Geographical variation in postzygotic isolation and its genetic basis within and between two Mimulus species.

Journal Article (Journal Article)

The aim of this study is to investigate the evolution of intrinsic postzygotic isolation within and between populations of Mimulus guttatus and Mimulus nasutus. We made 17 intraspecific and interspecific crosses, across a wide geographical scale. We examined the seed germination success and pollen fertility of reciprocal F(1) and F(2) hybrids and their pure-species parents, and used biometrical genetic tests to distinguish among alternative models of inheritance. Hybrid seed inviability was sporadic in both interspecific and intraspecific crosses. For several crosses, Dobzhansky-Muller incompatibilities involving nuclear genes were implicated, while two interspecific crosses revealed evidence of cytonuclear interactions. Reduced hybrid pollen fertility was found to be greatly influenced by Dobzhansky-Muller incompatibilities in five out of six intraspecific crosses and nine out of 11 interspecific crosses. Cytonuclear incompatibilities reduced hybrid fitness in only one intraspecific and one interspecific cross. This study suggests that intrinsic postzygotic isolation is common in hybrids between these Mimulus species, yet the particular hybrid incompatibilities responsible for effecting this isolation differ among the populations tested. Hence, we conclude that they evolve and spread only at the local scale.

Full Text

Duke Authors

Cited Authors

  • Martin, NH; Willis, JH

Published Date

  • August 2010

Published In

Volume / Issue

  • 365 / 1552

Start / End Page

  • 2469 - 2478

PubMed ID

  • 20643736

Pubmed Central ID

  • PMC2935099

Electronic International Standard Serial Number (EISSN)

  • 1471-2970

International Standard Serial Number (ISSN)

  • 0962-8436

Digital Object Identifier (DOI)

  • 10.1098/rstb.2010.0030


  • eng