Patterns of nuclear genetic variation in the poecilogonous polychaete Streblospio benedicti

Research output: Contribution to journalArticle

Abstract

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

Original languageEnglish (US)
Pages (from-to)173-180
Number of pages8
JournalIntegrative and Comparative Biology
Volume52
Issue number1
DOIs
StatePublished - Jul 2012

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Polychaeta
genetic variation
loci
chromosome mapping
larvae
population genetics
nucleotides
linkage disequilibrium
morphs
nuclear genome
heterozygosity
deterioration
genome
animals

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Plant Science

Cite this

Patterns of nuclear genetic variation in the poecilogonous polychaete Streblospio benedicti. / Rockman, Matthew V.

In: Integrative and Comparative Biology, Vol. 52, No. 1, 07.2012, p. 173-180.

Research output: Contribution to journalArticle

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