Hundreds of people die every year because there are not enough human hearts available for transplantation. Transgenic pigs' hearts could be the answer and could be available for transplanting into humans by 2010. To produce the genetically-modified pigs' hearts, scientists tried to engineer human 'identity' tags onto the surface of the pig organs to 'fool' the immune system into accepting the organs. They did this by inserting human genes into the genetic material of pig embryos.
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