cloning pioneer jerry yang dead at 49

Xiangzhong "Jerry" Yang, a stem cell scientist who successfully cloned the first farm animal in the United States, has died after a long battle with cancer of the salivary gland. He was 49: Stem cell, cloning expert Jerry Yang dead at 49.

Yang, director of the Center for Regenerative Biology at the University of Connecticut, died Thursday at Brigham and Women's Hospital in Boston.

In 1999, Yang successfully cloned a cow named Amy, the first cloned farm animal in the United States. (The world's first cloned animal was Dolly the sheep, created in Scotland in 1996.)

His research helped determine that cloned farm animals were safe to eat, and also helped explain how old cells can become young again when fused into embryos or eggs stripped of DNA.

Yang died, however, before achieving one of his dreams: the cloning of a human embryo for potentially lifesaving stem cells, the material that could one day repair tissue damage, replace organs, and reverse degenerative diseases. More here: Cloning pioneer Xiangzhong 'Jerry' Yang dead at 49.