You are on a different planet.
You are unable to escape.
The home planet may have been destroyed.
You have an advanced knowledge of biology and some useful technology.
You are not bound not to interfere with the fauna as they are very primitive.
You are not bound not to interfere with the fauna as all bets are off given the catastrophic loss of culture and DNA on home planet.
You wish to preserve your DNA which may be unique.
WHAT DO YOU DO?