Question about melanism

Sylphie · 04-08-15, 07:38 AM

Hi,
maybe it's very stupid, but I can't find any answers... from what I know melanism is dominant, but I'm not sure what can I got if I breed normal x melanistic.
In example I put together normal female (parents normal x normal), and melanistic male (melanistic x melanistic). Will I get 50/50, or will there be only a few percent of black, and majority of normal?

Thank you for any help!

prairiepanda · 04-08-15, 10:00 AM

Melanism can be caused by many different mutations, so it may be dominant(completely or incompletely) in some species and recessive in others, or it could even occur as a sex-linked trait. If you know a breeder of melanistic russians, you should ask for their experience regarding this. Any experience with melanism in other species is not applicable, unfortunately

EDIT: Apparently melanism in Elaphe dione is recessive. It's possible that the mechanism for melanism in Elaphe shrenkii (Russian rats) is the same, if they are as closely related as the taxonomy assumes. I don't know whether the Elaphe genus has been assessed for genetic relation, though, so I can't say how strong this evidence is.

Sylphie · 04-08-15, 10:10 AM

prairiepanda, huh, that's sad, I was also thinking about breeding melanistic dione's (in distant furture), but if it's really so varied, then I must carefully look for information regarding each species.

prairiepanda · 04-08-15, 11:06 AM

In the case of diones, since the melanism is recessive, a normal type and melanistic pair would produce all normal het melanistics, two het parents would produce 25% melanistics(with the others being 66% poss hets), a het and melanistic pair would produce 50% melanistics(with the others all being definite hets), and two melanistic parents would produce only melanistics.

But any other species you might work with you'll have to research separately. Closely related species might utilize the same colour determination mechanisms, so if you can't find any data on a certain species then you can guess based on related species but that is not a guarantee. I would not be surprised to find that melanism is recessive in E schrenckii as well, but a breeder could give you a definite answer.

Sylphie · 04-08-15, 11:14 AM

prairiepanda, thank you very much!
So, in case of dione's the best for me will be 2 melanistic, or het and melanistic, and I must question some E.schrencki breeders... but I'll buy an melanistic russian anyway, so even if I fail to get the accurate information I'll still be able to try and get some experience.

Sylphie · 04-14-15, 04:57 AM

Maybe someone will need this info in future:
Okay, I found out that melanism in Russian Rats is recessive, so it will take some time to get visible melanistic from normal x melanistic. But it's still worth a try because there is rather little black Russians

Obsidian_Dragon · 04-14-15, 09:53 AM

A long time, with the rate Russians grow! You'd have to wait until the babies hit maturity and then breed the siblings together to try for homozygous babies. Worth it, of course, but definitely a long game.

I can't find anyone with melanistic Russians in the US. I'm a sad panda.

Sylphie · 04-14-15, 10:03 AM

Obsidian Dragon, I can't find anywhere when females are ready to breed, but seeing that my unsexed 2 years old is already 3 feet long I think that at 4 to 5 years old they should be ready.

And yeah, I'm planning to hold back one of the babies and breed with black parent, that way I should get 50% melanistic... but it's a long term project, and maybe I just buy an adult pair of melanistic, who knows (females are rather expensive)

I would love to send you one (in summer one of the breeders in my country should have babies, I'm planning to buy one from him), but I don't have any experience with internetional shipping.