By Dr. Peter Hackett
-Yaks have 30 chromosomes, 20,000 genes, and over 3 billion base pairs in their DNA
-Yaks descended from a common ancestor of cattle, bison, banteng and gaur
-Yaks genetically diverged from cattle 4.9 million years ago
-Yaks were domesticated on the Tibetan Plateau about 7500 years ago
-This permitted human expansion in that area
-Domestication may have been via hybridization with cattle
-Wild yak and domestic yak are genetically extremely similar
-Both have small amounts of cattle DNA, about 1-2%
-Some Asian yaks have DNA that indicates recent cattle introgression