hybridisation

Things that didn't make sense earlier, like benzene make now perfect sense, orbital hybridisation brings new explanations.

When you have a hybridisation event the genes from the two populations often don’t get along too well and it takes a while for selection to remove the incompatibilities.

If it overlapped with afarensis and other australopithecines, hybridisation almost certainly would have been possible.

I think the worry is the hybrid species might out compete the native red deer, or that fewer "pure" deer of either species will be left if hybridisation continues, as the hybrid offspring will be less picky about sticking to their own kind.

However, I would take issue with this statement: "For example, domestic sheep were created by hybridisation"... it seems inconsistent with the other one: "but the initial dates and methods of the initiation of such species are not clear".

They still have masses of junk DNA and stupid path-dependencies like the appendix and the recurrent laryngeal nerve.> would a hypothetical alien race be able to detect this kind of intervention by examining future species?Yes; we've been able to tell from its genome that brewers' yeast is an ancient deliberate hybridisation of two wild yeast strains, so future aliens could presumably do the same.