Scientists in Texas, US, announced last week that they have successfully cloned a domestic cat. Mark Westhusin and his colleagues at the Texas A&M University report the process in the 21 February issue of Nature.

The kitten, called 'Cc', for carbon copy, is now two months old and appears to be healthy and developing normally. She was cloned using the nuclear transfer process used to create Dolly the sheep. An egg was stripped of its nucleus, which was then replaced with the nucleus of a cell taken from Rainbow, a female tortoiseshell cat. The egg was tricked into believing fertilisation had taken place and the resulting embryo was transplanted to a surrogate.

Cc is not, however, identical to Rainbow, although tests have confirmed that they have the same genetic make-up. The colours in her coat suggest she is a clone, but her pattern differs from that of Rainbow. This is because the patterns that cats develop on their coats are not wholly genetically determined, but depend on other factors during early development.

Cc is the only kitten resulting from 87 embryos originally created. This figure is said to be comparable to the success rates of cloning in other animals. It is believed that if the technique can be improved, pet cloning may one day become a realistic option. The research was, in part, funded by an American company that hopes, in the future, to provide commercial pet cloning services. Whilst the development has been welcomed by some, including those who believe the technology will be useful in the preservation of endangered species or socially valuable animals such as rescue dogs, others who are concerned with animal welfare do not welcome the idea, especially if it brings the possibility of commercial pet cloning closer.