Fauna Journal Entry

Scientists Clone Endangered Cattle (April 11, 2003)

Scientists successfully cloned two endangered bantengs, a kind of wild cattle. The banteng calves were born from a cow on a farm in Iowa last week. One of the calves weighed twice as much as expected and the scientists destroyed it, fearing it would develop abnormally.

The cloning gives scientists hope that the technique could eventually be used to help save some of Earth's endangered species. Every day, about 100 species of plants and animals become extinct around the globe.

The calves were cloned from cells frozen from an animal that died more than twenty years ago. DNA from these cells was transferred into cow egg cells that had their nuclei removed. The cloned embryos were then implanted into cows. Only two of the sixteen embryos made it to birth.

Scientists caution that many challenges lie ahead in trying to save endangered species through cloning. For one thing, cloning does not result in genetic variety because all animals cloned from the same source have identical DNA. In the wild, a species needs a large pool of genes to maintain its adaptabiltiy and increase its chances for survival. Even if cloning is successful, it doesn't solve the problems such as habitat destruction that cause animals to become endangered in the first place.

The cloning experiment was a joint project of the San Diego Zoo, Iowa State University, and two genetic research companies.