This is where molecular genetic techniques can help. Seahorses, he writes, are quite unusual in the fish world for being socially monogamous. Gender roles are sometimes reversed. Researchers already knew that males of these species receive eggs from females, fertilize them and hold them in a brood pouch until the young are born live. Avise's lab was the first to discover, using the techniques of molecular genetics, that a pregnant male often has received eggs from two or more females.
Female turtles can store sperm for years.
In one of the most dramatic examples of a bizarre reproductive behavior, female painted turtles, the geneticists found, can store and use viable sperm for at least three years following mating. Although this capability has been noted in captive animals in the past, Avise's lab was the first to document this phenomenon in nature. This amazing behavior was genetically documented in the euphoniously named fifteen-spine stickleback. In several fish species, Avise's lab showed, using genetic markers, that individual females sometimes have spawned in more than one male's nest. We're fortunate now that we have the genetic tools to assist with the job.