2021 Update – Blue and BEW Genes

It’s been three years since blue arrived here in Roborovski form. It’s still causing much debate among the robo breeding world.

It’s clear that it’s a simple recessive inheritance. That much we do know. It’s becoming evident that all the self blues have white bellies. How do I know this? Well, Casanova Hamstery in The Netherlands has a lovely photo of a red eye blue which has proven to be a lot more helpful than you might think. Breeding is a game of logic sometimes so we must look at every phenotype with a logical mind.

What do we know, for certain about the red eyed variety (cinnamon) of roborovski? Patterned red eyed hamsters have much brighter red eyes than non patterned animals. This is true of cinnamon Syrians and red eye variations of Campbells. I’m not the person to talk to if you need to know why, I just know that it is always true of the Roborovski.

Her red eyed blue, with a white belly, had dark eyes. Ergo, it is not patterned.

What a spanner in the works! We have a hamster that has self fur, no agouti markings on top but with a white belly. The only time this happens in other species is with the addition of the ‘fox’ or ‘otter’ genes, depending on which species you are discussing. Some species, like rats and gerbils, do not have this gene at all. I find it highly unlikely that we would find a fox gene (the white bellied version of a tan mouse) at the same time as a dilute gene.

I don’t think the UK standards committee will accept that theory. As right they should be skeptical, we have a robust system in place here that requires breeders to answer these questions.

The next problem is that blue is a dilution gene. It dilutes any black pigmentation in the coat to blue. For this coat to be SELF, it HAS to be diluting a self colour underneath. This would normally be black, as in every other domesticated species. However, we have not yet been able to get black back out, despite my having started with a black spotted robo, Jauffre.

SO…..we still need to breed an agouti blue. We still need to find out what’s under that diluted self coat. and we still need to explain why the white belly is there.. Worse case would be that the blue we see today (pictured below) is the base colour and there is no black in there. With no other animal behaving this way it will be utterly impossible to have this gene even recognised, never mind made standard.

Now to the BEW.

Exciting progress has been made with this line here. Let’s recap:-

Wikipedia, and other breeders, have made claims that black eyed white is 2x dominant white face OR 2x dominant pied or (in some cases) all four genes at once. To be clear to those of you who are new to genetics, heterozygous is a single dominant and homozygous is a double dominant.

I have managed to disprove that any of that applies to this black eyed white.

For a nice change I have had a pretty linear breeding with this and have been rather lucky I feel.

Mum Ida (BEW) paired with Bernhard (recessive pied) produced white, pied, possible dominant husky and recessive husky. This pairing on it’s own disproved the double dominant theory as Blizzard could only be white if his father was either dominant pied or dominant white face, or dominant husky as well as his mum.

Each parent gives one of each colour gene to their pups. If both parents were dominant anything, every pup in the litter would HAVE to be dominant. The presence of the recessive husky pup is enough to say this is not the case.

Blizzard’s litter, born on the 27th March 2021, further cements this. Bred to Ysabel (Agouti carrying recessive pied and blue) they produced white, pied and agouti (pictured below).

The fact that he produced white when bred to an agouti proves that this white has a single dominant or heterozygous inheritance. Further breeding is needed to establish if the gene is lethal, if it has to accompany any other heterozygous colour or if it could even be a patterned animal such as heterozygous dominant pied, selected to have no pattern.

Problems:- There are about three or four different theories circulating as to how to breed a white Roborovski. This could prove troublesome when approaching the Standards Committee to recognise the gene. What do they recognise it as? The upside to this is that we have no other white genes listed as recognised so this will be the first here.

Additionally, a red eyed white has been bred and, like the above red eyed blue, this has thrown a new spanner in the works. This red eyed white has bright red eyes. Is it hiding a cinnamon pattern or is it something new? To cover the possibility I will breed my whites to my cinnamons to see what colour the eyes are.

Notes:– It’s entirely possible that there are multiple ways to make a white Roborovski. I’ve always viewed theories about dominant colour genes in this species with a healthy dose of skepticism because I’ve never seen any at shows, and no one online has been able to adequately explain the difference between dominant pied or husky with recessive pied or husky. This has lead me to believe there are no dominant versions of these genes, rather a misunderstanding of how they got pied or husky in their litter. Recessives are sticky, and can reappear up to ten generations later having dropped off the end of a pedigree. Just because a gene is not on a pedigree doesn’t been it’s not in the animal.

To this end, I’ll be breeding to my agouti show line which definitely only carries husky to make sure I still see white before I put my stamp on my single dominant inheritance theory. As a breeder, you shouldn’t breed to prove yourself right, you should breed to prove yourself wrong. If you can’t prove yourself wrong then your theory is robust.

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