Talk:Evolution/Gene flow

Gene flow is the exchange of genetic variation between populations, most commonly of the same species, in which case it is either the migration of organisms, or some substitute such as pollen, between populations. However, gene flow can also happen between different species: Where two closely-related species have adapted for different environments, hybrids may form along the border between those environments; [Source: One of Gould's books. Alas, I forget which.] plants commonly hybridize (for instance, most commercially-grown wheat is a hybrid of three different species); [expand this a bit, I think] and bacteria can share plasmids (small rings of DNA) coding for beneficial traits even between very distantly-related species.

Horizontal Gene Transfer

Note: We should make clear that hybriidisation is a type of HGT, but it's confusing to lump it all together, so let's deal mainly with the bacterial and mitochondrial/chloroplastic types here