|Colour may not be down to breeding
A new study has suggested that some canine colour patterns come from an extinct canine ancestor that existed two million years ago, long before dogs were domesticated.
This new research suggests that the distinctive colour patterns of dogs are not the result of careful breeding by humans.
The research, entitled âDog colour patterns explained by modular promoters of ancient canid originâ, suggests that, âNatural selection for a lighter coat during the Pleistocene provided the genetic framework for widespread colour variation in dogs and wolves.â
Professor Danika Bannasch from the University of California who co-authored the study said, âWhile we think about all this variation in coat colour among dogs, some of it happened long before âdogsâ were dogs. The genetics turn out to be a lot more interesting because they tell us something about canid evolution.â
A lighter coat would have been of benefit to this canine ancestor during the last ice age. The snowy arctic environment would have favoured a lighter coat.
Scientists assessed various forms of the gene which controls the expression of the âagouti signalling proteinâ or the ASIP gene and how its activation leads to five distinctive dog colour patterns.
In the study they write, âGenetic variation in ASIP affects colour pattern in many mammals; however, in dogs, the situation is still unresolved, in large part due to the complexity of different pattern types, epistatic relationships with variants at other loci and challenges in distinguishing whether genetic association of one or more variants truly represents causal variation or just close linkage.â
They add, âOur results show how introgression, demographic history and the genetic legacy of extinct canids played key roles in shaping diversity in dogs and modern grey wolves.â
Chris Kaelin of the Hudson Alpha Institute for Biotechnology in Huntsville, Alabama, a co-author of the study, said in a statement, âWe were initially surprised to discover that white wolves and yellow dogs have an almost identical ASIP DNA configuration.
âBut we were even more surprised when it turned out that a specific DNA configuration is more than two million years old, prior to the emergence of modern wolves as a species.â