The effects of microsatellite selection on linked sequence diversity

Area of Science:

• Evolutionary genetics
• Genomics
• Population genetics

Background:

• Genome-wide scans identify adaptive evolution loci.
• Standard scans assume simple mutation models, ignoring recurrent mutation.
• Microsatellites have high mutation rates, violating this assumption.

Purpose of the Study:

• Investigate selection effects on microsatellites with complex mutation.
• Compare detection power for microsatellite vs. single-nucleotide variant (SNV) selection.
• Identify novel targets of selection in human populations.

Main Methods:

• Simulated microsatellite selection and SNV sweeps.
• Evaluated standard scanning statistics (e.g., integrated haplotype statistic, SweepFinder).
• Compared number of haplotypes (K) and segregating sites (S).

Main Results:

• Selection on microsatellites is difficult to detect with standard methods.
• K and S comparisons show considerable power for detecting microsatellite selection.
• Identified novel genomic regions with anomalous haplotype configurations in human CEU population.

Conclusions:

• Standard genome scans often fail to detect mutationally complex targets of selection.
• Comparisons of K and S facilitate the identification of such targets.
• Anomalous haplotype configurations can indicate selection on microsatellites, as seen in MAGI2 intron 1.