Patterns of Polymorphism and Demographic History in Natural Populations of Arabidopsis lyrata

Jeffrey Ross-Ibarra, Stephen I. Wright, John Paul Foxe, Akira Kawabe, Leah DeRose-Wilson, Gesseca Gos, Deborah Charlesworth, Brandon S. Gaut

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Many of the processes affecting genetic diversity act on local populations. However, studies of plant nucleotide diversity have largely ignored local sampling, making it difficult to infer the demographic history of populations and to assess the importance of local adaptation. Arabidopsis lyrata, a self-incompatible, perennial species with a circumpolar distribution, is an excellent model system in which to study the roles of demographic history and local adaptation in patterning genetic variation.

Principal Findings: We studied nucleotide diversity in six natural populations of Arabidopsis lyrata, using 77 loci sampled from 140 chromosomes. The six populations were highly differentiated, with a median FST of 0.52, and STRUCTURE analysis revealed no evidence of admixed individuals. Average within-population diversity varied among populations, with the highest diversity found in a German population; this population harbors 3-fold higher levels of silent diversity than worldwide samples of A. thaliana. All A. lyrata populations also yielded positive values of Tajima's D. We estimated a demographic model for these populations, finding evidence of population divergence over the past 19,000 to 47,000 years involving non-equilibrium demographic events that reduced the effective size of most populations. Finally, we used the inferred demographic model to perform an initial test for local adaptation and identified several genes, including the flowering time gene FCA and a disease resistance locus, as candidates for local adaptation events.

Conclusions: Our results underscore the importance of population-specific, non-equilibrium demographic processes in patterning diversity within A. lyrata. Moreover, our extensive dataset provides an important resource for future molecular population genetic studies of local adaptation in A. lyrata.

Original languageEnglish
Article numbere2411
Pages (from-to)-
Number of pages13
JournalPLoS ONE
Volume3
Issue number6
DOIs
Publication statusPublished - 11 Jun 2008

Fingerprint

Dive into the research topics of 'Patterns of Polymorphism and Demographic History in Natural Populations of Arabidopsis lyrata'. Together they form a unique fingerprint.

Cite this