Hybrid male sterility in Mimulus (Phrymaceae) is associated with a geographically restricted mitochondrial rearrangement.

Journal Article

Cytoplasmic male sterility (CMS) and nuclear fertility restoration (Rf) involves intergenomic coevolution. Although male-sterile phenotypes are rarely expressed in natural populations of angiosperms, CMS genes are thought to be common. The evolutionary dynamics of CMS/Rf systems are poorly understood, leaving gaps in our understanding of mechanisms and consequences of cytonuclear interactions. We characterized the molecular basis and geographic distribution of a CMS gene in Mimulus guttatus. We used outcrossing M. guttatus (with CMS and Rf) to self-fertilizing M. nasutus (lacking CMS and Rf) to generate hybrids segregating for CMS. Mitochondrial transcripts containing an essential gene (nad6) were perfectly associated with male sterility. The CMS mitotype was completely absent in M. nasutus, present in all genotypes collected from the original collection site, but in only two individuals from 34 other M. guttatus populations. This pattern suggests that the CMS likely originated at a single locality, spread to fixation within the population, but has not spread to other populations, indicating possible ecological or genetic constraints on dispersal of this CMS mitotype between populations. Extreme localization may be characteristic of CMS in hermaphroditic species, in contrast to geographically widespread mitotypes commonly found in gynodioecious species, and could directly contribute to hybrid incompatibilities in nature.

Full Text

Duke Authors

Cited Authors

  • Case, AL; Willis, JH

Published Date

  • May 2008

Published In

Volume / Issue

  • 62 / 5

Start / End Page

  • 1026 - 1039

PubMed ID

  • 18315575

International Standard Serial Number (ISSN)

  • 0014-3820

Digital Object Identifier (DOI)

  • 10.1111/j.1558-5646.2008.00360.x

Language

  • eng

Conference Location

  • United States