Genetic evidence for hybridization in red oaks (Quercus sect. Lobatae, Fagaceae).
Published
Journal Article
PREMISE OF THE STUDY: Hybridization is pervasive in many plant taxa, with consequences for species taxonomy, local adaptation, and management. Oaks (Quercus spp.) are thought to hybridize readily yet retain distinct traits, drawing into question the biological species concept for such taxa, but the true extent of gene flow is controversial. Genetic data are beginning to shed new light on this issue, but red oaks (section Lobatae), an important component of North American forests, have largely been neglected. Moreover, gene flow estimates may be sensitive to the choice of life stage, marker type, or genetic structure statistic. METHODS: We coupled genetic structure data with parentage analyses for two mixed-species stands in North Carolina. Genetic structure analyses of adults (including F(ST), R(ST), G'(ST), and structure) reflect long-term patterns of gene flow, while the percentage of seedlings with parents of two different species reflect current levels of gene flow. KEY RESULTS: Genetic structure analyses revealed low differentiation in microsatellite allele frequencies between co-occurring species, suggesting past gene flow. However, methods differed in their sensitivity to differentiation, indicating a need for caution when drawing conclusions from a single method. Parentage analyses identified >20% of seedlings as potential hybrids. The species examined exhibit distinct morphologies, suggesting selection against intermediate phenotypes. CONCLUSIONS: Our results suggest that hybridization between co-occurring red oaks occurs, but that selection may limit introgression, especially at functional loci. However, by providing a source of genetic variation, hybridization could influence the response of oaks and other hybridizing taxa to environmental change.
Full Text
Duke Authors
Cited Authors
- Moran, EV; Willis, J; Clark, JS
Published Date
- January 2012
Published In
Volume / Issue
- 99 / 1
Start / End Page
- 92 - 100
PubMed ID
- 22174334
Pubmed Central ID
- 22174334
Electronic International Standard Serial Number (EISSN)
- 1537-2197
International Standard Serial Number (ISSN)
- 0002-9122
Digital Object Identifier (DOI)
- 10.3732/ajb.1100023
Language
- eng