Holy Geepers
Newcastle Herald
Tuesday November 14, 2006
A SHEEP plus a goat equals . . . a geep.
And I'm not just making this up: in 1984 a geep was formed after the embryos of a sheep and a goat were merged.Interspecies creations like this are called chimeras or organisms that contain at least two genetically different cells originating from separate organisms. Scientists in the UK are hoping to gain permission to place human nuclei into animal eggs to create stem cell lines that are 99.9 per cent human and 0.1 per cent animal.The words "freak show" spring to mind but the intention of the research is to study disease, perhaps even in the future being able to create organ or tissue factories for transplants into humans.Chimeras are not new there are actually numbers of these types of creatures in labs around the world.A chimera can be created from two different groups of cells from members of the same species, or two different species.Chimeras can be created a number of ways: by fusing two different embryos together; transplanting cells, tissue or organs from one species to another; or by injecting stem cells from one species into another.Chimeras can give scientists better models to study disease, especially for experiments that would be ethically difficult to conduct on humans. For example, breast cancer is being studied in Boston by US scientists who have transplanted human breast tissue onto mice.Interestingly enough chimeras made from two humans do exist although a rare occurrence. The most common is when non-identical twins fuse in the womb to become one person.If the two embryos are the same sex there may be no differences apparent, but if a male embryo joins with a female embryo this can result in hermaphroditism.
© 2006 Newcastle Herald