Veterinary scientist who co-created the world's first cloned mule in 2003. The mule was named Idaho Gem and it was created to try to understand age-onset diseases in people.
He taught veterinary medicine at Cornell University.
He chose to clone a mule because mules, and other equines have lower rates of cancer than humans.
He had four children with his wife Shauna.
Like Louis Pasteur, he studied diseases.