Re: Geneticists Breach Ethical Taboo By Changing Genes Across Generati
What does a "gene for speech" mean? Genes code for proteins, sometimes multiple proteins per gene. There's no way that a single gene could be responsible for speech, and by splicing a gene into one animal would make that creature capable of something it couldn't do before.
Yes, saying "gene for speech" is simplistic, but it's closer to reality than you might think. A couple of years ago I met a guy who studies the vocalization of songbirds. He has found that the difference between birds that can learn new songs and sounds, and those that can't is due to the expression pattern of one gene, FoxP2, in the brain. In fact, song-learning birds, humans, and other species that can learn and imitate sounds all have specific features in the promoter of FoxP2 that other species don't have. Of course, the ability to speak requires physical adaptations in the tongue, larynx, etc. and such, but the ability to learn and imitate sounds seems to be mostly, if not entirely, due to the expression pattern of FoxP2, so one could make the argument for FoxP2 being the "gene for speech".
As for the OP, what these guys did isn't exactly change genes. What they did replace the mitochondria,which has its own genome separate from the nuclear genome. For those non-biologists out there, mitochondria are essentially the powerplant of the cell. Evolutionarily, it's pretty well accepted that mitochondria were originally bacteria that developed a symbiotic relationship with eukaryotic cells and eventually just became part of the cell. For this reason, they still retain their own small genome to make some of it's own proteins, and the genes there look more like bacterial genes than what's in the nuclear genome. There are a few diseases caused by genetic problems in the mitochondrial genome, which these scientist were trying to fix. In the normal way of combining an egg and sperm, the resulting embryo has a blend of nuclear DNA from the two parents, but the mitochondria comes from the mother. Essentially what these scientists did was combine the nuclear DNA from a sperm and egg, but replace the mitochondria with that of a third individual.
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