Long Hair Genetic Question

[kashmir64]

I'm putting this question in this thread because there are more people who know about genetics.
As some of you know, one of my cats clearly has a strong Siberian influence. I always thought she had a different father because her sisters don't look a thing like her.
Question: If the mother has Siberian, is it possible that she had 2 short hair kittens and one long hair? If she was short hair and my kittens' father is the Siberian, then what are the chances that 2 different orange toms mated with her? The mother had 2 orange females and a tortie, so the males had to be orange.
I googled long hair genetics but didn't understand it very well. Could someone help me to understand how 2 kittens have short hair, pointed ears and a thin longer face and 1 kitten is clearly Siberian influenced (only question is how much). Other than two are orange and female, that's where the similarities end.

 

[1CatOverTheLine]

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Longhair genetics is fairly straightforward. L/l codes for hair length, with L - the dominant - coding for short hair, and l - the recessive - coding for long hair, meaning that to be longhaired, a kitten must inherit the recessive l from both Parents (there's a very rare recessive shorthair gene, but it's seen only in Persians, I believe - and only in Silvers and Goldens). It's entirely possible for two shorthaired cats to produce a longhaired kitten if both Parents contribute the recessive l, and equally possible that Mom will produce shorthaired kittens when both Parents don't contribute the recessive allele.

Additionally, Fibroblast Growth Factor5 (FGF5) works in concert with the recessive l as a determiner in hair length, but that's a bigger circus, with lots of extra monkeys.
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[kashmir64]

So is it possible that the mother had Siberian DNA and the other two just took on the look of the father and she (Samai) got the recessive long hair gene from dad, but took the Siberian look of mom?
I'm trying to think of this as my sister and I. I took the Seminole gene (dark hair, dark eyes, high cheekbones and olive skin) where my sister took my dads' English gene (blond hair, green eyes, pale skin).
Could it be like that? And mom was actually the Siberian?

There used to be a Siberian breeder not too terribly far from where they were found, but they seem to be out of business now.

 

[1CatOverTheLine]

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kashmir64 - In both cases, yes. Within certain parameters, the expression of individual genes is a roll of the dice, unless you're intervening with microcarriers (i.e. "gene guns").
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[lutece]

What are the specific traits that you feel demonstrate Siberian influence in your cat?

 

[kashmir64]

Thank you 1CatOverTheLine

lutece - This is what makes me think she's got Siberian. Also, other people on here said they thought probably she had some.

And this is her sister. Unfortunately, I couldn't keep the tortie.

 

[lutece]

Other than the long coat, the structure of the two cats doesn't look so different to me in the pictures. What structural differences are you seeing?

 

[kashmir64]

She is big. 25 lbs worth of big. Sister is around 10 lbs. Her ears are round with lots of hair in them. Sister's are pointed with not much hair. She has a short face. She has a triple dense coat. And man, can this cat jump. Basically, the looks and characteristics of a Siberian. Plus, like I said, at the time they were found, there was a Siberian breeder not far from where they were found.

I am not questioning whether she has some Siberian, I am convinced she does. I was wondering how her sisters had short hair.

They say a picture is worth a thousand words, but only if it's a good picture.

 

[lutece]

In the pictures I'm not really seeing a shorter head structure compared to the shorthaired girl in the pictures; their head types look pretty similar. But of course I am only looking at these pictures, I am not physically handling the cats! In general, longhaired cats with a thick coat will appear to have a shorter face, smaller ears and heavier boning because of the fur. We see this effect in Chartreux when breeders occasionally get longhaired kittens (in our breed, this recessive gene probably came from a Persian outcross that was done in 1936).

Anyway, in order to get a longhaired kitten, both parents must carry longhair, but since it is a recessive gene, the parents themselves might be either longhair or shorthair.

 

[lutece]

So is it possible that the mother had Siberian DNA and the other two just took on the look of the father and she (Samai) got the recessive long hair gene from dad, but took the Siberian look of mom?

It's a very good question, so I will try to answer it in detail!

Let's suppose that you have a purebred mother cat; her ancestors were selectively bred over many generations for specific traits. You breed her to a random-bred domestic cat. The kittens inherit half of their DNA from the purebred mother. What does this mean for how the first generation hybrid kittens will look?

For single gene inheritance it's simple. If a purebred mom has a breed-defining trait that is dominant (such as the Abyssinian's ticked tabby pattern), all her kittens will have that trait. If she has a breed-defining trait that is recessive (such as the Siberian's long hair), whether or not the first generation hybrid kittens can express that trait will depend on the DNA of her mate; they can express it if her mate is a carrier of that gene.

Most traits are not controlled by a single gene, however. When purebred cats are selectively bred over many generations, various structural traits are bred into the lines that appear to have a polygenic inheritance pattern (controlled by multiple genes and not just one gene). For this type of trait, first generation hybrid kittens are likely to be intermediate between the two parents. They will not generally express these traits as strongly as the purebred parent, because they have only half of the DNA necessary.

Examples of polygenic traits: fine boning vs. heavy boning; short face vs. long face; straight profile vs. dip in the profile; broad muzzle vs. pointed muzzle; big pointy ears vs. small round ears; large round eyes vs. long slanted eyes; large size vs. medium or small size; very thick fur vs. thinner fur, etc etc.

So, a purebred Siberian, bred to a domestic shorthair carrying the longhair gene, might certainly produce a litter of mixed longhaired and shorthaired kittens. The polygenic structural breed traits specific to the purebred Siberian would be "diluted" in these kittens; in terms of structure, you would expect the first generation hybrids to be somewhere in between the parents. You would not expect to see any kittens that had the same head and body structure as the purebred Siberian parent. You would also not expect to see any kittens that had completely different head and body structure from the purebred Siberian parent. You would expect each kitten to be somewhere in between.

If the first generation hybrid kittens then mated among themselves, however, (brother-sister matings), you would expect to see a wide range of looks. Some of these kittens would inherit a lot more of the Siberian grandparent's DNA, and might have more of the structure of purebred Siberians, while others might not inherit much of the Siberian grandparent's DNA, and would look nothing like Siberians at all.

Does that help answer your question?

 

[kashmir64]

Thank you. We have no idea who the father or mother is. They were found in a bowl on the side of the highway at around 10 days old. It is entirely possible they aren't even littermates, but since they were the same age (within days) and found together, we assume they are.

 

[1CatOverTheLine]

If a purebred mom has a breed-defining trait that is dominant (such as the Abyssinian's ticked tabby pattern)

Ta isn't dominant; T is dominant; Ta is considered a co-dominant allele by those who view the the allelic series for the Tabby coat as T>Ta>Tm>Tb, but the autosomal tri-allelic series falls apart because of the spotted pattern.

It's not tri-allelic, as shown definitively in Defining And Mapping Mammalian Coat Pattern Genes in The Journal Genetics, 2009. Ta exists as an allele of T on its own chromosome (c:B1); Tm and Tb exist apart, as specific genes, on c:A1. A modifier not yet traced, but on a third locus apart controls spotting and alternation of stripes.

Defining and Mapping Mammalian Coat Pattern Genes: Multiple Genomic Regions Implicated in Domestic Cat Stripes and Spots
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[lutece]

Yes, I've read the paper and am well aware of the findings. Ticked tabby is dominant: heterozygous ticked tabbies are ticked tabbies. They are not as clear coated as homozygous ticked tabbies, but they are still ticked tabbies (over the years I've seen some very cute half Abyssinians in the household pet classes that result from oops breedings!). You will notice that I said nothing about how many gene loci are involved in tabby patterns.