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Evidence for a large‐scale population structure among accessions of Arabidopsis thaliana : possible causes and consequences for the distribution of linkage disequilibrium
Author(s) -
OSTROWSKI MARIEFRANCE,
DAVID JACQUES,
SANTONI SYLVAIN,
MCKHANN HEATHER,
REBOUD XAVIER,
LE CORRE VALERIE,
CAMILLERI CHRISTINE,
BRUNEL DOMINIQUE,
BOUCHEZ DAVID,
FAURE BENOIT,
BATAILLON THOMAS
Publication year - 2006
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/j.1365-294x.2006.02865.x
Subject(s) - biology , linkage disequilibrium , microsatellite , genetics , genetic structure , evolutionary biology , population , disequilibrium , population genetics , single nucleotide polymorphism , allele , genetic variation , genotype , gene , medicine , demography , sociology , ophthalmology
The existence of a large‐scale population structure was investigated in Arabidopsis thaliana by studying patterns of polymorphism in a set of 71 European accessions. We used sequence polymorphism surveyed in 10 fragments of ∼600 nucleotides and a set of nine microsatellite markers. Population structure was investigated using a model‐based inference framework. Among the accessions studied, the presence of four groups was inferred using genetic data, without using prior information on the geographical origin of the accessions. Significant genetic isolation by geographical distance was detected at the group level, together with a geographical gradient in allelic richness across groups. These results are discussed with respect to the previously proposed scenario of postglacial colonization of Europe from putative glacial refugia. Finally, the contribution of the inferred structure to linkage disequilibrium among 171 pairs of essentially unlinked markers was also investigated. Linkage disequilibrium analysis revealed that significant associations detected in the whole sample were mainly due to genetic differentiation among the inferred groups. We discuss the implication of this finding for future association studies in A . thaliana .