DISSERTATION RESEARCH: Effects of Reduced Population Size on the Genomics of Adaptation during Drosophila Experimental Evolution

University Of California-Irvine, Irvine CA

Investigators

Abstract

Reduced population size, and the inbreeding that results from it, is known to reduce the functional response to selection. The present research measures the genomic impact of inbreeding on selection in the common lab fruit fly. Most animal research uses laboratory populations that are inbred, but such inbred animals may not be good research models for species that have large population sizes like humans. Understanding the genomic effects of inbreeding will help elucidate the plight of small populations undergoing intense selection. This is of great importance for such applied settings as conservation since endangered species often have very small populations. The work will also help researchers understand how populations adapt to novel, stressful environments. The research involves sequencing pooled DNA from nearly 30 Drosophila populations maintained at small census sizes. Half of these populations were subjected to strong selection for starvation resistance, while no selection was directly imposed on the remainder. The functional response to strong selection has already been shown to be impaired in these inbred flies. Genomic analysis will reveal the genetic machinery that has impaired their response to selection. These genomic findings will then be compared to genomic studies of fruit fly populations maintained at much larger population sizes. The comparison will reveal the genetic basis of reduced response to selection with inbreeding.