the sable merle debate
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The sable merle debate
seems that there are still a lot of people in this 'collie world' who have no understanding of the Merle gene. I will try to briefly explain once again. Every collie carries two allele for colour, one from the mother and one from the father. They can also carry separate modifier genes that can significantly alter the appearance of the genes they have inherited. Put simply, MERLE is a modifier gene. There is NO SUCH THING AS A BLUE MERLE GENE. The blue merle Collie is actually a TRICOLOUR that also carries a Merle gene that modifies the black by diluting it to blue. Every blue merle, regardless of the colour of its parents, has received one tricolour gene from each parent, and is itself a tricolour. However from one parent it also received a MERLE gene that modified the black and diluted it to blue. When we mate a shaded sable to a blue merle, we can produce four genetic types.