In 1932, two University of Michigan fish ecologists, Carl and Laura Hubbs, reported in Science that they had the first experimental proof of a clonally reproducing vertebrate. What they found in the lakes and streams of northeastern Mexico and southern Texas was a small, live-bearing fish called the Amazon molly that appeared to have sex, but gave birth to only females.
The Amazon molly (Poecilia formosa) is not named after the river, but rather for a mythical tribe of female warriors that used males from neighboring tribes to reproduce, and then killed the sons. The all-female Amazon molly also needs to mate with males of related species, but unlike the mythical Amazons, no male offspring are born. Mating simply triggers the females' egg cloning process, and the sperm do not normally contribute genetic information to the next generation.
Researchers say that this bizarre fish came about at least 100,000 years ...
