Conference misery::feline_v1

    I have a genetic question for you.  I have a sealpoint Birman female
    that (I think) carries the bluepoint gene.
    
    questions:
    
    Dam was a sealpoint, Sire was a bluepoint, sealpoint is dominant
    so therefore my kitten is seal carrying blue?  Dam also carried
    blue gene so there were blue kittens in the litter.
    
    I was told by another breeder that even if I did mate my female
    to a seal only male I could still get a blue in the litter.  I don't
    understand that because it was my understanding that in order to
    be blue a kitten had to recieve the blue gene from both parents.
    
    What do you know about this?
    
    JoAnn

    I don't know anything about sealpoint vs. bluepoint, so I will assume
    that your description of seal being dominant over blue is correct.
    
    In that case, a bluepoint cat would HAVE to have 2 bluepoint genes,
    one from each parent.  A single sealpoint gene, from EITHER parent,
    would be dominant over the (recessive) bluepoint and thus cause
    the cat to appear sealpoint.
    
    Thus, a sealpoint cat COULD have 2 sealpoint alleles (one of the
    "pair" of genes, one from each parent).  But it also COULD have
    one sealpoint and one bluepoint.
    
    So...if two sealpoints mate, there is a possibility of bluepoint
    offspring IF each sealpoint is carrying a recessive bluepoint allele.
    If both have 2 sealpoint alleles, then there would be no possibility
    of a bluepoint offspring.  But if both types of sealpoints look
    alike, then unless you have sufficient information from many
    generations back, you might indeed not be certain about the color
    of the offspring.
    
    As I said, I'm not familiar with the specifics of seal/bluepoints.
    If the combination (one of each type of allele) has an intermediate
    appearance, then the above discussion is not correct.
    
    Hope this makes some sense -- let me know if it's too concise.
    
    	Penelope_who_used_to_teach_genetics

    Penelope,
    
    I understand Mendel's laws of genetics and that is why I am confused
    by the info I received from this other breeder.
    
    the parentage of my female is:
    
                Sb x bb
     
    the way I understand it that would have netted out of four kittens
    
            Sb  Sb bb bb
    
    with two seal kittens and two blue kittens.  Is this correct so
    far?  My kitten is Sb, so in the instance given in my previous reply,
    if I mated my Sb kitten to a SS cat I would get the following
    combinations   SS SS bS bS with all kittens appearing to be seal.
    Is this correct?  As I understand it there is no way to get a blue
    kitten in this instance.  What bearing do the past generations play
    (if we already know the alleles of both parents) in this generation
    of kittens?
    
    JoAnn
    

    Since I also used to teach genetics -
    
    What Penelope meant was that you can't tell if a cat is SS or Sb
    just by looking at it. It could be carrying the recessive even if
    it had not shown up for many generations. If the male's genotype
    is indeed SS and the sealpoint/blue characteristic is a simple
    dominant/recessive situation then you would indeed get only 
    Seal point kittens.

    Hi JoAnn,
    
    (This is REALLY difficult to do not_in_person and using a typewriter
    rather than diagrams, but here goes... You've got the right ideas
    in general.)
    
    Your kitten's parents are sealpoint and bluepoint:  that could be
    either
    
    		Sb x bb 	OR 		SS x bb
    
    Let's assume the left-hand model, for the moment, although we may
    not know for certain.  There are two "possible kitten types" from
    such a mating, and they are determined by all possible pairs of
    alleles such that one comes from Sire and one from Dam.  In this
    case, because one parent has only "bb" there are only two kitten
    types possible:
    		    Sb   (S from left parent, b from right)
    		    bb   (b from left parent, b from right)
    
    So, in this case, EITHER WAY, the kitten will carry the recessive
    bluepoint allele, either as a bb bluepoint or as a "heterozygous"
    (one of each allele type, an "S" and a "b") Sb sealpoint (as
    opposed to a "homozygous" SS sealpoint).
    
    Thus, still using the top left-hand model, your kitten would have
    a "b" allele, and IF it combined with another "b" from the mate,
    that particular offspring would be "bb" bluepoint.  That "b" from
    a mate could come EITHER from a "bb" bluepoint OR from an "Sb"
    sealpoint.  But if your Sb kitten mates with an "SS" sealpoint,
    there would be no way that any of their offspring could have a
    "bb" combination.  (One allele comes randomly from the sire, and
    one comes randomly from the dam -- if one of those parents has ONLY
    SS alleles, then seal will be the appearance, regardless of whether
    the other allele is S or b.) 
    
    If your kittens parents were actually SS and bb, you'd still have
    an Sb kitten, and nothing else could happen in litters from those
    two parents.
    
    The point here is that you apparently have a heterozygous (Sb) seal
    rather than a homozygous (SS) seal.  Therefore, if you mate your
    kitten with another sealpoint, that other cat MIGHT also have a
    recessive blue allele -- depends upon whether that other sealpoint
    is SS or Sb (that's why knowledge of the past generations of the
    other cat MIGHT provide some indication).
    
    If your Sb cat mates with an SS, then the offspring must be sealpoint
    (either Sb or SS).  But if your Sb mates with another Sb, then all
    4 combinations are possible:
    
    			Sb x Sb     could generate:
    			-------
    			S    S      seal (homozygous)
    			S     b     seal (heterozygous)
    			 b   S      seal ( " )
    			 b    b     blue (homozygous)
    
    In such a mating, each of the four genetic types has a 1/4 probability
    of occurring (with a 3:1 ratio of seal:blue appearance), but (ignore
    twinning) you could conceivably (pun intended!) get all blues or
    no blues, etc. in any specific litter.  In the long run, over many
    such litters, you'd see the 1/4 probabilities genetically, and the
    3:1 appearance ratio. 
    
    Does this help or make matters worse?
    
    	:^)  

    Thank you all very much for answering my question.  As I had thought,
    the other breeder was mistaken and I was correct.  My female kitten
    is heterozygous as was her dam.  The sire was a blue.  I order to
    get blue kittens I have to mate her to a homozygous blue or a
    heterozygous seal.
    
    JoAnn

    just my cent's worth.
    
    The original question asked if you bred to a "SEAL ONLY" male, you'd
    get all seal kittens. True.
    
    But the catch is telling a seal only male.  As was pointed out,
    past generations can give that information. (I include colors of
    littermates on my pedigrees, for that reason).
    
    If you breed to a blue, you'll get the 50-50 split, on the average.
    
    For you genetics buffs, the genotype for a seal is
    
    	aaB-c(s)c(s)D-
    
    and blues are
    	
    	aaB-c(s)c(s)dd
    
    The c(s) is a recessive of the albino alleles series.
    For longhairs add the ll combo and for Birmans add the white spotting
    factor.
    
    Dave

    JoAnn:
    
    My female sealpoint Siamese is half-bluepoint.  My male is all
    sealpoint.  We did get chocolate-point kittens from their litters,
    but no blues.  In order to receive bluepoints, we would have had
    to mate Mutu to a bluepoint male.  So, you're right...Blue is recessive
    to Seal (brown), "ergo" to get bluepoint kittens, your Birman
    half-bluepoint would have to mate with a male all bluepoint.  Make
    sense?
    
    J.

    Or a sealpoint carrying the recessive blue gene.  Dave, can you
    give me some specifics on chocolates and lilacs?  I am not sure
    how you would actually get those colors.
    
    JoAnn

    THANKS DAVE - FOR THE INFORMATION ON THE DEAFNESS IN CAT GENETICS.
    IS THERE ANY "PERCENT" CHANCE OF MY FEMALE, DEAF CAT HAVING DEAF
    KITTENS OR WOULD MORE TESTS NEED TO BE PROVIDED?
    

Regarding blue point and seal point birmans, it is also possible to get a
blue point from a Dd x DD cross via a new mutation.  Rare, but it happens
(after all, that is how we got blue points in the first place).

--PSW

re:  how you get all the colors

	Caveat:  The following discussion is good for Siamese, 
	Tonkinese, and Burmese.  Some modifications would be 
	required for other breeds.

Once you know what the genetic description is, you just play around with 
the combinations.
						     s s
The genotype for a sealpoint Siamese is:	aaB_c c D_
						     s s
The genotype for a bluepoint Siamese is:	aaB_c c dd
						     s s
The genotype for a chocolatepoint Siamese is:	aabbc c D_
						     s s
The genotype for a lilacpoint Siamese is:	aabbc c dd

			      s s       b b
	For Burmese, replace c c  with c c .  The colors, in
	order, would be sable, blue, champagne, and platinum.
				s s       s b
	For Tonkinese, replace c c  with c c .  The colors, in
	order, would be natural, blue, champagne, and platinum.


Let's say we're trying to get lilacpoint Siamese, and we've got blues and 
chocolates to start from.  (Let's further assume the blues aren't carrying 
chocolate, and the chocolates aren't carrying blue.)
		     s s            s s
The parents are aaBBc c dd and aabbc c DD.  The first generation kittens 
	       s s
are *all* aaBbc c Dd.  If you look back at the chart, you'll see that these
are all *sealpoints*, but are carrying both blue and chocolate.  If we then
breed two of these first-generation cats together, we get rainbow litters.
Over many litters, the distribution is: 

	1/16 sealpoints carrying neither, 
	1/4  sealpoints carrying blue and chocolate, 
	1/8  sealpoints carrying blue,
	1/8  sealpoints carrying chocolate, 
	1/16 chocolatepoints carrying nothing, 
	1/8  chocolatepoints carrying blue, 
	1/16 bluepoints carrying nothing, 
	1/8  bluepoints carrying chocolate, and 
	1/16 lilacpoints. 

Pick different starting points, and you can figure out what is and is not 
possible to get, and in which proportions.

The only(!) problem is determining whether an individual cat is carrying 
the masked traits.  That's when you look at the results of other breedings, 
(if any), what's in the pedigree, and what other related cats are.

Ray

For "regular" cats (Domestic Shorthair) how do the various white genes work?
What are the "white masking" and "white spotting" genes?

I know about the sex-linked "orange" and "grey/black" genes on domestic
shorthairs and how they work but always wondered about white.

Also, do Siamese have an equivalent to the sex-linked "orange" gene?

If so, is it possible to get an orange Siamese-looking cat by crossbreeding a
Siamese and orange D.S. and breed the offspring with Siamese while selecting
for orange?  Not that I'd want to do that...  Sorry if this offends the morals
of some breeders. :-)

-Mike

re: 422.13

>Also, do Siamese have an equivalent to the sex-linked "orange" gene?

I'll give this one a shot -- maybe someone else can cover the different 
kinds of "white".

The answer to your question as stated, is by definition "no".  However, 
there's a breed called Colorpoint Shorthair which is essentially Siamese
with a lot of the other stuff thrown in.  Their genotypes follow below. 
(The notation expresses "sex-linked" using "()".  "O(O)" means the male is
"O" and the female is "OO".  "Oo" (or tortoise shell) is only possible
(normally) for females.  The allele "o" denotes normal pigmentation, "O"
denotes all pigment turned to yellow/orange.) 

				   s s
red point			aac c D_O(O)
				   s s
cream point			aac c ddO(O)
				     s s
seal tabby point		A_B_c c D_
				     s s
blue tabby point		A_B_c c dd
				     s s
chocolate tabby point		A_bbc c D_
				     s s
lilac tabby point		A_bbc c dd
				   s s
red tabby point			A_c c D_O(O)


				   s s
cream tabby point		A_c c ddO(O)
				     s s
seal tortie point		aaB_c c D_Oo
				     s s
blue tortie point		aaB_c c ddOo
				     s s
chocolate tortie point		aabbc c D_Oo
				     s s
lilac tortie point		aabbc c ddOo
				     s s
seal tabby tortie point		A_B_c c D_Oo
				     s s
blue tabby tortie point		A_B_c c ddOo
				     s s
chocolate tabby tortie point	A_bbc c D_Oo
				     s s
lilac tabby tortie point	A_bbc c ddOo


As far a crossing a Siamese with an American shorthair to get colorpoints,
well, you'd theoretically be able to do this, but the phenotypes are so
wildly different, it would take you a long time to get the type back.

Ray

    The white color of cats is caused by two different gene sources.
    
    The all-white cat is usually caused by the gene W, a dominant white
    masking gene.  Behind this gene may lie a cat of any color.
    Interestingly enough, while the W is considered dominant, it does
    seem to vary in masking, resulting in occassional breaks of color,
    which normally disappears when the cat grows up.
    
    Eye color associated with white cats is usually blue, copper or
    odd-eyed (one of each).  As noted, the white cat is more likely
    to be deaf than other breeds. (as an aside to another note, deaf
    cats can make poor mothers, as they can't hear the cries of their
    kittens. The chance of the kittens being deaf is fairly high, as
    the W gene and the S (white spotting factor) are both dominant.)
    Deafness is more often associated with the blue eye, but can be
    in conjunction with either.
    
    The white spotting factor, S, is usually called the piebald factor.
    This gene is an incomplete dominant, so a homozygote S usually has
    more white than a hetrozygote, but not always. There are modifying
    genes and also non-genetic variations (including, some report, the
    mothers body temperature).  There may also be a recessive white spotting
    gene, some believe that the Birman caries this gene, which accounts
    for the minimal spotting.  Cat colors start along the spine and
    migrate around the cat as it develops. The white spotting factor
    inhibits this miagration, but in various spots.  That's why the
    patterns are different all the time, and why the white is on the
    belly and feet, not on the back with colors on the feet.
    				   a
    There is also a albino white, c  , which can cause white albinos
    with both blue and pink eyes.
    
    Dave

    Is the blue eye color only associated with siamese, hymalaian (sp?)
    and white cats? or is it possible to get an all black cat with blue
    eyes that does not have siamese background or that is not deaf?
    
    As an aside:  I had 2 brothers (both
    black) from the same litter, the mother and father were both black;
    the mother was 1/2 or more siamese (short haired) and had triple paws.
    The father must have been long or med. haired because one kitten
    had long hair and double paws, and the other had short hair, normal
    paws, but the siamese personality and meow. (both had yellow eyes)
    A cat I have now is black, med-haired w/green eyes.  Her mother
    was all white (short haired w/green eyes) and the father was a
    long-haired black with yellow or green eyes.  It's interesting to
    see the random combination of kittens produced by such parents.
    
     I haven't ever seen any black cats with blue eyes advertised, and
     wondered what you would have to cross to produce it.  I assume
    that black coat color is dominant, and that my cat must by carrying
    a white recessive gene (ie. Cc, BB - C for color, B for eye color) If
    she were bred to a white cat with blue eyes (cc, bb) then the outcome
    would be black or white kittens carrying the recessive blue-eye
    gene.  If the black kittens from the litter were mated, then there
    is a potential of getting a blue-eyed black kitten, right?
    
    I didn't bother with the coat length or deafness, but I assumed
    the white, blue-eyed cat was not deaf.  I'd appreciate any corrections
    or other info.  

    How about some discussion on the breeding of manx and scottish fold
    cats and the gene combinations which produce the taillessness and
    folded ears.  Note 437 has some questions on manx cats and I have
    only limited knowledge about the breeding of them.  I do know that
    there is a lethal gene combination formed when to tailless cats
    are mated but I don't know what causes it.  Any one care to try
    their hand at answering these questions?
    
    JoAnn

    Also in Manx topic 437.
    
        There are a lot of interesting legends about manx cats, and how
    they lost their tails (Irish invaders stole the tails for helmet
    plumes?). But nontheless, the lack of tail is blamed on a dominant
    genetic mutation that happened a long time ago, especially when
    you consider that there was a Manx club in Great Britian in 1901.
    King Edward VII owned several.
    
    Breeding and genetics.  The M gene is lethal in homozygote, causing
    death in the womb at an early age. This is approximately 25% of
    kittens in a Manx to Manx breeding. Heterozygote Manx (the tailless
    wonders) show a high percentage of still-births and kitten deaths
    than the norm.  They are also more apt to have other malformations,
    particularly of the spine, such as bone fusion of the lower spine,
    incomplete spinal development (nerves unprotected by bony material),
    and spina bifida.  
    
    Manx are split into 4 groups (the hetero nature means they can never
    breed "true")
    	rumpies - dimple where tail should be
    	rumpy-risers - small number of tail vertebrae forming a knot
    	stumpies(or stubbies) - definite tail stump, movable
    	longies - nearly a normal tail
    There are also normal tailed cats from a Manx breeding.
    
    Long haired Manx are called Cymrics (from Cymru, the Welsh name
    for Wales). It has been recognised is some fancies.
    
    Manx are sweet, affectionate, and infinitely lovable (aren't they
    all?).  But it is one of the breeds I would NEVER breed (the others
    are Sphynx, Burmese, and Scottish Fold).
    
    Dave
    

    Re .18
    
    The New Zealand Cat Fancy (I can't speak for any others!) will in
    fact not allow kittens from the mating of two Manxes to be registered,
    as the chance of the lethal homozygous occurring is considered
    irresponsible (my words, not theirs).
    
    Dave, please explain yourself! Why not Burmese??!! I can understand
    the others, from a health point of view, but Burmese are tough as
    old boots, and have one of the longest average life expectancies
    of any breed, as well as being incredibly affectionate. Please
    elucidate.
    
    SLP (owned by an Abyssinian and a Burmese (an offended one))

    Burmese...
    
    If you have an old style Burmese, or a non-American one, I'll retract
    the remark.  But if you have kept up with the current SOA in burmese,
    then it is highly probable that you have a genetic problem in your
    cats.
    
    Please forgive me, I'm trying to do this off my head, rather than
    via my genetic class notes.
    
    Burmese breeders decided to go to a round head, flat nose.  One
    male cat became very successful in the show ring (Cat will remain
    unnamed).  This cat can be found in most recent american bred burmese
    pedigrees.
    
    Burmese began have birth problems, ranging from cleft palates to
    incomplete skull formation, and other related problems. A VERY high
    death rate appeared in kittens.  This issue became so bad that the
    burmese breeders went to the various cat genetists (like Solvig
    Pfleuger, and "what's his name in England"). The issue was serious
    enough that "what's his name" even flew (for the first time) to
    New York for a round table.
    
    Burmese breeders know the problem and are trying to correct it.
    
    For more information, check the back issues of Daphne Negus' CAT
    WORLD (now part of the exhibitor's edition of CATS)
    
    I'll check my notes and add/subtract as necessary.
    
    Dave

re: .18, .19, .20

The Burmese in New Zealand are almost considered a different breed 
("Foreign Burmese") than the Burmese shown here in the States.

When we were considering getting into breeding cats, we originally wanted 
to go with Burmese, but decided not to because of the genetic health 
problems common with the extreme types that are winning these days.  Also, 
there's no way I want to be associated with litters containing kittens
trying to nurse, but not able to because they had no mouths. 

BEGIN_OPINION:
The Burmese breed here in the States is on the brink of disaster.  It's 
been demonstrated that the extreme head type and the genetic defects are
linked.  The only way they can recover is to ensure that the extreme types
lose in the show ring (by changing their standard, if necessary), and
aggressively cull those cats with genetic defects from their gene pool
before it's too late. 
END_OPINION:

Besides, I like the way the traditional and foreign Burm's look better than
the extreme types, anyway. 

Ray

    Me too.
    
    I almost started breeding burm's, but I (Sorry persian and related
    breeds) don't like cats that chase parked cars.  I found out that
    there was a genetic problem later, so went with the (then) easiest
    and healthiest cat to breed, the Maine Coon.
    
    But to show I'm not totally unaware of what is going on...
    
    In the last few years, a more extreme type of maine has begun winning,
    especially in TICA, where maines are definitely not a minority breed
    (one show had 75 maines entered).  One breeder began doing very
    well with her cats, so well that her cats won against all other
    types. They grew large earlier, and had pointier (?) heads. (The
    standard calls for a modified wedge, which is judges opinion. Of
    course, the standard also calls for a "moderate sized" cat).
    
    Everyone but for a few of us (me included), started breeding to
    her stud cat.  About a year or two later we had queens dying in
    labor, gigantism (abnormal rapid size growth, usually fatal around
    7 monthes of age), tail deformations, and "sunken chest syndrome"
    (chest fails to fill out as cat grows).  Obviously, something was
    wrong. This went on, increasingly worse, for a few years.
    
    TICA's staff genetist (TICA has two world renown genetists, the
    other being Don Hunter) traced back the problem to this lady's stud
    cat. But the damage was done.  Judges looked for the traits of this
    breeding and awarded those cats.  Most cats had that bloodline.
    
    Breeders are beginning to recover from this damage, culling all
    cats that show any traits (by altering if the cat survives).  I
    would possibly use a cat if the bloodline of this cattery wasn't
    too recent (say 5 generations?).  Fortunately, CFA tended to stay
    with the older, healthier style maines, but it is hard to show a
    minority breed in CFA, in spite of maines being the fastest growing
    showcat, and the fourth most popular breed. (Points to those who
    can name the top three).
    
    There are similar horror stories about most breeds.  It just seems
    than mankind can't leave well enough alone (look at dogs and horses
    as well).  It also seems that burmese breeders were a bit more stubborn
    about recognising and responding to the problem than most.
    
    These are my opinions.  While not flames, I do tend to get upset
    about cruelty to animals, no matter what form. (You should hear
    me expound on the LD50 test).
    
    Dave

    Dave and anyone else interested...
    
    The top 3 breeds are Persians, Himalayans, and Siamese.  I believe
    in that order.
    
    cin
    

    I would have guessed persians and siamese in that order but not
    himmies.  I would have included himmies under the persian breed,
    and picked abyssinian as number 3.
    
    This is based on no special knowledge, just a guess.
    
    Jo Ann

    Actually, the order is dependent on where you get your results from:
    
    CFA
    SPCA
    Cats Magazine
    other.
    
    Dave

    Well, if you group Himmy's with Persians, then I would have to agree
    that Aby's are probably 3rd.  
    
    Does this mean I don't get a prize???
    
    tee hee
    cin
    

    Since he hasn't told us the real answer...how do we know if you
    loose or not?  Tell you what, we will declare ourselves the winners
    and split the prize 50/50.
    
    jo

    cin,
    No I didn't mean that you were "loose".  What I meant to say was
    how do we know if you LOSE not loose.
    
    teehee
    jo

    Re note .20 and others...
    
    Thanks very much for your informative replies... I was SHOCKED to
    hear about the genetic defects. I knew American Burmese looked
    different from those in the rest of the world, but hadn't realised
    there was a genetic caveat that went with the different look. Burmese
    certainly have a name for being super-healthy (as well as very bright)
    in this part of the world.
    
    I guess that all you Americans know the reason behind the look-change
    in American Burmese? If not, and if anyone is interested, I'll dig
    out the saga.

Well, so you want results...

All-American scoring by show entries
	Persian		(down 8.96% from last year)
	Himalayan	(down 4.55%)
	Siamese/CP	(up .533%)
	Maine Coons	(up 20.7%)
	Abyssinians	(up 13.3)

As an aside... it seems that the 86-87 show year will be the last All 
American year

CFA order
	Persian/Himmies
	Siamese
	Abyssinians
	Maine Coons

SPCA order (I don't know where they got their info)
	Persians
	Abyssinians
	siamese
	Maines

    I am interested...please do dig it out.
    Jo

    I'ld be interested in the saga too....please post it.  Might be
    a good idea to post it under the note about the burmese.
    
    cin
    

    Ahem...
    
    Having offered the story, I find it was in a book about Burmese
    that I once borroewed, and do not have access to. So I can't give
    the details, but will try to recall the basic outline.
    
    Basically, when Burmese cats first appeared on the scene ( a cat
    called Wong Mau was taken from Rangoon to the US in 1930, and all
    Burmese cats are descended from her), many people were not impressed,
    and said "that's a poorly-marked Siamese" when confronted by Burmese.
    This was not helped by the fact that Burmese had to be bred with
    Siamese in these early years, as there were not enough Burmese around.
    Eventually, anti-Burmese feeling became so strong that CFA suspended
    registration of Burmese cats, in 1947. To get over this, breeders
    deliberately went away from the Siamese body type, more towards
    the American shorthair type, so that by the time the breed was
    re-admitted by CFA, in 1953, it was a very different-looking cat.
    Burmese cats had already been exported to Europe, with the result
    that rest-of-the-world Burmese look a lot like the "original" Burmese,
    and seem almost a different breed from American Burmese.
    
    That's the best I can do, hope it's clear enough. Our Burmese, by
    the way, are in body type very like the "old-fashioned" Siamese,
    with a moderately-foreign body type. They are also very popular
    -definitely far more common than the Abyssinian, and in some shows
    almost as popular as the Siamese/Orientals (I notice from Dave's
    figures that the opposite is the case in the US).

    Dave, what do you know about golden Maine Coons?  Met a maine breeder
    at a show that wanted to breed goldens but had questions.  I didn't
    understand most of what she was talking about but she mentioned
    something about breeding golden maines being different than breeding
    golden persians.  Can you shed some light on this for me?  I am
    always eager to learn more about cat genetics.
    Jo

    I'll try to shed some light.
    
    There are several types of "golden" furs, at least two are recognised
    in persians.  They are golden chinchilla and shaded golden. In maines
    in CFA/TICA, golden was not truely recognised as a separate color
    (unless TICA has changed. I had one TICA judge who insisted my
    brown/white tabby girl was golden).  
    
    Genetically, the factors are the same, ignoring the undercoat fur.
    
    The genotype is A-B-D-ii, Agouti-Black-Dense-normal pigment. They
    differ from silvers in not having the inhibitor gene, and having
    a polygene to increase the yellow pigment in the agouti hairs. Goldens
    can be stated as a yellow cat with black tips on the hair (chincilla's
    at least are this way.  Silvers and Goldens often occur in the same
    litter, if the parents are not homozygote II
    
    Dave (on break from a killer demo support)
    

    Dave - Thanks for the info.  I have another question for you now.
    Is there an effort in CFA to have golden maines recognised?  Why
    would they not accept goldens in the first place.  Shaded golden
    occurs when the undercoat is white, but is the rest of the hair
    completely gold or are there other colors involved.  
    Jo

    I am owned by an all-black manx mix (possible siamese because of
    voice and head shape).  I love this little baby.  Could someone
    give me any more info on the manx breed?  More than what was said
    in an earlier note referring to genetics.
    
    Thanks in advance.
    

    I have a brown mackrel tabby Exotic Shorthair.  The color is unusual
    and when she was a kitten she was "called" many times on her color.
    Judges kept thinking she was a golden.  She has no silvers or goldens
    in her pedigree, so I don't think this is possible.  She also has
    copper eyes.  Aren't golden's supposed to have green eyes???
    
    Unfortunately I believe her color has also hurt her as an adult.
    
    Any one know what the differences between brown and golden are??
    
    I bought this cat because I thought she was neat looking!!!   
    
    purrs
    cin
    

    
    
    Let's take another look at this golden stuff.
    
    A golden genotype is A-B-D-ii, Agouti-Black-Dense-normal pigment.
    What causes the golden is a group of "not well defined" polygenes
    which increase the yellow pigment in the agouti hairs. Goldens tend
    to have heavier tipping than silvers; this is the effect of no
    inhibitor gene.
    
    The brown tabby is A-B-C-D-iiT-/t(b)t(b), Agouti-Black-full Color-
    Dense-normal pigment (either mackeral or classic). 
    
    There are two types of tabbies not recognised as colors; I've got
    examples of both.  One is the true Black tabbie, not silver, but
    not brown.  The other is the Brown tabby smoke, which causes a lighter
    and richer brown color.  The smoke can be found by ruffling the
    cat's fur backwards and see if the black hairs are black all the
    way to the base.  If not, you've got a smoke, possibly not related
    to the inhibitor gene, but to a polygene complex of sorts.
    
    As to recognised colors, I don't have my charts with me, but I think
    (?) that golden persians should have green eyes.  Unless it is a
    polygene influence, there should be no reason for then to not have
    golden eyes though.
    
    Dave

    A few of you have asked where I pull my genetics information, so
    I thought I'd run it down.
    
    I started with a strong background in bio-chemistry and worked a
    fair amount in bio-engineering.  I followed that with some course
    work in human genetics, there being no real courses in cat genetics.
    
    I read the general feline genetics books, of course.
    
    Then, I took one of Solvig Pfleuger's genetic seminars.
    
    Solvig is the TICA geneticist.  She works full time as a human
    geneticist advising people.  Her heart belongs to cats though, and
    she is one of the three best informed people in the world.  We picke
    her brains, for quite a while, including asking more questions at
    shows where she would be judging.  
    
    We followed that up by getting acquainted with Don Hunter, also
    TICA, and picked his brains.
    
    So, I rely on my notes from these well informed people, a selection
    of reference books, and the releases from Cornell and Texas A&M.
    
    If you ever get a chance to hear Solvig lecture, TAKE IT!!!!
    It'll change your views on cats.
    
    Dave