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Rabbit Coat Structure Genetics

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Rabbit Coat Structure Genetics

Post Number:#1  Unread postby StartFromSeed » Sat Sep 05, 2020 9:46 am


Most of the conversation about rabbit genetics by hobbyist breeders is about color and pattern, but there's a whole third category worth diving into which is coat structure. While the woolly angora and soft, short furred rex are fairly common and popular, there's actually a collection of coat modifier and structure genes that I have found in my research which I wanted to share with you!

Fur Loss/Reduction Loci

The F Locus controls the Furless gene.

Most rabbits are genetically FF and display as normal. A rabbit with one furless gene Ff will often display some balding as a baby, but that will usually grow in. Some heterozygous rabbits will display no balding at all. A rabbit with two furless genes ff will be mostly or completely bald. Generally speaking, ff rabbits have reduced fitness so it is not recommended to be bred for.

F: Normal coat.
f: Furless.

The N Locus controls the Naked gene.

There exists a second mutation separate from furless called naked. While a furless rabbit will often be completely bald, a naked rabbit will be approximately 90% bald.

N: Normal coat.
n: Naked.

The Ps Locus controls the Pelt Loss gene.

Pelt loss rabbits possess hair follicles in the skin, but premature, excessive keratinization hinders the emergence of the hair. The recessive mutation leads to thick skin. There are two variants of this condition.

Ps-1: Normal coat.
ps-1: Absence of wool hairs, less pronounced than furless.
Ps-2: Normal coat.
ps-2: Absence of underwool hair, coat thicker than in ps-1.

The Wh Locus controls the Wirehair gene.

Rabbits with Wirehair only grow guard hairs, without undercoat hair. It is due to a semidominant mutation that is a less severe form of the naked/furless mutation. The amount of grown hair varies from one individual to another; the density of the fur is, however, lower than that of a normal rabbit (hypotrichosis). A similar condition has been observed in rabbits in Japan.

Wh: Wirehair.
wh: Normal coat.

Long Fur/Wool Loci

The L Locus controls the Angora (Long Fur) gene.

The angora or long fur mutation is a result of small changes in the FGF5 gene which can disrupt its expression, leading to an increase in the length of the anagen phase of the hair cycle, resulting in phenotypes with extremely long hair.

L: Normal coat.
l: Long fur. Known for its use as angora wool.

The M Locus controls the Mane gene.

The Mane gene is a hallmark of the Lionhead breed and is an incomplete dominant mutation that causes an angora-like mane of wool to grow around the rabbit's neck. Homozygotes are called 'double-maned' and can be identified at birth by a bare pattern on the kit's sides.

M: Maned neck. Heterozygotes are single-maned and homozygotes are double-maned. Maned rabbits may also have skirts of wool on their flanks, particularly homozygotes. Heterozygotes may lose their mane with age.
m: Normal coat.

Modified Fur Loci

The R Locus controls the Rex gene.

The Rex mutation is a well-understood mutation in many animals. It is a soft, dense, shorter coat which can actually affect color display due to the difference in fur presentation. In rabbits, there are actually three known Rex mutations, r-1, r-2, and r-3, but it is generally the case that a breeder is dealing with the r-1 mutation simplified to just r.

R: Normal coat.
r: Short and soft fur.

The Sa Locus controls the Satin gene.

The Satin gene causes silky, short, rollback fur that has a unique satin sheen to it. Satin causes each hair follicle to be slightly smaller in diameter than that of normal hair, and every hair has tiny air bubbles inside that catch the light.

Sa: Normal coat.
sa: Thin, satin fur. Absence of medulla of hair.

The Wa Locus controls the Wavy gene.

The Wavy gene (also called the Waved gene) causes the fur to be wavy instead of straight. Only manifests in rex rabbits. Note: This may be related to the r3 gene, specifically.

Wa: Normal coat.
wa: Waved fur. One example is the astrex rabbit.

The Wu Locus controls the Wuzzy gene.

The coat of the Wuzzy rabbit is normal at birth, change begins to manifest around 10 days. Homozygotes take on an unkempt appearance characterized by the tips of the fur clumping and matting in a twisting fashion which gets more pronounced as more hairs get involved.

Wu: Normal coat.
wu: Wuzzy fur. Hair is sticky/twisty and matted.

I maintain this list at https://www.reddit.com/r/rabbitgenetics/wiki/structure where you can find links with sources and check out more like this. :) Did I miss any, or do you have any other information about coat structure and hair loss you'd like to share? I'm always trying to learn more!
Last edited by StartFromSeed on Sun Sep 06, 2020 1:06 pm, edited 1 time in total.

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Re: Rabbit Coat Structure Genetics

Post Number:#2  Unread postby Zass » Sat Sep 05, 2020 1:21 pm


Astrex isn't on there, but I'm afraid it's a complex gene(or combination of genes) that isn't completely understood at this time.

When I had curly coated velveteen kits, I was in a few astrex groups.
It was very hard to pin down which curl genes one was trying to work with!!! Is it astrex? Is it a novel mutation? How do we tell? :lol:
There was a lot going on with partial hairlessness attached to the curl as well. Kits that showed partial balding and outgrew it were common, but failure to thrive was also very common. Showing curl as kits and then outgrowing it also appears to be somewhat common in rex.

2669

2664

I actually dropped my project due to health concerns for the rabbits. They were numerous.

If you want a breed selected towards domestication, english lops and velveteens (which have english in them) are a good place to start!
I simply didn't have the heart to breed and cull for health with the velveteens however, every kit was incredibly sweet and precious. Intentionally breeding genetics that caused them suffering, and then losing or having to cull them for those issues was too much for me. :(
I discontinued breeding that line and kept the dam who threw those kits (Mucky) as a pet for her entire life time.

I'm open about being a meat raiser, but I raise only healthy animals and cull them painlessly, They never "suffer" a day in their lives. I feel that producing kits that would suffer is much worse than raising them cleanly for meat.

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Re: Rabbit Coat Structure Genetics

Post Number:#3  Unread postby StartFromSeed » Sun Sep 06, 2020 1:07 pm


Yeah, Astrex is weird. I mentioned it in Wavy/Waved; as of writing this the closest I could get to an understanding of it was that it was r3r3wawa, but even that's probably only partially true or a simplification.

I imagine the reason most places only bother talking about rex, angora, and satin is that most of the rest of these structure genetics aren't really for the best. They definitely seem to have complications, and furless is even usually fatal (although I'm not clear entirely on if that's just because of the environment being subideal for furless or if it's more insidious.

Funny you should mention Velveteen Lops though; I was just talking to a local breeder and am tempted to pick up a harlequin one from her. Right now I don't think my rabbitry has any rex genes in it though, and I'm not sure I want to introduce that just yet. I kind of like the standard coat. I'm sure I would also like the rex coat but tracking who's a carrier and who isn't so that I'm not surprised down the line, and also wanting to maybe breed two rabbits for colour purposes but end up passing along a rex gene that I'd need to cull out later, I dunno, not something I want to take on right now. They're also smaller than my meat breeds and since I don't always sell out of cull bunnies, I don't want to diminish carcass size right now; in fact, I'm trying to breed towards larger rabbits, mostly (Darius the Continental Giant seems super chill!) But so long as the breeder is in business nearby I can always get one later!

EDIT: Been reading the Handbook of Genetics Vol 4 chapter on rabbits. Apparently Wirehair is actually semidominant, just fixed the original post. I'm guessing by this author's use of semidominant that there's a difference between homozygotes and heterozygotes but it doesn't clarify.

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Re: Rabbit Coat Structure Genetics

Post Number:#4  Unread postby hotzcatz » Tue Sep 08, 2020 2:57 am


There's got to be more than just 'll' for angora wool. Other than the long wool, the different breeds of angora have different types of wool and some have fluffy ears and faces and some don't.

How do we find out what the genes are? Just sort of name them ourselves? I'm guessing the fuzzy faces on the English are a recessive gene since that's one of the first things that vanish in a crossbred angora. Would it be 'ff' for face 'furnishings'? F_ for clean faces?
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Re: Rabbit Coat Structure Genetics

Post Number:#5  Unread postby StartFromSeed » Tue Sep 08, 2020 7:13 am


Well, f is already in use for furless so you couldn't use that, but generally alleles are named by those who discover the gene. However, in order to claim that face furnishings are a gene you have to prove they follow basic Mendelian inheritance (or that they're sex-linked) and that it's actually a distinct gene, and not just a gene modifier. Like, we know rabbits with high rufus appear more red than rabbits with low rufus but we know it's not a distinct gene, there's no 'ru' gene. Just like we know rabbits that display lower white--less white patterning in Enen rabbits, like booted bunnies--have blanket or plus modifiers, there's no booted gene, but booted bunnies tend to have more booted bunnies, unless bred with a very high white rabbit, with spot or minus modifiers. Probably the amount of furnishings and different types of wool are modifiers on the ll gene, but all wooled rabbits (as far as has been shown, for now) carry the same gene mutations, ll, and can be shown definitively by breeding them together, or breeding them out and breeding them back in. Breed a wool rabbit to a standard and it'll always be an Ll heterozygote; breed two Ll heterozygotes and you'll always have an average 1:2:1 ration of LL, Ll, ll rabbits.

They say that the blanket/spot (plus/minus) modifiers tend to get reenforced when you breed brokens or solids togethers. A broken bred to a rabbit from a long line of solids will tend to have lower white bunnies, and brokens bred from a long line of brokens will have higher white. Could be the case with angora/wooled rabbits as well. If you breed out, then breed back in, you can get an ll rabbit again, but it might show less wool than a rabbit bred from true ll rabbits for generations. That follows the rules of basic selective pressure even though the trait itself is determined by a singular autosomal mutation.

Face furnishings might be a distinct mutation, but likely what you're seeing is the change in modifier/polygenes through selective breeding.

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Re: Rabbit Coat Structure Genetics

Post Number:#6  Unread postby Zass » Tue Sep 08, 2020 3:58 pm


We do know that density is caused by modifiers.
Out-crosses from angora or rex rabbits run a strong risk of losing density, even as the recessive wool or rex gene is retained and passed down, the modifiers are invisible and much harder to keep.

Although rex-mixed kits, even with standard coats, often enjoy greater density than the breed they were crossed to.
(A good example of first generation visible modifier genes at work. )
It's still likely to be less dense than pure rex kits.

I've never played with the genes on angora faces. I do know that some french angora tend towards more face fuzz, and some less. Pretty much always less than the face fuzz on english angora. (Could be the result of more recent outcrosses to english in some french bloodlines.)

I also know that the amount of guard hairs is modifier controlled. With french angora tending towards more guard hairs, and english less.

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Re: Rabbit Coat Structure Genetics

Post Number:#7  Unread postby hotzcatz » Thu Sep 24, 2020 7:34 pm


Back in 2013, I sold a few angora rabbits to a prep school to do some genetic studies. I just found out they'd also had a Rex rabbit as part of the studies so I've sent an email to the teacher who was in charge of it to see if there was a paper written on it.

Is it possible to get a Rex Angora? Would the ll (long length) gene overpower the shorter Rex gene? Would it be good to get a Rex angora, doesn't the Rex genes cause the coat to stand on end and look plush? What would that do to a long wool type coat?

Would it have the same amount of guard hairs show up? I've met NZ meat rabbits that had angora bred into them for denser coats and several generations later some would show up with the longer 'wool'. But they didn't get the full coat structure of an angora coat. It was a disaster and all it did was mat up. Even directly after grooming, they were still a matted mess.
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Re: Rabbit Coat Structure Genetics

Post Number:#8  Unread postby Zass » Fri Sep 25, 2020 3:14 pm


Both rex and angora on the same rabbitis possible, but I've heard it's a matting nightmare. Someone had a lionhead mini rex project in pa, let me see if I can find it. They call them velvet lions:
http://www.foxawayrabbits.com/velvetlionshome.html

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Re: Rabbit Coat Structure Genetics

Post Number:#9  Unread postby hotzcatz » Wed Sep 30, 2020 10:28 pm


Thanks, Zass! I didn't see an evaluation of their rex/angora coat qualities, but I see that they were mixing them.

I just did a first grooming on a young hybrid angora doe. She's 7/8ths English, 1/16th Satin and 1/16th German. The doe is matting up much more than any of the other hybrids, not sure if I'm gonna keep her or not. She's not matting as bad as the NZ/angora crosses I've seen, but much more than the purebred English. It's also this 3rd hybrid generation that seems to be doing the matting, now that the face furnishings are starting to come back. The first hybrid cross was between a Satin/German buck (who didn't mat his wool) and one the the pure English here. Those first crosses didn't have matting issues, although they had no face furnishings to speak of, either. Their wool was coarser than a pure English, they weren't significantly larger, either.

Now we're at Gen 3 since the first cross, mating back to pure English each time and selecting for looking like English. Now we have this young doe who still doesn't have the English half dome body but a more cylindrical one of the Satin/German. She has some of the English face furnishings, but not a full set. She is also starting to mat her coat and she's just barely three months old, I think. I'd have to check the database for an exact age. Dunno if I'm gonna continue the hybrid experiment any more or not. It was originally to keep the herd from being inbred, but maybe a higher ratio of inbreeding (I'd been trying to keep it below 25%) may be the answer instead of hybrid angoras.
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Re: Rabbit Coat Structure Genetics

Post Number:#10  Unread postby reh » Sun Feb 21, 2021 2:52 am


This is an Satinangorarex: Image

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