Patterns of Nuclear Genetic Variation in the Poecilogonous Polychaete Streblospio benedicti

摘要: The evolution of marine larvae is replete with transitions in trophic mode, but little known about how, at the genetic level, these are achieved. Basic parameters, including number underlying loci, their molecular characteristics, and population-genetic processes that drive remain unknown. Streblospio benedicti, an abundant benthic polychaete heritable poecilogony, provides a unique genetically tractable system for addressing issues. Individuals S. benedicti vary diverse aspects development. Some females produce small, planktotrophic larvae, whereas others large, yolky capable settling without feeding. Here, I present estimates basic features nuclear variation to lay foundations subsequent efforts understand basis poecilogony. Sequence ∼20 kb random DNA indicates nucleotide composition, 62.1% A + T, typical lophotrochozoan genomes. Population-genetic data, acquired by sequencing two loci (∼2500 bp) multiple animals each developmental morph, indicate morphs exhibit very differentiation loci. Nucleotide heterozygosity (θπ) ∼0.5-1% per site, linkage disequilibrium decays within few kilobases (ρ  ∼ 3 × 10(-3) site). These data suggest mapping association will require high density markers, identification regions elevated inter-morph hold great promise.