The coat color patterns found among dogs is not due to mutations and selection during domestication, but are far older, Newsweek reports.
An international team of researchers analyzed variation within regulatory regions of ASIP gene, the Agouti gene that controls the distribution of yellow and black pigments in mammals, among hundreds of dogs. As they report in Nature Ecology & Evolution, the researchers found structural variants affecting ASIP lead to five broad, distinct coat patterns. The haplotype combination linked to one of these patterns, dubbed dominant yellow, is also found among arctic white wolves, and a phylogenetic analysis suggests the trait arose in a wolf that diverged from grey wolves about 2 million years ago.
"While we think about all this variation in coat color among dogs, some of it happened long before 'dogs' were dogs," first author Danika Bannasch from the University of California, Davis, says in a statement. "The genetics turn out to be a lot more interesting because they tell us something about canid evolution."