Patterns of genetic diversity in outcrossing and selfing populations of Arabidopsis lyrata

Mable, B.K. and Adam, A. (2007) Patterns of genetic diversity in outcrossing and selfing populations of Arabidopsis lyrata. Molecular Ecology, 16, pp. 3565-3580. (doi: 10.1111/j.1365-294X.2007.03416.x) (PMID:17845431)

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Abstract

Arabidopsis lyrata is normally considered an obligately outcrossing species with a strong self-incompatibility system, but a shift in mating system towards inbreeding has been found in some North American populations (subspecies A. lyrata ssp. lyrata). This study provides a survey of the Great Lakes region of Canada to determine the extent of this mating system variation and how outcrossing rates are related to current population density, geographical distribution, and genetic diversity. Based on variation at microsatellite markers (progeny arrays to estimate multilocus outcrossing rates and population samples to estimate diversity measures) and controlled greenhouse pollinations, populations can be divided into two groups: (i) group A, consisting of individuals capable of setting selfed seed (including autogamous fruit set in the absence of pollinators), showing depressed outcrossing rates (T<sub>m</sub> = 0.2–0.6), heterozygosity (H<sub>O</sub> = 0.02–0.06) and genetic diversity (H<sub>E</sub> = 0.08–0.10); and (ii) group B, consisting of individuals that are predominantly self-incompatible (T<sub>m</sub> > 0.8), require pollinators for seeds set, and showing higher levels of heterozygosity (H<sub>O</sub> = 0.13–0.31) and diversity (H<sub>E</sub> = 0.19–0.410). Current population density is not related to the shift in mating system but does vary with latitude. Restricted gene flow among populations was evident among all but two populations (F<sub>ST</sub> = 0.11–0.8). Group A populations were more differentiated from one another (F<sub>ST</sub> = 0.78) than they were from group B populations (F<sub>ST</sub> = 0.59), with 41% of the variation partitioned within populations, 47% between populations, and 12% between groups. No significant relationship was found between genetic and geographical distance. Results are discussed in the context of possible postglacial expansion scenarios in relation to loss of self-incompatibility.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Mable, Professor Barbara
Authors: Mable, B.K., and Adam, A.
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:Molecular Ecology
ISSN:0962-1083

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
374091Genomes, pathogens and mate choice - implications for the evolution and maintenance of genetic diversityBarbara MableNatural Environment Research Council (NERC)NE/B50094X/1RI BIODIVERSITY ANIMAL HEALTH & COMPMED
419021Establishment of outcrossing rates in natural populations of Arabidopsis lyrataBarbara MableNatural Environment Research Council (NERC)NE/D006627/1RI BIODIVERSITY ANIMAL HEALTH & COMPMED