Sunday, March 28, 2010

Crossbreeding goats and sheep Equals a GEEP

Crossbreeding goats and sheep
It looks like a zookeeper's prank: a goat dressed in a sweater of angora. But the odd-looking creature that appeared on the cover of the journal Nature last week is no joke. The animal is a crossbreed of two entirely different species, a goat and a sheep. Inevitably, it has been dubbed a geep.
Now 18 months old and thriving, the geep was produced by the latest tricks of embryo manipulation. Scientists at the Institute of Animal Physiology in Cambridge, England, mingled new embryos from both sheep and goats when each consisted of no more than four to eight cells. Ultimately, these were placed in the wombs of surrogate sheep or goat mothers and allowed to grow to term. Such hybrids are called chimeras (after the mythic monster with a lion's head, goat's body and serpent's tail).
Because each embryo came originally from the fertilized eggs of both a goat and a sheep, the animals had four parents.
The Cambridge experimenters produced a total of six animals with characteristics of both sheep and goats. Only one of them, however, had blood proteins from both species. That animal behaves like a goat and has even tried mating with female goats, but like another hybrid, the mule, its sperm are defective. At Justus-Liebig University in Giessen, West Germany, other embryo manipulators also reported producing goat-sheep.
Though such experimenting is sure to trigger debate, scientists point to practical benefits: it should make it easier to rear embryos of endangered species in the wombs of other species or even create hybrids as valuable as the indomitable mule.