Natural variation in the genetic architecture of a germ stem cell niche
Presentation
Overview
Overview
Description
A fundamental goal of evolutionary biology is to understand the genetic and developmental mechanisms leading to the great diversity of organismal life histories. Comparison among distant taxa cannot easily address this issue due to high complexity; however, it is possible to investigate the genetic architecture underlying life history and developmental phenotypes within species. Here we show that C. elegans wild isolates from around the globe display extensive size variation of the germline mitotic zone (MZ), indicative of variation in the activity of the germ stem cell (GSC) niche. To characterize the molecular genetic differences explaining such variation in MZ size, we focus on two C. elegans isolates with strong differences in total germ cell number and MZ size. We constructed a panel of 144 SNP-genotyped F2 recombinant inbred lines (RILs) derived from the parental cross between these two isolates. Phenotyping of ~70 RILs and subsequent quantitative trait locus (QTL) analysis yielded a large effect QTL on chromosome II (~6.4 Mb) that acts additively with a QTL on chromosome V (~2.6Mb). We have identified a promising candidate causal variant in the chromosome V QTL and are currently working to identify the causal variant(s) in the chromosome II QTL through fine-mapping. The results of these studies will not only identify specific molecular changes underlying this quantitative reproductive trait, they also illuminate the genomic landscape underlying natural variation in a stem cell niche.
