title: A population genetic transect of Panicum hallii (Poaceae).
abstract: OBJECTIVE
  Understanding the relationship between climate, adaptation, and population structure is of fundamental importance to botanists because these factors are crucial for the evolution of biodiversity and the response of species to future climate change. Panicum hallii is an emerging model system for perennial grass and bioenergy research, yet very little is known about the relationship between climate and population structure in this system. •
  
  
  METHODS
  We analyzed geographic population differentiation across 39 populations of P. hallii along a longitudinal transect from the savannas of central Texas through the deserts of Arizona and New Mexico. A combination of morphological and genetic (microsatellite) analysis was used to explore patterns of population structure. •
  
  
  RESULTS
  We found strong differentiation between high elevation western desert populations and lower elevation eastern populations of P. hallii, with a pronounced break in structure occurring in western Texas. In addition, we confirmed that there are high levels of morphological and genetic structure between previous recognized varieties (var. hallii and var. filipes) within this species. •
  
  
  CONCLUSIONS
  The results of this study suggest that patterns of population structure within P. hallii may be driven by climatic variation over space. Overall, this study lays the groundwork for future studies on the genetics of local adaptation and reproductive isolation in this system.
authors: Section of Integrative Biology, The University of Texas at Austin, 1 University Station C0930, Austin, TX 78712, USA. davidbryantlowry@gmail.com
authors: David B
authors: DB
authors: Lowry
authors: Colin T
authors: CT
authors: Purmal
authors: Thomas E
authors: TE
authors: Juenger
mesh_terms: D000483:Alleles; D002980:Climate; D056426:Genetic Loci / Q000235:genetics; D005828:Genetics, Population; D005843:Geography; D008897:Panicum / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development*; D010641:Phenotype; D011157:Population Dynamics; D025341:Principal Component Analysis; D019655:Quantitative Trait, Heritable; D013781:Texas