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Does linkage disequilibrium generate heterozygosity-fitness correlations in great reed warblers?

Author:
  • Bengt Hansson
  • Helena Westerdahl
  • Dennis Hasselquist
  • Mikael Åkesson
  • Staffan Bensch
Publishing year: 2004
Language: English
Pages: 870-879
Publication/Series: Evolution
Volume: 58
Issue: 4
Document type: Journal article
Publisher: Wiley-Blackwell

Abstract english

Heterozygosity-fitness correlations (HFCs) at noncoding genetic markers are commonly assumed to reflect fitness effects of heterozygosity at genomewide distributed genes in partially inbred populations. However, in populations with much linkage disequilibrium (LD), HFCs may arise also as a consequence of selection on fitness loci in the local chromosomal vicinity of the markers. Recent data suggest that relatively high levels of LD may prevail in many ecological situations. Consequently, LD may be an important factor, together with partial inbreeding, in causing HFCs in natural populations. In the present study, we evaluate whether LD can generate HFCs in a small and newly founded population of great reed warblers (Acrocephalus arundinaceus). For this purpose dyads of full siblings of which only one individual survived to adult age (i.e., returned to breed at the study area) were scored at 19 microsatellite loci, and at a gene region of hypothesized importance for survival, the major histocompatibility complex (MHC). By examining siblings, we controlled for variation in the inbreeding coefficient and thus excluded genome-wide fitness effects in our analyses. We found that recruited individuals had significantly higher multilocus heterozygosity (MLH), and mean d(2) (a microsatellite-specific variable), than their nonrecruited siblings. There was a tendency for the survivors to have a more diverse MHC than the nonsurvivors. Single-locus analyses showed that the strength of the genotype-survival association was especially pronounced at four microsatellite loci. By using genotype data from the entire breeding population, we detected significant LD between five of 162 pairs of microsatellite loci after accounting for multiple tests. Our present finding of a significant within-family multilocus heterozygosity-survival association in a nonequilibrium population supports the view that LD generates HFCs in natural populations.

Keywords

  • Evolutionary Biology

Other

Published
  • Long-term study of great reed warblers
  • Molecular Ecology and Evolution Lab
  • ISSN: 1558-5646
Helena Westerdahl
E-mail: helena [dot] westerdahl [at] biol [dot] lu [dot] se

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MEMEG

+46 46 222 36 69

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Research group

Molecular Ecology and Evolution Lab

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Doctoral students and postdocs

Research fellows

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Luz Garcia-Longoria

PhD students, main supervisor

Samantha Mellinger

PhD students, assistant supervisor

Gustaf Ekelund Ugge

Helena Westerdahl w house sparrow