Be careful to distinguish between *hybrids*, which are offspring of matings between different species, and *chimeras*, which are the result of fusion of early embryos from the same or different species. Mules are hybrids of donkeys & horses; every cell of a mule contains both donkey & horse genes. Geeps (actually, I think there has only been one so far) are chimeras of goats & sheep; every cell of a geep is either a goat cell or a sheep cell. Hybrids can only be made from closely related species, but chimeras can be made from remarkably different ones. There have even been human-rabbit chimeras (not allowed to mature, but sacrificed at an early stage to harvest stem cells). There is said to be nothing to prevent the production of human-chimpanzee chimeras except that most humans, including even me, are squicked by the idea.

--- Joe Fineman    joe_f@verizon.net

||: The living know that they shall die, but the dead know not anything. :||