Some interesting stuff on genetics at www.q-mag.org/we-contain-multitudes-1.html and www.q-mag.org/we-contain-multitudes-2.html which seem to suggest genetics is a bit more complicated than Joe Public has been led to believe. The first link concerns a paper published in PNAS. This is that horizontal gene transfer as opposed to vertical (from mother and father and immediate ancestors) is part of the genetic make-up. Apparently all sorts of things can affect our DNA – bacteria, plants, fungi etc. Species swap DNA without them inheriting them – although vertical descent remains the most important factor (by a long way we may imagine).
The second link, research written by a rheumatologist, says we think of ourselves as the product of two biological parents and a one only roll of the genetic dice. Not true. We obtain DNA from other people – even in the womb. The source of our DNA is much more diverse that we currently allow. As such, the exchange of DNA may play an important evolutionary role.