title: Large-scale adaptive divergence in Boechera fecunda, an endangered wild relative of Arabidopsis.
abstract: Many biological species are threatened with extinction because of a number of factors such as climate change and habitat loss, and their preservation depends on an accurate understanding of the extent of their genetic variability within and among populations. In this study, we assessed the genetic divergence of five quantitative traits in 10 populations of an endangered cruciferous species, Boechera fecunda, found in only several populations in each of two geographic regions (WEST and EAST) in southwestern Montana. We analyzed variation in quantitative traits, neutral molecular markers, and environmental factors and provided evidence that despite the restricted geographical distribution of this species, it exhibits a high level of genetic variation and regional adaptation. Conservation efforts therefore should be directed to the preservation of populations in each of these two regions without attempting transplantation between regions. Heritabilities and genetic coefficients of variation estimated from nested ANOVAs were generally high for leaf and rosette traits, although lower (and not significantly different from 0) for water-use efficiency. Measures of quantitative genetic differentiation, Q ST, were calculated for each trait from each pair of populations. For three of the five traits, these values were significantly higher between regions compared with those within regions (after adjustment for neutral genetic variation, F ST). This suggested that natural selection has played an important role in producing regional divergence in this species. Our analysis also revealed that the B. fecunda populations appear to be locally adapted due, at least in part, to differences in environmental conditions in the EAST and WEST regions.
authors.affiliation: Department of Biological Sciences, University of North Carolina at Charlotte Charlotte, North Carolina, 28223.
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Leamy
authors.affiliation: Department of Biology, Duke University Durham, North Carolina, 27705.
authors.forename: Cheng-Ruei
authors.initials: CR
authors.lastname: Lee
authors.affiliation: Department of Biology, Duke University Durham, North Carolina, 27705.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Cousins
authors.affiliation: Department of Biological Sciences, University of North Carolina at Charlotte Charlotte, North Carolina, 28223.
authors.forename: Ibro
authors.initials: I
authors.lastname: Mujacic
authors.affiliation: Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén Jaén, 23071, Spain.
authors.forename: Antonio J
authors.initials: AJ
authors.lastname: Manzaneda
authors.affiliation: Department of Biology, Colorado State University Fort Collins, Colorado, 80523.
authors.forename: Kasavajhala
authors.initials: K
authors.lastname: Prasad
authors.affiliation: Department of Biology, Duke University Durham, North Carolina, 27705.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mitchell-Olds
authors.affiliation: Department of Biological Sciences, University of North Carolina at Charlotte Charlotte, North Carolina, 28223.
authors.forename: Bao-Hua
authors.initials: BH
authors.lastname: Song
keywords: Conservation; FST; QST; endangered species; environmental differentiation; local adaptation