Researchers at the National Institutes of Health have come up with the most complete and definitive canine family tree to date, NBC News reported.
They've spent more than 20 years sampling the genes of 161 breeds of dog, sequencing them and comparing them to show how breeds were mixed and matched to make new breeds. The genealogy also gives a rough timeline and geographic map of what came from where.
"It's very subtle variation in small numbers of genes that account for that very large difference in morphology that we see across breeds," said Elaine Ostrander of the National Human Genome Research Institute, part of the NIH.
The goal is to track disease-causing genetic mutations, which often translate to human disease genes, Ostrander said.