"If ethics is a molecular expression, seems to me there is no hope for the species."

hmmm.. Í'm not sure exactly why you take such a pessimistic attitude toward such possibilities, especially since even that study indicates that oxytocin only 'tends' to influence 'some' behavior.
I read almost every month of some new discovery about DNA, or some chemical 'influence' on our tendencies & behavior. All it suggest to me is that evolution is a pretty complex process and that MANY factors, from oxytocin to testosterone, can **tend** us toward various patterns.
My master's thesis was to have been on a possible (philosophical) resolution of the question of whether we actually have 'free will' and how it could be explained.....but my conclusion was to have added that, no matter what it 'seemed' to be, we still must assume that we do have freedom of choice, and that awkward 'tendencies' can be dealt with.

What I 'feel' as a human still continues, no matter what I read about possible causal influences ON that feeling.