Sex and Species- A Question (was Re: sex)

[Michael F. Hynes]

I think the best bet is to focus on probability of homologous
recombination as a defining characteristic of a bacterial species.
If overall DNA homology is sufficiently high that a gene from one
bacterium chosen at random is able to recombine with the homologous
gene in another bacterium, then they belong in the same species.

This definition, while not without its flaws, has the virtue of
general application to all organisms. After all when we talk about
defining animal species based on "interbreeding to produce fertile
offspring", aren't we really talking about sufficient DNA homology to
generate chromosome pairing (and recombination ?) ?