Format

Send to

Choose Destination
New Phytol. 2009;182(2):507-18. doi: 10.1111/j.1469-8137.2009.02767.x. Epub 2008 Feb 11.

Hybrid speciation in angiosperms: parental divergence drives ploidy.

Author information

1
Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3DS, UK. o.paun@kew.org

Abstract

Hybridization and polyploidy are now hypothesized to have regularly stimulated speciation in angiosperms, but individual or combined involvement of these two processes seems to involve significant differences in pathways of formation, establishment and evolutionary consequences of resulting lineages. We evaluate here the classical cytological hypothesis that ploidy in hybrid speciation is governed by the extent of chromosomal rearrangements among parental species. Within a phylogenetic framework, we calculate genetic divergence indices for 50 parental species pairs and use these indices as surrogates for the overall degree of genomic divergence (that is, as proxy for assessments of dissimilarity of the parental chromosomes). The results confirm that genomic differentiation between progenitor taxa influences the likelihood of diploid (homoploid) versus polyploid hybrid speciation because genetic divergence between parents of polyploids is found to be significantly greater than in the case of homoploid hybrid species. We argue that this asymmetric relationship may be reinforced immediately after hybrid formation, during stabilization and establishment. Underlying mechanisms potentially producing this pattern are discussed.

PMID:
19220761
PMCID:
PMC2988484
DOI:
10.1111/j.1469-8137.2009.02767.x
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center