10 September 1999

No Bull

by Kate Melville

Scientists at Texas A&M University have successfully cloned what is believed to be the first calf cloned from an adult bull,. Their research has implications for the cattle industry as well as for the future applications of cloning technology.

The original bull - a 21-year-old Brahman was named "Chance", is the oldest animal ever cloned. His offspring has been named "Second Chance" and displays identical markings as his father and has identical DNA.

Researchers Jonathan Hill and Mark Westhusin achieved the cloning as part of a year-long project. According to Jon Hill, "The owners of Chance, who are from LaGrange, Texas, wanted to have their prized bull cloned because of his unusually gentle nature, and they considered the cloning effort a good opportunity to see if an identical copy of Chance might also have such an easy going disposition,".

Chance, was unable to reproduce naturally because of the removal of both diseased testicles two years ago. Therefore, cloning was the only option for preserving his genetics. "Second Chance is obviously an intact male and should be able to sire offspring when he reaches puberty,"

Unfortunately Chance died a few months ago at age 21, shortly before his DNA was used to produce Second Chance. Hill said there is considerable interest in keeping track of Second Chance throughout his lifetime because of the age of the cells used to clone him. This is important because of revelations that the DNA of Dolly, the first cloned sheep, had some characteristics of the older cells that were used to generate her.

Joh Hill explains, "The chromosomes, which package the animal's DNA, have some special DNA at their tips called telomeres. These small pieces of DNA help to protect chromosomes from damage. Very young animals have long telomeres, but as the animal ages, the telomeres are worn away.

We should know in a month or so if the telomeres of Second Chance are like those of the 21-year-old bull used as the source of the cells for the cloning process, or if they are more like those of a normal newborn calf."

This successful cloning effort could have significant impact on the cattle industry worldwide, as well as potentially creating breeding opportunities with other animals.

"This could lead to new opportunities in cattle breeding, and for that matter, other animals," Hill believes.

Hill a veterinarian trained in Australia is also a member of another research team led by Westhusin that is involved in the Missyplicity Project, the first-ever attempt to clone a dog. The Missyplicity Project is a 2-year effort to produce the first cloned dog. The anonymous sponsors of the project have invested $2.3 million to produce a clone of their pet dog, Missy, a mixed breed border collie. A team of about 20 researchers is working on the Missyplicity Project, and some of the knowledge gained by Second Chance is helping to advance that research.