Prof. Ya-Ping Zhang’s group has systematically studied the origin and genetic diversity of major domestic animals, including pig, cattle, yak, dog, sheep, goat, chicken, goose, rabbit, horse, donkey and camel. By using both mitochondrial and Y-chromosome DNA sequences, they demonstrated an East Asian origin of domestic dogs around 15,000 years ago, which was published in Science as a cover paper and also Mol Biol Evol. The studies also showed the Chicken and Asian Pigs originaed from East Asia.