further 
conformation like progeny testing would then give one even more "insurance" or 
satisfaction that one had a Jacob of some degree.

> As a single gene, it can certainly get shuffled around to somewhere else. I 
> do not see lilac cropping up from other breeds and know of no other breed 
> where it is found. One theory is that lilac is a form of moorit. Having seen 
> both now, I do not think so. If anything, normal Jacob "black" is a super 
> dark brown (moorit?) and to my eyes, lilac is off tone from that.

OK, 'splain "moorit" for those of us not blessed with one of Betty's rams!  Is 
this a color shade in sheep or ?  Expression of phaeomelanin then?  There 
verges a point where one cannot tell if it is eumelanin or phaeomelanin being 
expressed by the hair follicle...believe me!  I make this point because we had 
two Biology classes discuss this phenomenon at great length (even under 400X 
magnification) trying to determine if my ACDog HyBlade was expressing black on 
the tips of his body hairs!  I also got to spend a most pleasant Saturday 
afternoon in a certain Jacob barn staring my eye balls out trying to see if a 
lamb was lilac or black...my eyes still hurt!  I find the fact that fine black 
Jacob fiber sunbleaches to a pretty brown to be complicating the phenotype 
parameters of lilac and black!  I see I am not alone if you say that 
Jacob "black" is super dark brown.

> > > When we cross our lilac Jacob sheep to homozygous white longwool
> > > sheep, we get piebald black and white lambs. I have done enough test 
> > > crossing that I am reasonably sure that the black is the dominant Jacob 
> > > black.
> 
> > To keep this all straight in my mind, I figure so far that lilac is
> > basically a simple recessive (l for lilac gene, B for dominant BLACK; 
> > homozygous "l" (ll) gives pheno & geno lilac, "Bl" gives pheno black and 
> > geno lilac factor and "BB" is dominant black pheno/geno).
> 
> OK, my explanation is going to seem a little goofy. What we have seen in
> our flock refutes what Tara says and what is commonly thought. By the good
> graces of our friend Betty who lent us a moorit Shetland ram, we will
> soon have a few moorit Shetland X lilac Jacob lambs. I predict that they will 
> be black and white, just like the lilac X white longwools.

Please validate if your prediction is correct when they are born!
 
>  Recessive genes are only expressed in absence of the dominant gene. The
> lilac is not following this model, instead we are seeing black expressed
> in absence of two lilacs.

Goofy?  Brilliantly explained.  This easily nixes my concept that we ARE 
dealing with simple recessive/dominant relationships.  Thank you for clearing 
this up.  For a lilac to have its crossbred progeny revert to the dominant 
black of the Jacob in the absense of the homozygous lilac is an excellent 
example of why the lilac cannot be a simple recessive/dominant.  How can 
dominant black express itself in a cross bred lilac if it does not have it 
hiding in there to give.  We pretty much know that most sheep breeds do not 
have the dominant black, so for a cross bred lilac Jacob to have a black & 
white offspring, the dominant black had to have come from the lilac.

I have not had the luxury of having someone discuss why what I have been seeing 
in the Jacob to Jacob breedings said anything BUT recessive/dominant.  I may 
continue to expect what I am predicting as offspring in lilac and lilac factor 
breedings BUT in using this method, I would never have uncover what exactly is 
happening to make the lilacs lilac.  The geneticists like Malcolm B. Willis 
(Genetics of the Dog) and Sue Ann Bowlings 
(http://bowlingsite.mcf.com/Genetics/Genetics.html) all make references to test 
breedings (studies done with cross breeding of the target breed) to really 
discover the true genetics involved.  You have done the cross breeding and will 
discover far more genetically than those of us who just plod along breeding 
Jacob to Jacob.  I look forward to hearing that the Shetland (moorit) x Jacob 
(lilac) progeny is as you predict; black & white.

> My thinking is this:
> Instead of heterozygous black/lilac shown as (B,l) with these two genes
> at the same locus, these may be at two different loci with (L) as a
> modifier for (B). "Lilac" is recessive to "normal non-lilac", not
> "dominant black". If (B) is dominant Jacob black, (L) is dominant
> "normal" and (l)is recessive lilac; then genotypes may be expressed as:
> 
> B,B + L,x =3D black, homozygous black
> B,x + L,x =3D black, unknown genotype
> B,x + L,l =3D  heterozygous lilac (lilac carrier)
> B,x + l,l =3D lilac expression
> 
> [This omits recessive black, dominate and recessive white, and 
> piebald(s). The whole thing could quickly get too complicated to muddle 
> through...]

Not to confuse the above use of the letter "B," but "normal non-lilac" sounds 
similar to the B series in the fact that B- (BB / Bb) allows for the full 
expression of black pigment.  For my ACDogs, their two recognized coat colors 
(red/blue) are at the A series (agouti locus).  The A locus is said by some 
(geneticist Little) to be where the dominant black allele resides (A"s").  
Homozygous "b" (bb) is brown/chocolate (phaeomelanin) and modifies the A series 
in that I have seen "bb" ACDogs who are chocolate BLUE (beautiful brown like a 
Labrador Retriever along with ochre tan points) or chocolate RED (brown also, 
but could be mistaken for a sable/red quite easily other than their "pink" toe 
nails tattle on them) depending upon what is expressed in the A locus (a"t" 
blue/black&tan or a"y" sable/red).  Jacobs could quite conceivably be dominant 
black A"s"- BB for black&white and A"s"- bb for chocolate lilacs??
 
> > "...Where the fading lilacs come from (maybe incomplete dominance or
> > modification from another series or +/- factors, or roaning?), or..."
> 
> I am pretty confident that the fading/premature graying in lilacs is the
> standard premature gray that we see in the black and whites. People have
> not culled lilacs as readily as the black and whites. We have quite a
> few lilacs, and we do not commonly see premature graying.

Forgive me for not knowing yet that both black and lilac Jacobs will gray up--
have not had Jacobs long enough to notice this yet ;-)  I thought I read a 
discussion by some that they had lilacs who did not fade and retained their 
grey intensity.  I did not know this was a similar factor in the black & whites 
also.  From what you are saying, it seems that some Jacobs "prematurely grey" 
(black or lilacs).  I have heard that "freckling" or the tiny dotty dots 
increase with age for some Jacobs (R series/roaning?), but there seems yet 
another phenonmenon to Jacobs, the age fading of the darker areas in their 
fleeces...I shall watch for this in my own flock with increased interest.  I 
figure the non-age affected spotting/ticking is from the T series also 
responsible for the body and breed markings/spotting.  The S series gives the 
Jacobs their white markings (piebald s"p" and extreme piebald s"w").

The D series (dilution) or the G series (graying) could all play factors in 
both fading and the lilac coloration as these are said to fade black to steel 
blue (some of our grey Jacob lilacs' coloration?).

We had a great speaker at one of our sheep meets who did a spiel about wool.  
Not many know that wool is the only fiber-manmade or otherwise-that actually 
generates heat when it gets wet--no wonder it's warm to wear!  This speaker 
told us that sheep's fiber actually thickens with age (explains why a sheep's 
first fiber is considered its very best).  Could the slight increase in the 
follicle shaft over time be attributed to the "fading" we see in the dark 
areas?  If the pigment amount stayed the same but had to be "stretched" out 
over a larger area over time, it would "physically" explain why color intensity 
seemed to fade.  I presume the age fading you mention is along the entire 
follicle?  Does only the dark areas fade or does the intensity of the white 
also wane?
 
So why could the lilac not be from the affects of homozygous "e?"  The E 
(extension) series allows for the full expression of agouti with "E-" but 
homozyous "e" modifies (epistats is the term??) the A series.  Some even say 
that dominant black is in the E series (E"d").  The expression of "black" is 
supressed by "ee."  Not fully because my dog HyBlade (DNA color tested BB ee) 
has those black tipped hairs, but "ee" strips the hair coat of black (in varing 
degrees depending upon the individual--HyBlade appears red/sable, but is 
actually an homozygous agouti blue/black&tan who is not allowed to express 
black therefore is just white and tan). I suggest "ee" because I also see the 
dimming or diluting of pigment intensity in the lilacs as I see in my dog who 
has lighter nose leather, irises that have faded from pitch black to 
brown...some Lilac Jacobs have lighter horn coloration, irises are "different 
(lighter amber with a grey overtone).  If the Jacob dominant black is actually 
a dark brown (Bowlings suggests that there are times where the pigments 
overlap, especially in the deep browns and black), the modification of that 
dominant black by "ee" would supress the expression of black and leave 
the "brown" to be expressed therefore explaining the "chocolate" lilac at 
least!  The grey of the lighter lilacs still confounds me and may be the 
unraveling of thinking the E series has any part in the lilac genetic 
explanation...unless ALL Jacob sheep are actually just grey sheep who are 
subject to white spotting (S series), namely the piebald.

> > "...Speaking about testing, has anyone DNA tested the Jacob to prove
> > that it is NOT a cross developed historically from a goat and a sheep as 
> > some rumour to have occurred?  This theory has some merit in the phenotype 
> > of the Jacob, that there have been goat/sheep crosses that have lived and 
> > shepherds of old kept both together. .."
> 
> As I understand it, sheep and goats do not normally produce viable
> offspring. If they did produce live offspring, they probably would not
> reproduce, much like mules do not produce offspring. 

Strange country maybe up here, but we have had mules that are fertile and 
produced progeny...whether these went on to replicate, I never bothered to 
ask.  I am told that hinnies (horse sire/donkey dam) have a much higher rate of 
conceiving than mules (donkey sire/horse dam). 

> That said, the more primitive sheep crossed on more primitive goats can 
> sometimes produce viable offspring. There are some reliable reports of Angora 
> goats and Jacob sheep producing live offspring.

Wow, that would be some interesting fleece AND horns!  We have a sheep farmer 
here that uses dairy goats to raise her bummer lambs...it is quite neat to see 
lambs mothered up with goats.  She gets alot of thru traffic with her wool shop 
and there are probably many who do not even notice that there are baas nursing 
off the maas!  ;-)

> I would go with the story that Jacob sheep are descended from Mouflon sheep, 
> since (if I remember correctly) most sheep breeds ARE descended from them. 
> Sheep and goats do have a common ancestor.

So nobody yet has tested Jacob DNA compared to goats.  I would be interested if 
there was a DNA test yet available to do such a comparison.  I know when I 
worked for the Min of Environment Conservation Office, they were in the process 
of finalizing DNA testing on two sub-species of Elk...one for the farmed 
animals, the other to identify the native species--all in an effort to 
prosecute poachers.  Last I knew, there was finally a test to determine if a 
Dingo was actually a Dingo.  For conservationalists, this was a most important 
undertaking because the only way prior was to boil their skull and take 
measurements off it (larger than a domestic dogs).  Sorta a backwards kinda way 
to conservation.  You only knew the animal was a Dingo after it was dead  :-p  

One day there just might be a cheek swab test for Jacobs to verify (OK Neal, 
now I'm thinking I should be scared to say the word "pure!") "Jacobness."  I 
believe right now we are still unable to take DNA from a Cotswold against a 
Suffolk and know which is which.  Says something good about our ability to see 
phenotype!  From what I understand, Jacob pureness (gulp, there I said it...) 
is still at the "walks like a duck..." stage and only through looking at what 
they produce do we have any control over what we *think* we are conserving in a 
full blooded state.

Whether the economics of parentage/pedigree testing will ever be justified, who 
knows (parentage testing is $100 on canines, $150 for llamas--so maybe the 
Jacob herd sires would justify such a cost).  The dog world is going through 
the throws of parentage testing, so is the llama world too (llama studs have to 
be DNA typed prior to their progeny getting Canadian registration-dams are 
still optional--the new show type of llama called a "sury" is said to be a 
cross between the Alpaca and the Llama!).  I doubt any would ever want 
manditory Jacob testing but in a conservation kinda light, DNA typing would 
certainly put more integrity into a breeding program.  Understanding of course, 
the Jacobs would only be as "pure" as the specimens one chose to begin the 
testing from...outside genetics would probably skew everything!  One of the 
Achille's heels in the ACDog world is that their historical roots began with a 
cross of a Dingo & a Collie...so who at that time was keeping the 
pedigrees/pureness in the Dingoes...so much for blue blooded integral 
pedigrees!  VBG

I would like to see us have the option to DNA parentage test Jacobs if we so 
desired.  Somehow though, I doubt this will happen any time too soon.

Doggone,

Tara
--
     ____(\                Tara Lee Higgins                  /)____
    (_____~>        Rat Ranch - An ACD is for LIFE          <~_____)
   ( ``  ``          ranchrat at telusplanet.net                ``  `` )
    \                       Alberta Canada                         /
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