Abstract
AbstractTraits that have lost function sometimes persist through evolutionary time. These traits may be maintained by a lack of standing genetic variation for the trait, if selection against the trait is weak relative to drift, or if they have a residual function. To determine the evolutionary processes shaping whether nonfunctional traits are retained or lost, we investigated short stamens in 16 populations ofArabidopsis thalianaalong an elevational cline in the Spanish Pyrenees. We found a cline in short stamen number from retention of short stamens in high elevation populations to incomplete loss in low elevation populations. We did not find evidence that limited genetic variation constrains the loss of short stamens at high elevations nor evidence for divergent selection on short stamens between high and low elevations. Finally, we identified loci associated with short stamens in the Spanish Pyrenees that are different from loci associated with variation in short stamen number across latitudes from a previous study. Overall, we did not identify the evolutionary mechanisms maintaining an elevational cline in short stamen number but did identify different genetic loci underlying the variation in short stamen along similar phenotypic clines.Teaser textThe evolutionary mechanisms underlying loss or retention of traits that have lost function are poorly understood. Short stamens inArabidopsis thalianaprovide a compelling system to investigate the roles of genetic drift and selection in trait loss across latitudinal and elevational clines. This study investigates the role of drift and selection in short stamen loss in 16 populations ofA. thalianaalong an elevational gradient in the Spanish Pyrenees. An investigation of the genetic loci underlying variation in short stamen number suggests mutations in different genes may cause trait loss in similar phenotypic clines within a species.
Publisher
Cold Spring Harbor Laboratory