The origin of new alleles

I would agree that it isn't impossible (maybe not even "far-fetched") that a gene could somehow be carried across the species barriers. However, my limited understanding of the terminology makes me think that a "endogenous retrotransposon" is not a gene.That is, it does not produce any messenger RNA or protein products. This makes it much more likely that it could be succesffully carried over.If an actual gene was carried over and produced proteins there is, I'd guess, a pretty high probability that it could kill the receiving cell and go no further. Again,I'd agree it may not do so and the jump isn't impossible.I guess I'd have to review the whole darned thread to figure out why that matters much.