Physaria thamnophila microsatellite dataset

Taxonomy, genetics and biogeography each make key contributions to biological conservation. However, integrating these disciplines to obtain a coherent account of the status of a taxon of concern is not always straightforward. This is the case for the cross-border endemic plant Physaria thamnophila (Brassicaceae). This US federally-listed endangered species is restricted to a set of unique geological sites just north of the Rio Grande (Rio Bravo del Norte) river in south Texas, USA. A single highly-disjunct occurrence of this species is found on a geologically and ecologically distinct site 260 km to the south, in Tamaulipas, Mexico. In this work, we quantify the genetic differentiation between the U.S. and Mexican populations using four microsatellite markers and sequences from three nuclear genes. In both sets of data, we find a high level of genetic divergence consistent with geographic isolation on a time scale of 1–2.5 million years. Further, we provide a hypothesis for the geologi..., Plant collections and DNA sampling.—All Physaria species were formerly included in the genus Lesquerella (Al-Shebaz & O’Kane 2002). Tissues were obtained from 1) laboratory-germinated seedlings, 2) herbaria specimens as listed in Appendix 1. Additional tissue collections were made from P. thamnophila populations under permit and consultation with the US Fish and Wildlife Service. We sampled all known populations of P. thamnophila in which plants were present at the time of sampling. Four populations were in Zapata County, Texas, ten in Starr County, Texas, and one in Tamaulipast, Mexico. Approximately 0.5 cm2 of tissue was used for each DNA isolation. DNAs were isolated from both fresh and dried tissue by a simple micro-scale preparation described previously (Pepper & Norwood, 2001). Microsatellite marker analyses.—Genomic DNAs from a single individual from the P. thamnophila SMR population (Starr County, Texas, U.S.A.) were used for microsatellite discovery. DNA fragments cont..., Microsoft Excel GeneAlEx ver. 6.5 (Peakall & Smouse 2012), plug-in for Microsoft Excel., # Physaria thamnophila microsatellite dataset [https://doi.org/10.5061/dryad.4b8gththr](https://doi.org/10.5061/dryad.4b8gththr) ## Description of the data and file structure This .csv file is formatted in GENALEX file format. All details on this data format can be found in this publication: Peakall, R. and Smouse P.E. (2006) GENALEX 6: genetic analysis in Excel. Population genetic software for teaching and research. Molecular Ecology Notes 6, 288-295. To use this data, import the .csv file into Microsoft Excel and open using the GENLEX Excel plug-in as described in the cited publication. Can then be converted to many other population genetic dataset formats using GENALEX (e.g. GenePop, GenoDive, Arlequin, Structure, SPAGeDI, etc). Numerical data for allele sizes refers to total fragment size. *Physaria thamnophila* is a US federally-listed endangered species. Some samples were collected based on one-time permission from private land-owners. Information on population geographic l...