What are the implications of genetic engineering for kashrus?
Transplantation of a few genes from a non-kosher creature into a kosher
creature doesn't make it unkosher, because its basic identity hasn't changed.
(Also, gene transplantation isn't cross-breeding, and isn't forbidden under
the laws of kilayim.) The situation would be more problematic if the
transplantation resulted in a hybrid creature, but this would require
transplantation of very many genes, and won't be feasible in the near future.
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