White Roborovskis

This is the place to discuss how current genes work and also any new mutations, new colours or unusual appearances.

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Re: White Roborovskis

Postby Nella » Thu Jan 14, 2010 6:36 pm

Hi! I am the one Tammy mentioned who has three white robo's too. I have 2 females and 1 male. I did have a litter from one of the female with 1 white young, but unfortunately it died when it was 3,5 weeks old. But that litter did give me the last evidence I needed for the genetics.

This is how it works (you were partly correct when you said it seems to be a dominant gene): white is a mixture of two husky-genes. There have been two mutations, one is the recessive husky gene (when you see a husky it will be 99,9% of the times be the recessive variant) and the other is the dominant husky gene (this gene is not very common... mostly because those robo's are a bit less healthy, that's why breeders selected on primarily the recessive gene). The white robo's consist of the mixture of these two genes... a white robo has 2x the recessive gene and 1x the dominant gene (your agouti male will carry the recessive gene, that's why you had white young, my white baby was also from a agouti male with an husky father).

You can see a little difference between the dominant and the recessive gene. The dominant robo has a darker colour (almost agouti). This is a link to the topic (Dutch forum): http://forum.dehamster.nl/viewtopic.php ... g#10518348. In the 3th picture you can see 2 recessive huskies at the back. Before them the white young and at the right side there is an agouti (with white spot between the eyes and slightly lighter than a normal agouti, like yours... it just shows that it carries the recessive husky gene). In the front there is the dominant husky young. It is almost as dark as the agouti, but has the same white marks as a recessive robo. On the 3th page, 4th and 5th picture there is the dominant male (father of the 3 dominant huskies who are born recently).

This also explanes the platinum mutation... I think it is the dominant husky gene mixted with 1x the recessive gene... these robo's are alike the normal dominant huskies, but will become white with age. I don't know this for sure, but I have 6 dominant huskies at the moment (3 of the white female, and 3 of the son of this female who is also dominant husky).
Nella
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Re: White Roborovskis

Postby Ed.C. » Thu Jan 14, 2010 8:50 pm

It's a very plausible theory and one of the reasons I wish to outcross to an unrelated Agouti. :) I suppose if other diluting genes appear in the future there will easily be several ways of making a Black-Eyed White robo, and ones that hopefully don't promote an unhealthy event by the combination of two types of de-pigmentation genes like spotting ones. Did your white just die suddenly for no reason, or did it seem weak in other ways? This is what is puzzling me about mine, they seem very very healthy for such high white animals. Also did you notice a lot of eye dilution too?

Seeing if my white is a double mutant and homozygous for recessive whiteface and heterozygous for dominant white face, and the cross supposedly a recessive carrier of white face, there should be a real high probability of some form of white face appearing in following litters.

Hopefully another litter may confirm your theory, but like you can see, at the moment only the white and Agouti have appeared.


Ed
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Re: White Roborovskis

Postby Nella » Thu Jan 14, 2010 9:21 pm

My white young died suddenly, just bad luck I'm afraid. It looked very healthy. The problem with whites is that they look always healthy at young age. When they get older they can get weaker, or well... they look weaker (holding the head a bit to one side and so on). My two white females are pretty small... 22 grams max, and they look unhealthy. The male instead is 40 gram (!) and lookes great! Unfortunately he doesn't like a lot of females... and the one he does like... well... still no babies I'm afraid (she is the right age, recessive husky, proven furtile family...).

That you only got white and agouti is just 'luck'. My first litter of white x agouti (carrier of recessive husky) gave only recessive husky... 6 young! The second was the litter in that topic... 2x recessive husky, 2x dominant husky, 1x agouti and 1x white. Because your male is agouti, carrier of recessive husky, there is a little change you will get so many white again. I think you just were very lucky, normally you would have change for: agouti, recessive husky, dominant husky and white (just 25% possibility I think because the female gives the recessive, but the male just for 50%, you also need dominant gene from the female which is also 50%). But if you do get white, is there a change I can get one or two from you? And I can also 'use' a dominant husky that is unrelated to mines. I'm trying to get the line healty (there is too much inbreeding with robo's... especially the whites came from a breeder who doesn't care who's mating to who), after that I'm focussing more on white. My primarely goal is now to get enough 'ground' for the white. So that means: more dominant huskies to be able to choose the best/healthiest for the line (well.. you call it pedigree in England I think?). Than I need unrelated huskies (recessive and dominant, recessive is easier than dominant, that's why I can 'use' a dominant one).

I may have more dominant huskies in some time, so if you would like some of them... or maybe even white!

With eye dilution you mean some kind of red eyes I think (sorry, my english is not very good)? My whites have red eyes, but they are very dark. It is hard to see.
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Re: White Roborovskis

Postby Ed.C. » Thu Jan 14, 2010 10:03 pm

Well yes luck plays a big part!

I'm not sure what nomenclature you guys have designated for roborovski's but if I use 'wf' for whiteface, 'DWF' for dominant white face, and '+' for the wild allele, then I'm hoping it doesn't confuse anybody!

So if your theory is correct then we have hopes for four possible genotypes and phenotypes, yes? Also according to your theory we have two separate loci to deal with.

So;

wf/wf DWF/+ = Black-Eyed White

wf/wf +/+ = homozygous whiteface

wf/+ DWF/+ = Fading whiteface (platinum)

wf/+ +/+ = (Whiteface carrier ) Agouti

So in effect these agouti pups of mine can only be whiteface carriers if the cross is dealing with two loci and i'm using a whiteface carrier to white. No pure agouti can emerge from the cross. I could outcross these agouti carriers to my whiteface line and see if this maybe the case.

Yes by eye dilution I mean they are lacking some pigment. The ones I have have quite noticeable dark ruby eyes, they are not black.

The health aspect is interesting because the mum still appears very healthy. I tested for hearing and it is normal. A head tilt usually indicates something has gone wrong in the inner ear, and is really common in high white animals. So breeding wise you would have to select strongly against this trait, but even so, and with the nature of spotting genes, it's health problems are genetic in origin, and selection usually can only minimises it's occurence.

If mine continue to show good health I will of course give some to other breeders, but if it proves that it's a weak or a poor gene I don't think i'll continue the line, and especially so if it's problematic health wise. I really don't think we should be adding health problems like head tilts, deafness, waltzing, etc or anything linked like that into the domestic robo gene pool.

Ed
Last edited by Ed.C. on Thu Jan 14, 2010 11:54 pm, edited 1 time in total.
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Re: White Roborovskis

Postby Nella » Thu Jan 14, 2010 10:12 pm

I am not very good with genetics that way, but you mean wf/wf as the male or female... an d DWF/+ for the other or how does this work? And I think you mean red-eyed instead of black eyed?
Nella
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Re: White Roborovskis

Postby Ed.C. » Thu Jan 14, 2010 10:27 pm

Well you are saying there are two forms of whiteface, a dominant form and a recessive form, but these two forms although similar are actually sitting on two different loci yes? Each mutation (dom whiteface and recessive) at these different loci have two alleles. In the wild form or pure Agouti it would be '++'. A recessive whiteface would be 'wf/wf' and a dominant whiteface would then be 'DWF/+'. Would that be right?

Also another thing you that you maybe able to clear up as I'm a little confused. Is the dominant whiteface, homozygous lethal? or is DWF/DWF a Black-Eyed White too, and dominant whiteface is DWF/+ ? The dominant whiteface appearing only as a heterozygote?

Ed
Last edited by Ed.C. on Thu Jan 14, 2010 10:51 pm, edited 1 time in total.
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Re: White Roborovskis

Postby Nella » Thu Jan 14, 2010 10:48 pm

Ok, well.. I don't know what a loci is, but I'll write it the way I think it is.

Agouti = +/+
Recessive husky = wf/wf (homozygous)
Dominant husky = DWF/+ (heterozygous, but not becoming whiter with age.... so not platinum!)
Platinum/dominant husky = DWF/wf
White = DWF/wf/wf

But the problem is that you can't see the difference between normal dominant and platinum dominant. This is only visible when they get appr. 1 year old. So if you have white x agouti (carrier for recessive husky) the dominant huskies are always platinum (if my theory is correct! not sure yet!), but when you pair that platinum to another agouti (carrier for recessive husky) there is a possibility of normal dominant husky and not platinum... but that will be hard to see (only visible if you pair that one up to a recessive husky, the young will be agouti and dominant husky if it is dominant husky and agouti, dominant husky, platinum husky AND recessive husky if it is a platinum).

I don't know yet if DWF/DWF is lethal, but I don't think so. I know a breeder here in Holland who only had the dominant gene (had many discussions with him in the time we didn't know the genetics yet... I was 200% sure husky was recessive and he was 200% sure it was dominant, lol... finally we both are right), he never had relatively small litters (so no absorbing before birth) and also not many dead. When you pair up DWF/+ x DWF/+ there is still 25% of getting DWF/DWF... so I think it also exsist in the homozygous variant. He never had white young... so DWF/DWF is not white!

EDIT: ahh.. I think I know what you mean with your genetic-sheet... ../.. is the loci for recessive husky and the other one for the dominant version. Than I agree with yours, although I think it should be red instead of black-eyed. Mine is almost the same... just a bit easier to understand :P.
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Re: White Roborovskis

Postby Ed.C. » Thu Jan 14, 2010 11:03 pm

Well if that is the case it would be a semi-dominant and not a dominant gene (if it appeared as a white when homozygous). There maybe a simple reason for no reduction in litter sizes either. Several species simply replace the homozygous lethal embryos with viable embryos. This can be seen in the Mongolian gerbil where there is never a reduction in litters sizes and often Sp x Sp can give litters as large as an unspotted cross.*

Ok that's right, so my Black-Eyed White is' wf/wf DWF/+' and the carrier would be 'wf/+ +/+' , So if we crossed the two together we wouldn't be seeing any agoutis, only more carriers (wf/+ +/+), you would agree? So again I could easily test your theory if I outcrossed one of my agouti pups to a whiteface.

Ed

edit: * on the extremely rare occasions where a homozygous SpSp gerbil is born, they completely lack any pigment (they are black-eyed whites) and usually die after a couple of days, usually as a result of severe anaemia.
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Re: White Roborovskis

Postby Nella » Thu Jan 14, 2010 11:53 pm

Yes, I agree although they still are agouti, but not pure - just carriers of the recessive husky gene! I think you may be right with the DWF/DWF... but if it is replaced it isn't harmfull, or is it?

Yes, you can test it with a recessive husky. I can (almost) tell you for sure that appr. 40% of the litter will be recessive husky and appr. 60% agouti (should be 50/50, but in all my previous litters it has been more agouti than husky... maybe just luck), but I know for sure you will be getting recessive huskies out of that litter!
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Re: White Roborovskis

Postby Ed.C. » Fri Jan 15, 2010 10:08 pm

No not harmful at all, the homozygote embryos just get replaced by normal healthy embryos.

Well hopefully if all the pups continue to be healthy and mum produce a few more litters, then we can find out if your theory is right :)

Have you any other pics of the Dominant whiteface or could you write a little guide on their differences from recessive whiteface? Maybe give them their own thread in the genetics section?

Ed
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