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Hybrid speciation in angiosperms: parental divergence drives ploidy
Author(s) -
Paun Ovidiu,
Forest Félix,
Fay Michael F.,
Chase Mark W.
Publication year - 2009
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2009.02767.x
Subject(s) - biology , polyploid , genetic algorithm , ploidy , evolutionary biology , plant evolution , phylogenetic tree , divergence (linguistics) , genetic divergence , genetics , gene , genome , genetic diversity , population , philosophy , demography , sociology , linguistics
Summary• 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.