Self-fertilization sweeps up variation in the worm genome

Area of Science:

• Genomics
• Evolutionary Biology
• Population Genetics

Background:

• Caenorhabditis elegans is a widely used model organism in biological research.
• Understanding genetic diversity is crucial for evolutionary and conservation studies.
• Previous studies have hinted at low genetic diversity in C. elegans, but comprehensive genome-wide analyses were lacking.

Purpose of the Study:

• To conduct a comprehensive survey of genetic diversity in natural populations of Caenorhabditis elegans.
• To investigate the impact of recent evolutionary events on C. elegans genetic variation.
• To identify genomic regions affected by selective sweeps and their consequences.

Main Methods:

• Genome-wide sequencing of multiple natural C. elegans isolates.
• Population genetic analyses to quantify diversity and divergence.
• Inference of demographic history and selection using population genetic models.

Main Results:

• Discovery of reduced genetic diversity across natural populations of C. elegans.
• Identification of widespread chromosome-scale selective sweeps impacting the genome.
• Strong structuring of genetic variation correlated with selective sweep regions.

Conclusions:

• Recent selective sweeps have substantially decreased C. elegans genetic diversity globally.
• These sweeps have profoundly shaped the genomic architecture of variation in this species.
• The findings have implications for future research utilizing C. elegans as a model organism.