Sheep, mice, cattle, goats and pigs have all been cloned by transfer of a donor cell nucleus into an enucleated ovum, and now we add the successful cloning of a cat ( Felis domesticus) to this list. However, this cloning technology may not be readily extendable to other mammalian species if our understanding of their reproductive processes is limited or if there are species-specific obstacles.
"First Cloned Cat is Born," Scientists Say
February 15, 2002; Washington, D.C. ( Reuters) -- "A playful, 'cute as a button' kitten is the first-ever cloned cat," researchers said Thursday. The two-month-old kitten called "CC:" is the first successful product of a program aimed at letting people clone their beloved pets at Texas A&M University in College Station. TX.
The kitten joins a growing list of animals that have been cloned from adult cells, starting with Dolly the sheep and now including pigs, goats, cattle, mice, and an oxlike creature called a gaur. "She is as cute as a button," said a spokeswoman for Texas A&M, where the work was done using a grant from philanthropist Dr. John Sperling's Apollo Group, Inc. "The kitten was vigorous at birth and appears to be completely normal," Mark Westhusin and colleagues write in their report in a letter published in the science journal Nature
The kitten is a calico-and-white short-hair that looks similar to, but not exactly like, her genetic mother. The kitten looks quite different from the tabby that gave birth to her. The scientists said "her coat coloring was unique because not only does genetics contribute to an animal's markings but also conditions in the womb." Westhusin's team said the kitten was cloned from a cumulus cell. These cells nurture the developing eggs in a female's ovary and have been used to clone other animals as well, as they seem particularly adaptable to the process.
It took the researchers 188 tries to get just one kitten. They got 82 embryos but only one cat got pregnant, with a single kitten. Westhusin said it is not clear how easy it will be to clone cats. Westhusin's efforts were funded by Dr. Sperling's Genetic Savings & Clone, Inc., set up with the intent of helping people clone their pets.
Researchers worry about the health of clones. Many cloned farm animals reportedly are healthy and normal once they survive pregnancy and birth. But the clones often have abnormal placentas, which can lead to an abnormally large fetus that often dies immediately after birth. And Japanese scientists reported this month that most of the mice they cloned died young of liver and lung problems. Experts suggest that the cloning technique used is key to getting a healthy animal.