June 1, 2006

Greg Copenhaver (CCGS/Biology), Corbin Jones (CCGS/Biology) and Jeff Sekelsky (PMBB/Biology) have joined forces to tackle a classic genetic phenomenon called gene conversion using state-of-the-art genomic and statistical tools.  The group was recently awarded a three-year grant from the National Science Foundation to apply their combined expertise in genetics, molecular biology, bioinformatics, and statistics toward understanding the molecular mechanisms of gene conversion, how it is regulated and how it affects genome-wide patterns of linkage disequilibrium.  Gene conversion is the non-reciprocal transfer of sequence information from one chromosome to another, in contrast to crossing over, which refers to the reciprocal transfer of sequence information.  Both of these lead to a breakdown in linkage disequilibrium (LD), the non-random association of sets of alleles at linked loci, over evolutionary time.  Population geneticists have used meiotic recombination’s effect on LD to understand how species, their phenotypes, and their genomes evolve.  Recent evidence suggests that gene conversion may be as important as crossing over in breaking down LD in some genomic regions.  Several methods have been proposed to account for the effect of gene conversion on LD, but we lack a systematic study of how inter- and intra-chromosomal variation in recombination affects the power and accuracy of these methods. This type of analysis in higher eukaryotes has only become possible in recent years as whole genomes of genetically tractable metazoans such as Drosophila and Arabidopsis have been sequenced.  The group plans to use both of these organisms to measure gene conversion at multiple loci throughout the genome.  The long-term goal is to understand how meiotic recombination operates in higher eukaryotes and how it impacts the evolution of genomes.