title: Genome size variation in wild and cultivated maize along altitudinal gradients.
abstract: It is still an open question as to whether genome size (GS) variation is shaped by natural selection. One approach to address this question is a population-level survey that assesses both the variation in GS and the relationship of GS to ecological variants. We assessed GS in Zea mays, a species that includes the cultivated crop, maize, and its closest wild relatives, the teosintes. We measured GS in five plants of each of 22 maize landraces and 21 teosinte populations from Mexico sampled from parallel altitudinal gradients. GS was significantly smaller in landraces than in teosintes, but the largest component of GS variation was among landraces and among populations. In maize, GS correlated negatively with altitude; more generally, the best GS predictors were linked to geography. By contrast, GS variation in teosintes was best explained by temperature and precipitation. Overall, our results further document the size flexibility of the Zea genome, but also point to a drastic shift in patterns of GS variation since domestication. We argue that such patterns may reflect the indirect action of selection on GS, through a multiplicity of phenotypes and life-history traits.
authors.affiliation: Department of Ecology and Evolutionary Biology, UC Irvine, Irvine, CA, 92697, USA.
authors.forename: Concepción M
authors.initials: CM
authors.lastname: Díez
authors.affiliation: Department of Ecology and Evolutionary Biology, UC Irvine, Irvine, CA, 92697, USA.
authors.forename: Brandon S
authors.initials: BS
authors.lastname: Gaut
authors.affiliation: Department of Mathematics, UC Irvine, Irvine, CA, 92607, USA.
authors.forename: Esteban
authors.initials: E
authors.lastname: Meca
authors.affiliation: Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, CP 04510, Mexico City, Mexico.
authors.forename: Enrique
authors.initials: E
authors.lastname: Scheinvar
authors.affiliation: Campo Experimental Bajío, Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, CP 38110, Celaya, Guanajuato, Mexico.
authors.forename: Salvador
authors.initials: S
authors.lastname: Montes-Hernandez
authors.affiliation: Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, CP 04510, Mexico City, Mexico.
authors.forename: Luis E
authors.initials: LE
authors.lastname: Eguiarte
authors.affiliation: CNRS, UMR de Génétique Végétale, INRA/CNRS/Univ Paris-Sud/AgroParisTech, Ferme du Moulon, Gif-sur-Yvette, France.
authors.forename: Maud I
authors.initials: MI
authors.lastname: Tenaillon
mesh_terms: D000531:Altitude; D002980:Climate; D018556:Crops, Agricultural; D003627:Data Interpretation, Statistical; D014644:Genetic Variation; D005828:Genetics, Population; D059646:Genome Size; D018745:Genome, Plant; D008800:Mexico; D012641:Selection, Genetic; D003313:Zea mays / Q000235:genetics*
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