Dissertation Research: Polyploidy and Androgenesis in the Invasive Clam Genus Corbicula

University Of Texas At Austin, Austin TX

Investigators

Abstract

Two species of Asian clams have been introduced into North America. These clams have an unusual asexual mating system in which all offspring are clones of the father. During mating, sperm will cause the egg to eject the entire maternal genome-essentially parasitizing the egg. Competition experiments between species will determine whether one species has been able to spread through US rivers by parasitizing the other. Across all Asian clams, several species have this type of asexuality, while the rest reproduce sexually. Analysis of DNA sequence data will reveal similarities and differences between genes of sexual and asexual species of Asian clams. These comparisons will be used to determine whether parasitism of sexually reproducing species caused this asexual mating system to spread to new species. Asian clams can become extremely abundant once established in an area, causing problems for industry by clogging water intake pipes. They also contribute to the decline of native American freshwater bivalves by displacing them in southern rivers and creeks. The outcome of these experiments will help provide information for the development of control methods. In addition, this research will increase scientists' understanding of what drives asexuality to replace sexual reproduction.