[Jacob-list] Lilac (eeeeeeeeee) / Chocolate (bbbbbbbbbbb)??

[ranchrat at telusplanet.net]

Heel low:

Fred Horak <Jacobflock at aol.com> wrote:

> The Dominant Black is caused by an allele (form of a gene) at the EXTENSION 
> locus.  The Extension locus (always a capital E) controls fiber color and 
> skin color. (Yes, there is an argument to be made as to whether the extension 
> locus really exists.  

Optigen (http://www.optigen.com/) and Healthgene (http://www.healthgene.com/) 
both offer DNA color tests for the mutations “e” and “b” and I had such a color 
test done on my ACDog HyBlade.  Am I incorrect therefore to assume that if 
there is a little “e” as the documents I received stated he had, that there HAS 
to be an extension locus (as you stated above, always a capital E)?  Please 
further explain why anyone would be able to argue that the extension locus did 
not exist
what the heck did they test for then?

Geneticist Sue Ann Bowlings seems to have some trouble with the “dominant 
black” being in the extension series (E”d”) and I tend to agree with her there 
and if the beginnings of my theory that lilacs are from homozygous “e,” 
dominant black would have to be in the A series or some place else also to suit 
my fanciful guess
Yes, Neal, now I AM guessing what the lilac gene actually 
is
.sigh!  Why not
I guessed a long time ago that my dog was white&tan and that 
the color tan could be seen to be a red/sable phenotype.

Fred Horak <Jacobflock at aol.com> wrote:

> How many e sheep have you seen?)

Are some white sheep not homozygous “e?”  I own a homozygous “e” ACDog HyBlade 
who shows the affects of his double e by not being able to express the black 
pigmented hair his agouti series directs him to do.  If the lilac Jacobs did 
have homozygous “e” it would explain how they are able to retain the dominant 
black (A”s”) for their cross bred offspring to express in their phenotypes of 
being mostly black.

LILAC JACOB (A”s”A”s” ee) CROSSBRED to ANOTHER SHEEP BREED (XX EE) – sorry, I 
am too new to sheep color genetics to know what is the correct color gene for 
your modern white sheep breeds so I will use good ol’ X!

               LILAC JACOB – A”s”A”s” ee

              |   A”s” e   |   A”s” e    |
      _____________________|_____________|
 W S          |            |             |
 H H     X    |  A”s”X Ee  |   A”s”X Ee  |
 I E     E    |BLACK SHEEP | BLACK SHEEP |
 T E  _____________________|_____________|
 E P          |            |             |
  |      X    |  A”s”X Ee  |  A”s”X Ee   |
 XX      E    |BLACK SHEEP | BLACK SHEEP |
 EE   ___________________________________| 

Result:  100% A”s”X Ee {BLACK SHEEP}

- If the lilac Jacob was not homozygous dominant black (A”s”A”s”) and was a 
mixture, then would it not be safe to assume that some of its progeny could be 
black & white Jacob like because it was not homozygous for dominant black?? 
A”s”X ee x XXEE = 2 A”s”XEe (BLACK SHEEP) / 2 XXEe (JACOB LIKE SHEEP??)

We can just as easily throw in homozygous “b” in the above Punnett Square and 
voila, you could easily have a chocolate lilac
a rarer combination I presume 
for both recessive “e” and “b” to line up together, but certainly not 
impossible!  Recessives may lay in wait for generations prior to rearing up 
their interesting phenotypes when linked up to another recessive.

A”s”A”s” E- B- = Dominant Black Jacob Sheep
A”s”A”s” ee B- = Lilac Jacob Sheep
A”s”A”s” ee bb = Chocolate Lilac Jacob Sheep


Neal and Louise Grose <nlgrose at yadtel.net> wrote: 

> Our 'lilacs' are probably close in color to milk chocolate. These are 
> actually "red" or yellow undertones and not gray. Various people that 
> look at these sheep say that they see lavender undertones. I keep 
> looking over Fred's letter, and nothing fits perfectly to explain 
> lilac coloration.

Then please look at my prior post in regards to the E series and go to the link 
for Sue Ann Bowlings:

http://bowlingsite.mcf.com/Genetics/ColorGen.html#E
 “E, the extension series. This series is probably the least satisfactory of 
those generally assumed to exist in the dog. In most mammals, the E series 
includes Ed (dominant black), E (normal extension) and e (recessive red or 
yellow, and sometimes some intermediate alleles called Japanese brindles. In 
dogs, this is clearly not the case; breeding experiments have conclusively 
proven that dominant black and recessive red are not in the same series. This 
has led to dominant black being thrust into the A series, which as already 
mentioned conflicts with results in other mammals.
“In this summary, I will give the genes as postulated by Little, followed by a 
brief discussion of other possible explanations and a suggestion for matings 
that might clarify the situation. Note that the question is not in whether the 
genes occur, but whether they are in fact alleles in the same gene series. With 
regard to e and E, recent sequencing of the e and E genes in dogs show definite 
homology with those in other species.”
If Jacob Sheep had the e mutation (just as I will assume some sheep do in 
answer to Fred’s question, “how many e sheep have you seen?” unless he corrects 
me otherwise!!)  and the recessive “e” was the allele responsible for the 
lilacs, which you state above ("red" or yellow undertones and not gray) then 
lilac Jacob sheep are just like my Australian Cattle Dog HyBlade, the rare red 
from blues that set the ACD community on its ears!  The homozygous e disallows 
the black pigment from forming in his coat
minus black, the blue (mix of black 
& white hairs = blue) is just white, black (nixed by “ee”) is not present, and 
tan (the sable is left alone to be expressed and make one think he is a “red” 
ACD) is expressed tan and all this ends up equaling a phenotype red ACD.  

[Blue (white+black) + Black + Tan] – minus Black = white + tan = my red ACD

Why can’t homozygous “e” strip the black pigment from the Jacob’s dark body 
spotting and be expressed as the lilac coloration?  This would explain the red 
or yellow undertones of the “lilac” Jacob, would it not?  Then if a lilac Jacob 
is crossed to another breed that lacks the “e,” then the dominant black would 
again be allowed to be expressed.  Dominant black is not so dominant when faced 
with the power of those recessive little “e’s.”  Maybe Fred is correct in his 
question in regards to how many “e” sheep are there.  Maybe none
maybe just the 
Jacob who not only has dominant black, but also recessive “e.”  Watchya think??

I will approach HealthGene, Dr. M (forgive me, I cannot even attempt to spell 
his name correctly) and ask him if he is capable of testing for the e mutation 
in sheep.  As far as I recall, his color tests appear to be for horses and 
canines, but maybe he is capable of testing for the “e” mutation in sheep.  For 
$100, I may have a cheek swab/whole blood DNA sample tested on my lilac Jacobs 
(maybe Haley, maybe Melody or chocolate Jenny
even Mia/Nota/Nicto/Nascor who 
are all lilac factors
but let us not get carried away here) validated for the 
presence of the recessive e.

Heck, HealthGene is also able in the above test to test for the “b” mutation 
also
so what if chocolate lilac sheep are just homozygous e & b
that would 
explain the lack of blackish pigment (our dominant black Jacobs) and the more 
prominent brown coloration.  

For those concerned about the fact that the head and extremity markings being 
much darker on the Jacob lilacs (I have seen both lilacs and chocolate lilacs 
who look to have normally colored dominant black extremities), Bowlings also 
explains this phenomenon in the S series literature.

http://bowlingsite.mcf.com/Genetics/ColorGen.html#S

“It is not clear to what extent the S series affects head pigment. Color-headed 
white shelties, for instance (swsw), can have completely colored heads - not 
even a forehead star or white nose. On the other hand, relatively 
conservatively marked dogs can appear with half white or all white heads. There 
is probably at least one other gene series that affects head markings. It is at 
least possible that the plus and minus modifiers affect head and body markings 
simultaneously.”

As with all genetic study, we have to keep in mind that a whole bunch of stuff 
is going on at the same time
we are not allowed to have tunnel vision and focus 
upon only one area as all different genes make up the being as a whole.  Head 
coloration as I have mentioned prior may be inherited separately than body 
coloration, thereby explaining the rare red headed blue ACDogs and the blue 
headed red ACDogs.

Fred Horak <Jacobflock at aol.com> wrote:

>  A final note on color and conclusions.  The true color of a sheep may not be 
> accurate because we are limited in our description of color or, assume type, 
> breed, or offspring described by onesies and twosies is conclusive. Until one 
> gets ten progeny from known breedings, and results verified, it is helpful 
> information but not conclusive.  This is not to discourage cross breed tests 
> for color or other traits; but to carefully measure the result and temper 
> conclusions. 
 
I do agree that if one really wanted to prove Jacobness beyond a reasonable 
doubt (or at least within acceptable parameters
), that repeat breedings of ram 
to ewe that produced a total of at least ten progeny to judge their pureness 
would be the most scientific way to reach a plausible conclusion.  But in 
exchange for that certainty on those two animals (depending the measures you 
were using to judge Jacobness too), you are narrowing up the potential genetic 
diversity that geneticists like Willis warn us against (he suggests one NEVER 
repeat a matching if your objectives are keeping a gene pool diverse).  
Obviously, from my understanding of what Fred writes, he also expresses the 
costs we pay for achieving more plausible results to our questions.

Some do like repeating breedings over and over again
especially if the progeny 
are wonderful combinations of genetics that just meddled beautifully.  As 
pointed out to me, this does not do the Jacob breed any favours by being 
stunted generationally.  Some say this is a “closed flock” but even closed 
flocks require new genetics to stay healthy and move the breed forward.  There 
are risks for the rewards I suppose.

Doggone, 

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