Premium
Is Oligomeris (Resedaceae) indigenous to North America? Molecular evidence for a natural colonization from the Old World
Author(s) -
MartínBravo Santiago,
Vargas Pablo,
Luceño Modesto
Publication year - 2009
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.0800216
Subject(s) - disjunct , vicariance , biology , biological dispersal , molecular clock , phylogeography , disjunct distribution , evolutionary biology , ecology , population , phylogenetics , phylogenetic tree , demography , genetics , sociology , gene
Oligomeris linifolia constitutes one of the few examples of intercontinental disjunctions at the species level between the arid regions of the Old World and SW North America. The status of the American populations has been obscure, with some authors considering the populations to be introduced, whereas others believe them to be native. To clarify these conflicting opinions, we performed phylogeographic analyses using nuclear ribosomal ITS and plastid trnL‐F and rps16 sequences to infer the origin of the disjunct American populations. Two independent molecular clock approaches based on ITS and cpDNA sequences ( rbcL, matK, trnL‐F ) were used to estimate a divergence time of O. linifolia . Low levels of sequence divergence and estimates of relatively recent splits of Oligomeris lineages disagree with the vicariance hypotheses traditionally suggested to account for New–Old World disjunctions. In addition, significant genetic differentiation of American populations does not indicate a recent anthropogenic introduction. Morphological uniformity and the sharing of haplotypes between disjunct populations, together with the molecular clock results, suggest that a long‐distance dispersal event from the Old Word to SW North America may have taken place during the Quaternary, in spite of limited dispersal mechanisms in Oligomeris .