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Speciation and hybridization among Houstonia (Rubiaceae) species: the influence of polyploidy on reticulate evolution
Author(s) -
Church Sheri A.,
Taylor Douglas R.
Publication year - 2005
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.3732/ajb.92.8.1372
Subject(s) - biology , polyploid , reticulate evolution , lineage (genetic) , reticulate , evolutionary biology , genetic algorithm , phylogenetic tree , plant evolution , hybrid , gene flow , concerted evolution , introgression , genetic variation , genetics , ploidy , genome , gene , botany
Chloroplast and nuclear DNA sequence variation among populations and species was used to examine the phylogenetic history and hybridization of the North American Houstonia lineage. The ancestral species in the lineage do not show evidence of hybridization; however, the more recently derived species in eastern North America contain a wide degree of morphological and genetic variation both within and among species. Furthermore, there is a clear association between hybridization and polyploidy in the Houstonia lineage, with all potential hybrids occurring among species that contain polyploid populations. This suggests that polyploidy may break down species barriers and allow hybridization among lineages. These results indirectly support speciation models that involve genetic incompatibilities among species arising from gene silencing or genomic reorganization.