title: Association between the geographic distribution during the last glacial maximum of Asian wild rice, Oryza rufipogon (Poaceae), and its current genetic variation.
abstract: OBJECTIVE
  The combination of traditional population genetic studies and species distribution modeling (SDM) provides many new insights in detecting phylogeographic signals. In Asian wild rice (Oryza rufipogon), the progenitor of cultivated Asian rice, geographical subdivision has been documented in many genetic studies although the root cause of this subdivision remains unknown. Surprisingly, environmental factors associated with the spatial and temporal distribution of O. rufipogon have rarely been examined. The aim of this study is to understand the historical distribution of O. rufipogon and its relationship to the current geographical pattern of genetic variation.
  
  
  METHODS
  We used SDM to examine the present, past, and future distribution of O. rufipogon. The estimated distribution during the Last Glacial Maximum was then compared with genetic data from our previous work.
  
  
  RESULTS
  The predicted paleodistribution of O. rufipogon at the Last Glacial Maximum was separated into disconnected east and west ranges. This past distribution is consistent with the current geographic pattern of genetic variation, with two genetic groups that intergrade. Annual precipitation is the single factor that contributes most to SDM estimates. SDM predictions for 2080 indicate a general trend of increasing probability of presence and range expansion.
  
  
  CONCLUSIONS
  (1) The historically disjunct distribution potentially contributes to the current genetic subdivision of O. rufipogon. (2) Water availability is an important factor that limits the distribution of O. rufipogon. (3) Global warming is a lesser threat than other human-mediated factors to the conservation of this endangered species.
authors.affiliation: Department of Biology Washington University, Campus Box 1137, 1 Brookings Dr., St. Louis, Missouri 63130, USA. puhuang@wustl.edu
authors.forename: Pu
authors.initials: P
authors.lastname: Huang
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Schaal
mesh_terms: D001208:Asia; D002980:Climate; D017753:Ecosystem; D014644:Genetic Variation; D005843:Geography; D057232:Global Warming; D006802:Human Activities; D006801:Humans; D046448:Ice Cover; D058974:Phylogeography / Q000639:trends; D006109:Poaceae / Q000235:genetics* / Q000254:growth & development; D013997:Time Factors; D014867:Water / Q000378:metabolism
chemical_list: D014867:Water