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Low genetic diversity and strong but shallow population differentiation suggests genetic homogenization by metapopulation dynamics in a social spider
Author(s) -
Settepani V.,
Bechsgaard J.,
Bilde T.
Publication year - 2014
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/jeb.12520
Subject(s) - biology , metapopulation , genetic diversity , evolutionary biology , inbreeding , population , genetic variation , ecology , genetic structure , effective population size , gene flow , nucleotide diversity , genetic drift , biological dispersal , genetics , gene , allele , demography , sociology , haplotype
Mating systems and population dynamics influence genetic diversity and structure. Species that experience inbreeding and limited gene flow are expected to evolve isolated, divergent genetic lineages. Metapopulation dynamics with frequent extinctions and colonizations may, on the other hand, deplete and homogenize genetic variation, if extinction rate is sufficiently high compared to the effect of drift in local demes. We investigated these theoretical predictions empirically in social spiders that are highly inbred. Social spiders show intranest mating, female‐biased sex ratio, and frequent extinction and colonization events, factors that deplete genetic diversity within nests and populations and limit gene flow. We characterized population genetic structure in S tegodyphus sarasinorum , a social spider distributed across the I ndian subcontinent. Species‐wide genetic diversity was estimated over approximately 2800 km from S ri L anka to H imalayas, by sequencing 16 protein‐coding nuclear loci. We found 13 SNP s in 6592 bp ( π = 0.00045) indicating low species‐wide nucleotide diversity. Three genetic lineages were strongly differentiated; however, only one fixed difference among them suggests recent divergence. This is consistent with a scenario of metapopulation dynamics that homogenizes genetic diversity across the species' range. Ultimately, low standing genetic variation may hamper a species' ability to track environmental change and render social inbreeding spiders ‘evolutionary dead‐ends’.