Friday, October 5 1:28 PM SGT

Australian scientists genetically determine lamb gender

SYDNEY, Oct 5 (AFP) - Australian scientists have claimed a potentially lucrative world first by creating 25 genetically engineered lambs from frozen sperm in a successful attempt to predetermine their gender.

Sydney University researchers said the lambs were the first in the world to be born using sperm sorted according to its gender-carrying characteristics, then later frozen, stored and thawed.

"This is the first time in the world lambs have been produced with sperm that's not only sorted but also frozen and thawed before insemination," a member of the team, Fiona Hollinshead, said.

Of the artifically inseminated ewes, those receiving male-producing sperm gave birth in July to eight male lambs, while those impregnated with female chromosome-bearing sperm mothered 17 females and one male lamb.

The sole male in the female chromosome group represented the research team's only failure.

The breakthrough has the potential to revolutionise Australia's multi-billion dollar lamb and wool industries -- both among the country's highest export earners.

For the first time, farmers could soon be able to apply techniques available only in research laboratories to commercial flocks.

The associate dean of the university's Faculty of Veterinary Science, Dr Chris Maxwell, said the technology could become available to Australian farmers within three years.

"While the production of offspring of the desired sex has been achieved in many species, including lambs, the commercial application of the technology requires the freezing and thawing of sorted sperm," Maxwell said.

Maxwell cited the increased flexibility the breakthrough would offer stud breeders, for instance, "who want high-quality rams for superior wool production ... to produce rams from the best females".

Another example would be the selection of female offspring, enabling farmers to improve the breeding capacity of their flocks.

The categorisation or sorting process of the sheep sperm involved separating sperm carrying female-producing X chromosomes from male-producing Y chromosomes.

The Sydney University team achieved this using a a high-speed cell sorting device.

The project is being supported by a private US-based company called XY Inc, a world leader in the research, development and commercial application of sex selection techniques in mammals other than humans.

The chief executive of XY Inc, Dr Mervyn Jacobson, described the breakthrough as "a breeders' dream".

"The birth of lambs in Australia proves the sperm-sorting technique, combined with freezing, thawing and artificial insemination, is now sufficiently robust in sheep to work outside the research lab," Jacobson said.

-- Anonymous, October 05, 2001