Molecular mechanisms of reproduction in the Antarctic extremophile, Belgica antarctica

Abstract

By Geoffrey Finch, Biology

Advisor: Joshua Benoit

Presentation ID: PM_ATRIUM17

Abstract: The Antarctic midge, Belgica antarctica, is a wingless, non-biting midge endemic to Antarctica. It is found in the Antarctic Peninsula and South Shetland Islands. The life cycle of this midge is unusually long due to the short periods in which conditions for growth and development are favorable. The larval stage lasts for two years, and the adult stage is brief at about two weeks; adults mate in swarms, and females die shortly after oviposition. Eggs are laid suspended in a gel of unknown composition that is generated by the accessory gland. Many other aspects of reproduction in this and other midge species are not well understood. This project will characterize molecular mechanisms underlying reproduction in B. antarctica by examining differential gene expression in males, females, and larvae, as well as male and female accessory glands. In males, females, and larvae, 392, 1825, and 862 uniquely up-regulated genes were identified, respectively. For the accessory glands, 20 and 25 genes were enriched from the females and males, respectively. Gene ontology analyses were conducted to determine, where possible, the putative roles of genes differentially up-regulated between the sexes, or between whole-body and accessory gland tissues. Proteomic analyses were used to establish the composition of the egg-containing gel, and RNAseq data was used to determine the source of the proteins comprising the egg gel. Finally, a comparative analysis using genomes of several mosquito and midge species was conducted to gain insight into how conserved genes associated with reproduction are across lower flies (Nematocera).