title: Intraspecific lineage divergence and its association with reproductive trait change during species range expansion in central Eurasian wild wheat Aegilops tauschii Coss. (Poaceae).
abstract: BACKGROUND
  How species ranges form in landscapes is a matter of long-standing evolutionary interest. However, little is known about how natural phenotypic variations of ecologically important traits contribute to species range expansion. In this study, we examined the phylogeographic patterns of phenotypic changes in life history (seed production) and phenological (flowering time) traits during the range expansion of Aegilops tauschii Coss. from the Transcaucasus and Middle East to central Asia.
  
  
  RESULTS
  Our comparative analyses of the patterns of natural variations for those traits and their association with the intraspecific lineage structure showed that (1) the eastward expansion to Asia was driven by an intraspecific sublineage (named TauL1b), (2) high seed production ability likely had an important role at the initial dispersal stage of TauL1b's expansion to Asia, and (3) the phenological change to early flowering phenotypes was one of the key adaptation events for TauL1b to further expand its range in Asia.
  
  
  CONCLUSIONS
  This study provides for the first time a broad picture of the process of Ae. tauschii's eastward range expansion in which life history and phenological traits may have had respective roles in its dispersal and adaptation in Asia. The clear association of seed production and flowering time patterns with the intraspecific lineage divergence found in this study invites further genetic research to bring the mechanistic understanding of the changes in these key functional traits during range expansion within reach.
authors.affiliation: Fukui Prefectural University, Matsuoka, Eiheiji, Yoshida, Fukui, Japan. matsuoka@fpu.ac.jp.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Matsuoka
authors.affiliation: Laboratory of Plant Genetics, Graduate School of Agricultural Science, Kobe University, Nada-ku, Kobe, Japan. takumi@kobe-u.ac.jp.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Takumi
authors.affiliation: Laboratory of Crop Evolution, Plant Germ-plasm Institute, Graduate School of Agriculture, Kyoto University, Mozume, Muko, Kyoto, Japan. kawahara.taihachi.2z@kyoto-u.ac.jp.
authors.forename: Taihachi
authors.initials: T
authors.lastname: Kawahara
mesh_terms: D001208:Asia; D035264:Flowers / Q000502:physiology; D014644:Genetic Variation; D006109:Poaceae / Q000145:classification* / Q000235:genetics* / Q000502:physiology; D012098:Reproduction; D012639:Seeds / Q000502:physiology