Breeding Plan for an unusual marking

[betty]

You may have seen my other thread for a strangely marked female which may be a form of mosaicism - or not. Basically she is a PEW who developed a peachy patch on her shoulder (following her moult line at 8 weeks) which went completely after about a week. She then developed a larger patch on her rump (from her waist to her tail) at her 4 months moult virtually overnight.

So, I was hoping to set up a breeding plan for her to see if we can reproduce it in any of her offsping or descendants, so I was looking for suggestions for this as this is quite new to me. I am assuming there will be a fair amount of line breeding (and I have plenty of her relatives) but seeing as there is only one of her, I want to do the best/most likely to show inheritance things first.

She is currently being bred to her father so we can ascertain her actual genetic make-up (as her mother was a PEW too). We are assuming (from the peach) that she is a RESN, but none of her siblings displayed ee colours even though her father was a Nutmeg, and there was also a 100% c+p linkage with her parents - so they didn't produce any dark-eyed colourpoints even though (genetically) they should have.

All suggestions will be most welcome.

[ashtree93]

I've been thinking about this for a while now.... Did you also say there was an uncle with interesting marks? If so, can I suggest crossing your female with the uncle.

If there is an uncle, it suggests it is carried in both sexes, so I suggest having both a male and female line going. In the future, you could cross these lines as well.

In terms of colour genetics, have you any other males that you know all of the colour genes for, or almost all of them? After the cross with dad, maybe cross her with the known colour gene male. If they are unrelated, then you can use this line for outcrossing.

Have you thought about how often you want to outcross? Are you going to intensively line breed for the markings and then outcross after achieving your desired results or a more one inbreed, one outbreed structure?

[betty]

I have never had a 'serious' plan before for one specific trait so I am not sure about the best ways to 1) encourage this marking and 2) keep the line healthy.

I would love your definitions and the practicalities of your suggestions, just so I know that I am understanding your terminology.

So how would I best have a seperate male and female line? How would I keep them seperate without introducing too much 'new' blood. Could you give an A,B C type example? And how would I keep the outcrossing line seperate if something crops up there? I'm really not sure about the whole 'seperate lines' thing when they all have the potential to have the 'peach gene'. I have seperate lines for 'blood' so we aren't all inbred, but how do you keep the lines apart when you want them to carry the same genes?

I know the genes for nearly all my coloured gerbils and most genes for the PEWs; so which genes would be best to outcross too? Is the colour important, or is it just so I know that I am not introducing any unknown genes into the mix? I am hoping the Uncle breeding will expose the c genes on my PEW as he is a Burmese (with EEPP) so he will ONLY have Burmese and CP Slates (if she's RESN) - if she carries the ch - then we shall know soon enough....

And as for outcrossing in the line - how often would you do this seeing as we don't actually know if the 'markings' can be repeated? Would you start with breeding to her dad/uncle and then breed the offspring to each other to see if you can get it to recur - in which case would I be aiming for the pairs that show the most PEWs (as this is the only colour I have seen it on so far)? Or just a random matchin-up in these early stages

Do you have any example diagrams of potential breeding patterns and which ones are best for what ends? I am a total line-breeding newbie here!

Thanks

[ashtree93]

I was only asking about the colour genes as you mentioned not knowing the PEWs. It would be interesting to see if it is linked to a particular colour.

I personally have never linebred, but I did study commercial genetics and breeding schemes at uni as part of my vet genetics module.

With this, the main aim is to see if it is hereditary. Is there any particular reason why you think it's inherited from the father, or was this only due to the PEW being female?

I would go with an intensive scheme for now to determine if the markings are passed on to the next generation. Otherwise, you may be undoing what you achieve when you outcross.

I'll make a diagram of what I said on excel and upload it in a bit once it's done.

[betty]

Thanks for that - I'm looking forward to seeing it.

As for the dad - I was only breeding to him first as it seemed the logical first inbreeding step - and as he is a Nutmeg (aaCc(chm)eePpU*) it would help me to see if SHE was ee too - we are only assuming she is a RESN under there and had assumed the mother wasn't carrying the single e. So if Apache (aa c(chm)* *e pp **) gets anything other than ee pups from him then I have no idea where the peach colour came from? Also, he is C+chm so we should get more PEWs from them if that is the weakest link?

I will be checking the maternal side and the presence of ch when I breed her to that Burmese Uncle (aac(chm)c(chm)EEPPUu). I would rather not breed from Apache's mother again (aa c(chm)* E* pp *u) as she seemed to find the whole 'mother' thing rather stressful (from my anthropomorphic observations anyway), but I do have her sisters if necessary (another PEW and a Sapphire).

Thanks again.

[ashtree93]

My hand drawn picture was really messy. My suggested steps so far are:

1. Recross mum and dad to see if anymore are made
2) cross the marked pew with a) dad b) uncle

See of anymore are produced.

If they are

3. Redo the crosses that caused them
4. Select the marked offspring for crosses

[Shooting Star]

Jul 29, 2014 0:38:08 GMT -8 ashtree93 said:

If there is an uncle, it suggests it is carried on both sex chromosomes, so I suggest having both a male and female line going. In the future, you could cross these lines as well.

Why would it be carried on a sex chromosome at all? You brought that up in Reeses' thread as well. Sure, it's possible, but not likely. Gerbils have 44 chromosomes, only 2 of which are sex chromosomes. That's a 95% chance that it would be on an autosomal chromosome, not factoring in the actual size of each chromosome. Sex-linked spontaneous mutations are fairly rare-- for rodents, the only example I can think of is sex-linked brindle in mice.

[ashtree93]

I didn't comment on the other thread... That wasn't me that said about Sex chromosomes in thst one.

I guess I worded it wrong on this one. I should have said it is carried in both sexes rather than anything to do with chromosomes

[ashtree93]

Ninestone brought it up in the other thread

[Shooting Star]

Whoops, you're right! Sorry about that. The point stands, though: very few mutations are carried by only one sex.

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