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EVOLUTIONARY HISTORY OF THE MATING SYSTEM IN AMSINCKIA (BORAGINACEAE)
Author(s) -
Schoen Daniel J.,
Johnston Mark O.,
L'Heureux AnneMarie,
Marsolais Joyce V.
Publication year - 1997
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.1997.tb03956.x
Subject(s) - biology , outcrossing , mating system , selfing , phylogenetic tree , taxon , evolutionary biology , mating , genus , extinction (optical mineralogy) , zoology , ecology , population , genetics , demography , pollen , paleontology , sociology , gene
A survey of restriction site variation in the chloroplast genome of the annual plant genus Amsinckia , together with estimation of outcrossing rates, was conducted to analyze the evolutionary history of the mating system. Species, and in some cases populations within species, differ markedly in their mating system. Five taxa are distylous and predominantly outcrossing, or show mixed mating systems, while the remaining taxa are homostylous and predominantly self‐fertilizing. Reconstruction of the molecular phylogeny of the group places different distylous and homostylous taxa at four separate branch tips. When distyly is treated as ancestral in the group, or when the loss of distyly is assumed to be more common than its gain, the results of the phylogenetic analysis support the hypothesis that the self‐fertilizing taxa are of recent origin from outcrossing relatives. These findings are discussed with respect to theory for the evolution and breakdown of distyly and the probability of extinction of selfing lineages.