Endler's Discovery. When evolutionary biologist John Endler began studying Trinidad's wild guppies in the 1970s, he was struck by the wide variation among guppies from different streams, even ...

Ava Fajen, Felix Breden, Mitochondrial DNA Sequence Variation among Natural Populations of the Trinidad Guppy, Poecilia reticulata, Evolution, Vol. 46 ... Examination of fish from northeastern South ...