Rat genetic question, give it a try!

[littleindiangirl]

This one is a tuffy. I have a black hooded female that I bred to my "siamese" male. I put it in quotations because we aren't sure if he's true siamese or himalayan, I'll explain later.

Anyways, the litter was this:
2 Black berkshire
3 Black hooded, even though they weren't perfect lines and a little broken
9 whitish/ creamish babies with red eyes.

I am completely positive that all the white babies were siamese/ himalayan, since they weren't a nice white color I expect albinos to be, and anyways, to be a true albino the mother would have to be a carrier correct, which isnt too hard to fathom.

This is further validated by the fact that the one female in particular from this litter has a few really light tan marks on her back, which the albino gene is supposed to completely dilute, whereas the c[h] gene only affects it to a lesser degree. And it is common for some siamese to have this spotting/banding.

And from certain angles it even looks like she has a white hood! It's really tough to explain, because it could just be a reflection from her longer guard hairs or something. Both my boyfriend and I have noticed from time to time. When your looking for it, it gets harder to see I guess.

Anyways, I'm trying to get some genetic background on my 2 breeders from this litter, and I'm stumped on whether or not my boy is a siamese or a himalayan. It seems more plausible that he is himalayan, because I can't see these 2 rats from different backgrounds to both carry the c[h] gene. I would expect albino to be more common than c[h].

Even more boggling is that the female has to be also Rr
and he is either hooded, or carries it, for the hooded blacks.

Help me figure out this mess!

[catawhat75]

I really am not good on rat genetics yet so this site has always helped me.

http://www.afrma.org/pdf/colorchart.pdf

[Flagg]

Not sure about the himalayan/siamese gene but the "siamese" parent is definitely also a berkshire. If he were hooded then you wouldn't have got any berkshires.

[frankykeno]

Not sure about that. I get Berkies all the time from parents that are not Berkies (at least not visually).

[littleindiangirl]

Not sure about the himalayan/siamese gene but the "siamese" parent is definitely also a berkshire. If he were hooded then you wouldn't have got any berkshires.

Yea, and he also has to have the hooded recessive gene as well because of the hooded babies. And since you say berkshire is recessive, than the mother must also be carrying the berkshire gene as well, and showing hooded. Which I was thinking can make the berkshire when modified.

LOL, this is fun aint it!

[frankykeno]

Oh it's giving me a brain ache...I need more

[Flagg]

The hooded/berkshire gene is one gene. Homozygous form is hooded, heterozygous form is Berkshire.

So for a hooded parent to have berkshire offspring, one parent must be berkshire or self. Since you also got the homozygous hooded form then you know the other parent cannot be a self, hence must be berkshire. It gets complicated with the different forms of berkshire like Irish and vari -berk but that's basically how it works.

[frankykeno]

Yep that would make sense since the berkies I get are usually from a hooded male and a couple of self females (one of the females actually does have a tiny white chest/belly mark...very tiny so perhaps she's not a technically a self).

[Flagg]

I believe that the small white chest mark that's an "Irish". My first ever female breeder was a black "Irish". It's a form of berkshire.

I've actually never been able to produce a self, 2 berkshires should result in 1/4 selfs, but all I get is berkshires and hoods.