@article{fdi:010053811,
  title = {{M}olecular adaptation in flowering and symbiotic recognition pathways : insights from patterns of polymorphism in the legume {M}edicago truncatula},
  author = {{D}e {M}ita, {S}t{\'e}phane and {C}hantret, {N}. and {L}oridon, {K}. and {R}onfort, {J}. and {B}ataillon, {T}.},
  editor = {},
  language = {{ENG}},
  abstract = {{B}ackground: {W}e studied patterns of molecular adaptation in the wild {M}editerranean legume {M}edicago truncatula. {W}e focused on two phenotypic traits that are not functionally linked: flowering time and perception of symbiotic microbes. {P}henology is an important fitness component, especially for annual plants, and many instances of molecular adaptation have been reported for genes involved in flowering pathways. {W}hile perception of symbiotic microbes is also integral to adaptation in many plant species, very few reports of molecular adaptation exist for symbiotic genes. {H}ere we used data from 57 individuals and 53 gene fragments to quantify the overall strength of both positive and purifying selection in {M}. truncatula and asked if footprints of positive selection can be detected at key genes of rhizobia recognition pathways. {R}esults: {W}e examined nucleotide variation among 57 accessions from natural populations in 53 gene fragments: 5 genes involved in nitrogen-fixing bacteria recognition, 11 genes involved in flowering, and 37 genes used as control loci. {W}e detected 1757 polymorphic sites yielding an average nucleotide diversity (pi) of 0.003 per site. {N}on-synonymous variation is under sizable purifying selection with 90% of amino-acid changing mutations being strongly selected against. {A}ccessions were structured in two groups consistent with geographical origins. {E}ach of these two groups harboured an excess of rare alleles, relative to expectations of a constant-sized population, suggesting recent population expansion. {U}sing coalescent simulations and an approximate {B}ayesian computation framework we detected several instances of genes departing from selective neutrality within each group and showed that the polymorphism of two nodulation and four flowering genes has probably been shaped by recent positive selection. {C}onclusion: {W}e quantify the intensity of purifying selection in the {M}. truncatula genome and show that putative footprints of natural selection can be detected at different time scales in both flowering and symbiotic pathways.},
  keywords = {},
  booktitle = {},
  journal = {{B}mc {E}volutionary {B}iology},
  volume = {11},
  numero = {},
  pages = {229},
  ISSN = {1471-2148},
  year = {2011},
  DOI = {10.1186/1471-2148-11-229},
  URL = {https://www.documentation.ird.fr/hor/fdi:010053811},
}