American Fancy Rat & Mouse Association

This article is from the WSSF 2010 AFRMA Rat & Mouse Tales news-magazine.

Colors & Coats

What Kind of Marking Rat; Marked Rat Genetics; Breeding Hooded Rats
What Kind of Marking Rat

Shuron Stover, Fun Family Rodentry, San Diego, CA, e-mail
Q I have a question about a rat. I am stumped on what marking this rat has. I want to say Dalmatian but she has a stripe down her back that is throwing me off. I will attach two pictures of her: one of her as a baby so her spots are more defined and one of her now. This is a friend’s rat and she asked me and I was unsure. Her mom was a variegated/capped (her face marking was perfectly capped but she has a few spots down her back) and her dad was a hairless blazed dumbo.

Marked Rat
The rat in question as a baby.

Marked Rat
. . . and older.

A It looks like it could be some variation of Cap-Stripe. It depends on what markings dad had other than the Blaze to really say what she is as there are lots of different types of markings. Sorry I can’t be more specific. Karen Robbins

Marked Rat Genetics

Shaun Petzer, South Africa, e-mail
Q I have read all articles I can find but I still don’t get a perfectly clear picture on all the genetics. I understand colour genetics well and have been working on understanding marking genetics. I know what the basic HH, Hh, etc., is but don’t quite understand how or if these markings get carried over to the pups, i.e. if the mother is Variegated and the father is a Berkshire, it would be H'h' and Hh so the babies would come out HH', Hh', H'h, and hh'—25% for all. So 25% Self, American Berkshire 50% because Hh' and H'h are both Berks, and lastly 25% Bareback. Now what confuses me a little is these babies if bred together. Picking a pup that’s Berk from this litter and crossing it with Bareback, in squares gives you H'h x h'h' and the result is H'h, hh, hh', and H'h'—Berk, Hooded, Bareback, and Variegated—25% of each. Is this right because it doesn’t seem quite right to me that you get Variegated from 2 rats that are not Variegated at all or is this how they carry the gene. Would the results be the same if I took any Bareback and Berkshire and crossed them. Or only for this instance because the mother was a Variegated? Hope I made some sense at least. Thanking you in advance for your time.

A The codes you give are for regular Irish/Berkshire (Hh) and Hooded (hh) on the Hooded locus. Variegated is something else (N.F.R.S. has hhe or hehe for Variegated). According to the N.F.R.S. there is another Irish gene (hi) they have found in breedings of Cinnamon Pearl/Pearl rats where when two Irish (English Irish) are bred together, you don’t get any Hooded.

We are working out the genetics for Variegated/Dalmatian and with the most recent test breedings have proven that Dalmatian is a dominant trait (we gave the symbol Daldal) and it appears to also be a homozygous lethal gene that “extends” the amount of white in the coat, creating silvering and increasing white markings. We have further test breedings to do to give a more accurate answer. But I can tell you in all my years of breeding Variegated, you do not ever get Self or Hooded in the litters when breeding two Variegateds together—always head-spot Berkshire and Variegated, with some Capped type or mismarked ones. According to our genetic expert, Nichole Royer, she says:

“To all appearances the genetics of markings in rats is far more complicated than is typically described in the literature. There are more than one loci that produce white markings in rats, and the assumption that all white markings are caused by alleles at the Hooded locus is inaccurate. This is further complicated by the fact that multiple loci may produce very similar “Irish” and “Berkshire” type markings.

There is suspicion that both Variegated and Dalmatian are not necessarily alleles on the Hooded locus, but may interact with the Hooded locus in a rather complicated way. So your question really cannot be answered based on current data. Beyond the very basic “Self, Irish/Berk, Hooded, and Capped” series which has been proven, all other markings at this time should be considered unknowns. And it should be understood that some of the other markings may produce Irish/Berk type markings, so you can’t assume an Irish/Berk is being caused by the H locus.”

Breeding Hooded Rats

Norah Hobgood, Perris, CA, e-mail
Q Here are a few pictures of that young male Hooded I found in a pet shop I was just inquiring about this afternoon. As shown, his tail color goes past mid point, and he has spots on his groin, one on his belly, and one on his hip.

Is he show/breeding worthy? Will his odd spots/faults carry over to his offspring? Would he be good to breed to my female?

Hooded Rat
The young Hooded male rat in question.

Hooded Rat
The young Hooded male rat’s chest marking.
Hooded Rat
The young Hooded male rat showing his groin and belly spots.

Hooded Rat
The young Hooded male rat’s spine marking.

A Groin spots on males are fairly common though not desired. The ones on the stomach and hip are not good. His spine marking is fairly nice though a little wide and ragged at the top. The chest marking is pretty nice—just a little bit of a white streak—again fairly common—it either has the white strip going up towards the chin or the color dips down towards the belly. The left side hood is nice and clean; can’t tell on the right side. Head is very long, ears look nice and big, he looks very small for his age, and he is VERY young. He looks fine boned but some of that could be diet. Do they have the parents at the pet shop?

He would do okay at the show as far as markings but your female is better—less stray spots, decent type and substance, just needs a better head. As far as breeding quality of this little guy, I would have to see parents or see him in a couple months. When breeding marked, you don’t want to breed rats with the same faults, i.e. your female has too much color on tail, you say he has too much color on tail so their kids would be more apt to have too much color on their tails. If he is going to have good type and substance, then working against the stray spots would be easier to deal with. If he is out of fine boned stock, then I would opt for something different as type is harder to fix. Karen Robbins *

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Updated January 24, 2015