Coat colour genetics question

[NJK]

I am a student with an interest in dog breeding and was recently asked the following question:

 

"I have a black/white BC dog - the dam is sable/white and the sire is black/white. The grandparents on both sides are black/white. A lady would like to use my boy on her red bitch. What are the chances of getting sable in the litter?

 

Any help on this one would be appreciated. I understand the genetics of the solid colours, but the sable has confused me a bit.

 

Thanks.

[juliepoudrier]

Um, if they're just breeding for color, then they probably shouldn't be breeding in the first place. That said, there are lots of web sites that discuss coat color genetics. Look for stuff on shelties or collies and it will apply to border collies as well. You'll probably get some information here as well, but I think you'll also find that most folks are going to make comments like I made regarding breeding for color--it's the antithesis of what breeding border collies should be about.

 

J.

[TheStacks]

I suggest you read the sticky at the top of the General forum entitled: Read this First.

 

After reading that you will be better prepared for the responses you will get.

[Rebecca, Irena Farm]

I notice you are in Australia so I assume we are talking about show or show bred dogs. So I'll lead off with this: READ THIS FIRST

 

OK, now that we've cleared that up, for lurkers, I'll go into the color genetics, which interest me greatly. I'd normally just leave it at that but I suspect we are talking two completely different cultures.

 

Your "red" is ee red - yellow to deep tan with a black nose, right? There is a good discussion of ee yellow or red here: http://www.ashgi.org/color/yellow_aussies.htm

 

Both yellow and solid color black can be genetically black. So is "sable", which is controlled in yet another place (the "A" series). I'm assuming by sable you mean black sable.

 

"Self" colored black is dominant over most other colors, which means a black dog or bitch can carry other colors. Merle's the only one that I can remember offhand that isn't recessive.

 

So the answer is, you really have no way of knowing whether a dilute black or liver might slip through. I've noticed in Autralian, NZ, and SA breeding that dilutes seem to follow the ee yellow lines - probably because it's hard to see on the yellow body color when it's expressed.

 

I know from watching other breedings that the sable is more likely to come through in subsequent breedings if you match up tris or other sables. Sable pops up with some regularity in working lines because many excelllent working lines that we are using right now carry extensive tri - and probably some of those are actually sable and we just don't care enough about it to differentiate.

[NJK]

Sorry if my message came across the wrong way. The girl who asked the question shows BCs but doesn't breed them - it's another lady (breeder) who wants to use her dog as a stud. As sable is not a recognised colour in Australia and cannot enter the show ring, she wanted to minimise the chances of sable pups in the litter. If there was a high chance of sables, she probably wouldnt let her dog be used as a stud.

 

I don't own a BC, but thought I would pop in here to ask those who have a lot of knowledge on the topic.

 

Sorry for missing the 'Read this first' message.

 

Thank you for your replies.

[Rebecca, Irena Farm]

No problemo. I think, if we were talking about, say, collies instead, that your friend would want to procede with caution and be prepared for the possibility that good pups would be born that have to be placed as pets as they couldn't be shown. Sounds like a quick road to heartache.

 

This is why we are sort of hardliners on the whole notion of Border Collies being bred for how they look in the ring. Imagine if a fine working dog were born that were sable, and it were not possible to show or register that color? Bye-bye great working genes!