A goat-sheep chimera also known as a geep all over the world is normally produced by the fusion of the embryos of both a sheep and a goat. The animal formed by this method thus has cells of not only goat but also of sheep origin. Those parts of the chimera that grow from the embryo of a sheep are woolly. Whereas those that grow from the embryo of a goat turn out to be hairy.

A goat-sheep hybrid is not at all similar to a goat-sheep chimera (some online websites wrongly label a hybrid as a chimera.). In a hybrid animal, each cell consists of a mixture of chromosomes obtained from the respective parents. In addition, the features of a hybrid are intermediate between the two parents. Chimeras (named after the mythological monster possessing a serpent’s tail, a goat’s body and a lion’s head) on the other hand are a mixture of cells that are genetically very different so as to form a mosaic comprising of mismatched parts.

About The Geep:

W.H. Dixon bred the first goat-sheep chimera in Ottawa, Canada some time around the eighties. It was inseminated artificially into three sheep and three goats. Interspecies chimeras generally are bred in the laboratory. The parent species necessary for giving birth to chimeras have to be related closely just like in the case of hybrid animals. This is necessary to ensure that the offspring is born alive and reasonably healthy.

A chimera can have either three parents (an additional sperm is fused with a fertilized egg or an unfertilized egg is fused with a fertilized egg) or four parents (there is a fusion of two fertilized eggs). In chimeras all the sets of germ line cells are not intermediate between the parents but these cells maintain the identity of their species.

A goat-sheep chimera (geep) is always fertile. However it will impart the genes of either a goat or a sheep depending on whether the reproductive organs were created from the embryo of a sheep or from that of a goat (i.e. according to the type of germ line created from the testes or ovary). Sometimes while trying to breed such goat-sheep chimeras, it is observed that only a few of them obtain the blood proteins of both the parental species. Such chimeras tend to behave like goats and mate with female goats. However in the case of male geeps, the sperms turn out to be defective in such cases.

Young geeps sometimes tend to have troubles with their eyesight. Some online websites erroneously make use of the word ‘shoat’ for goat-sheep chimeras. However, actually the term ‘shoat’ refers to a young piglet. Goat-sheep chimeras are similar to a lamb in size and shape but possess agile back legs and color patterns like a goat. It is observed that mothers of such geeps do not mind the fact that their off-springs are different as compared to other lambs.

It is believed that breeding such goat-sheep chimeras is very beneficial since doing so makes it possible to raise embryos of many endangered species by using the wombs of other suitable species.

Picture by NeonMerlin, licensed under GFDL

Leave a Reply

You must be logged in to post a comment.