Sheep-goat chimera

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A sheep-goat chimera (sometimes called a geep in popular media) is a chimera produced by combining the embryos of a goat and a sheep; the resulting animal has cells of both sheep and goat origin. A geep should not be confused with a sheep-goat hybrid, which can result when a goat mates with a sheep.

[edit] History

The first sheep-goat chimera to be created artificially under laboratory conditions was born in 1984. Researchers fused a sheep embryo with a goat embryo. The resulting creature was a mosaic of mismatched goat and sheep parts. Those parts which grew from the sheep embryo were woolly. Those which grew from the goat embryo were hairy.

[edit] Characteristics

In a chimera, each set of cells (germ lines) keeps their own species identity instead of being intermediate in type between the parental species. It has four parents, whereas a hybrid has two parents.

A sheep-goat chimera may be fertile, but it will pass on either sheep or goat genes, depending on whether its reproductive (organs) system were formed from the goat embryo or from the sheep embryo (i.e., which germ-line formed the ovaries or testes).

The term shoat is sometimes erroneously used for sheep-goat hybrids and chimeras. The term shoat actually means a young piglet.

[edit] References