More introgression with less gene flow: chloroplast vs. mitochondrial DNA in the picea asperata complex in China, and comparison with other conifers
Langue
en
Article de revue
Ce document a été publié dans
Molecular Ecology. 2009, vol. 18, n° 7, p. 1396 - 1407
Wiley
Résumé en anglais
Recent work has suggested that rates of introgression should be inversely related to levels of gene flow because introgressed populations cannot be 'rescued' by intraspecific gene flow if it is too low. Mitochondrial and ...Lire la suite >
Recent work has suggested that rates of introgression should be inversely related to levels of gene flow because introgressed populations cannot be 'rescued' by intraspecific gene flow if it is too low. Mitochondrial and chloroplast DNA (mtDNA and cpDNA) experience very different levels of gene flow in conifers due to their contrasted maternal and paternal modes of transmission, hence the prediction that mtDNA should introgress more readily than cpDNA in this group. Here, we use sequence data from both mtDNA and cpDNA to test this hypothesis in a group of closely related spruces species, the Picea asperata complex from China. Nine mitochondrial and nine chloroplast haplotypes were recovered from 459 individuals in 46 natural populations belonging to five species of the Picea asperata complex. Low variation was found in the two mtDNA introns along with a high level of differentiation among populations (GST = 0.90). In contrast, we detected higher variation and lower differentiation among populations at cpDNA markers (GST = 0.56), a trend shared by most conifer species studied so far. We found that cpDNA variation, although far from being fully diagnostic, is more species-specific than mtDNA variation: four groups of populations were identified using cpDNA markers, all of them related to species or groups of species, whereas for mtDNA, geographical variation prevails over species differentiation. The literature suggests that mtDNA haplotypes are often shared among related conifer species, whereas cpDNA haplotypes are more species-specific. Hence, increased intraspecific gene flow appears to decrease differentiation within species but not among species.< Réduire
Mots clés
ADN CHLOROPLASTIQUE
Mots clés en anglais
PICEA ASPERATA
CONIFERS
GENE FLOW
INTROGRESSION
PHYLOGEOGRAPHY
SPECIES DELIMITATION
EPICEA
Origine
Importé de halUnités de recherche