SEX AND OSTRACODS

In the quest to ascertain the selective agents sustaining sex, much ef fort has been directed to the studies of the origin and fate of asexua ls. Ostracod crustaceans are of particular importance to this work, as the appear to show the highest incidence of transitions to parthenoge nesis of any animal group. In addition, their excellent fossil record provides a historical perspective, suggesting that some parthenogeneti c ostracods have outmanoeuvered the Red Queen for at least 70 million years. Genetic studies are now probing the basis of such persistence a nd are providing new direction for experimental work examining this fr equent abandonment of sex.