Posted: 07.04.10 18:45. Title: Sable Merle genetics

Hello,

I have a question concerning the genetics of sable merle collies and matings.
As far as I knew, the color is marked by two alleles, for example
sab/sab = pure sable,
sab/tri = darksable,
tri/tri = tricolour and
tri/mrl = blue merle.

Now, as it goes, a sable merle would be sab/mrl, right?

How can it be then, that tricolour puppies are born in a combination of sab/mrl and tri/tri?
From my calculation the puppies must then be either tri/sab (darksable) or tri/mrl (blue merle).
Are there different alleles for tri-merle and sable-merle?
Or did I simply miss something here?
I am studying biology and we are learning all that stuff about genetics, still I can not find a soloution for this problem.
Maybe some of the breeders from america can help me solve this riddle.

Thanks a lot in advance!

 Posted: 07.04.10 20:53. Title: This link might expl..

This link might explain: http://www.taliesencollies.com/Collie_Parent_Progeny_Color_Chart.html

Jenny

 Posted: 07.04.10 21:30. Title: Hi, two basic pairs ..

Hi,
two basic pairs of genes control Collie colors (simplified of course ;))

One of them determines if the dog is sable or tricolor...
SS = sable
St = sable (dark?)
tt = tricolor

The other pair controls merle. Merle is not really a color, it's a pattern. Blue-merle dog is actually a tricolor dog with merle pattern. Sable dog with merle pattern would be sable-merle. Something like this...

SS mm = sable
SS Mm = sable-merle
St mm = sable
St Mm = sable-merle
tt mm = tricolor
tt Mm = blue-merle

Sable-merle x tricolor genotype could be...

St Mm x tt mm

... both parents carry the "t" gene (tricolor) and "m" (non-merle)... so it's possible to get a tt mm - tricolor - puppy.

 Posted: 07.04.10 22:01. Title: Thank you! Nina, th..

Thank you!

Nina, this is what I meant with two different gene-pairs - so it is all cleared up now
Thanks again for your quick help

 Posted: 16.04.10 17:44. Title: Very nice explanatio..

Very nice explanation by Nina