Tuesday, June 1, 1999 Published at 00:49 GMT 01:49 UK
Fibro's a first for male cloning
Mighty mouse: Male cells can be used for cloning
The world's first male clone created using adult cells has been revealed in Honolulu - he is a mouse called Fibro.
Fibro was born at the University of Hawaii and Professor Tony Perry, who works alongside the mouse's creators, told the BBC: "It is very, very important that we have male clones."
The cloning technology used to create Fibro is called nuclear transfer. DNA from a cell is removed and inserted into an egg that has had its nucleus removed.
All previous clones produced from adult cells were female and the cells were taken from parts of the female reproductive system, such as mammary glands and ovaries.
But Fibro was produced using a cell from the tip of an adult male's tail, showing that easily gathered cells can be used for cloning.
This first male clone has been produced three years after the birth of Dolly, but the time lag is for practical reasons rather than scientific ones.
Laboratories carrying out cloning simply had female cells readily available to them, rather than male ones, because the focus of much the research was copying elite dairy cows.
Professor Wilmut says his team has never tried to produce male clones. The teams in Honolulu and Edinburgh lead the world in cloning technology.
Fibro is normal in all respects, including body weight, growth and fertility. However, he is the only one of 274 transferred embryos to survive longer than an hour after birth, showing that there is still much that scientists do not understand about the cloning process.
Fibro, named after the "fibroblast" cell from which he was probably derived, was created by Teruhiko Wakayama and Ryuzo Yanagimachi. They published their work in the journal Nature Genetics.