Spatially and temporally varying selection on intrapopulation quantitative trait loci for a life history trade-off in Mimulus guttatus.

Journal Article (Journal Article)

Why do populations remain genetically variable despite strong continuous natural selection? Mutation reconstitutes variation eliminated by selection and genetic drift, but theoretical and experimental studies each suggest that mutation-selection balance insufficient to explain extant genetic variation in most complex traits. The alternative hypothesis of balancing selection, wherein selection maintains genetic variation, is an aggregate of multiple mechanisms (spatial and temporal heterogeneity in selection, frequency-dependent selection, antagonistic pleiotropy, etc.). Most of these mechanisms have been demonstrated for Mendelian traits, but there is little comparable data for loci affecting quantitative characters. Here, we report a 3-year field study of selection on intrapopulation quantitative trait loci (QTL) of flower size, a highly polygenic trait in Mimulus guttatus. The QTL exhibit antagonistic pleiotropy: alleles that increase flower size, reduce viability, but increase fecundity. The magnitude and direction of selection fluctuates yearly and on a spatial scale of metres. This study provides direct evidence of balancing selection mechanisms on QTL of an ecologically relevant trait.

Full Text

Duke Authors

Cited Authors

  • Mojica, JP; Lee, YW; Willis, JH; Kelly, JK

Published Date

  • August 2012

Published In

Volume / Issue

  • 21 / 15

Start / End Page

  • 3718 - 3728

PubMed ID

  • 22686425

Pubmed Central ID

  • PMC3883364

Electronic International Standard Serial Number (EISSN)

  • 1365-294X

International Standard Serial Number (ISSN)

  • 0962-1083

Digital Object Identifier (DOI)

  • 10.1111/j.1365-294x.2012.05662.x


  • eng