Special Seminar - Little Worm, Big Brooms: Chromosome-scale Selective Sweeps in C. Elegans
Date: June 4, 2012
Time: 11:00 AM
Location: Bossone Research Enterprise Center, Room: 709
Joshua A. Shapiro, PhD
Visiting Assistant Professor, Biology
Bryn Mawr College
Research Specialist, Lewis-Sigler Institute for Integrative Genomics
The nematode Caenorhabditis elegans has long been one of the central model organisms in biomedical research, but almost all of the research has been conducted using only a single strain of the species. We sought to expand our knowledge of the species as a whole by examining the genomic variation present in a panel of 200 strains of C. elegans collected from around the world. We were surprised to find variation dominated by a set of very large haplotype blocks, each spanning many megabases and shared by the majority of strains worldwide. Population genetic modeling showed that this pattern was generated by chromosome-scale selective sweeps that have reduced variation worldwide; at least one of these sweeps probably occurred in the last few hundred years. Nonetheless, the remaining genetic variation includes many sites with important functional variants. This work underscores the importance of understanding population genetic variation, even in studies of model organisms.
Dr. Joshua A. Shapiro is a visiting assistant professor in the biology department at Bryn Mawr College and a post-doctoral research associate at the Lewis-Sigler Institute for Integrative Genomics at Princeton University. His current research interests include: 1) causes and consequences of genotypic and phenotypic diversity; 2) evolution of expression patterns and expression regulation; 3) genomic signatures of selection and demography; and 4) processes underlying population structure and speciation. As a research specialist at the Lewis-Sigler Institute for Integrative Genomics, Dr. Shapiro has examined global diversity of yeast using whole-genome polymorphism data, conducted genome-wide association studies of gene expression variation in yeast, designed custom microarrays for gene expression analysis and genotyping, developed methods for accurate SNP identification in large samples of individuals, and implemented database and analysis methods for short-read sequence data. Dr. Shapiro has authored or co-authored ten professional articles, including publications in the journals Nature, Genome Research, and Genes & Genetic Systems.
The Bossone Research Enterprise Center is located at the corner of 32nd and Market Streets.