Restriction associated DNA-genotyping at multiple spatial scales in Arabidopsis lyrata reveals signatures of pathogen-mediated selection.

Buckley, J., Holub, E. B., Koch, M. A., Vergeer, P. and Mable, B. K. (2018) Restriction associated DNA-genotyping at multiple spatial scales in Arabidopsis lyrata reveals signatures of pathogen-mediated selection. BMC Genomics, 19(1), p. 496. (doi:10.1186/s12864-018-4806-7) (PMID:29945543) (PMCID:PMC6020377)

[img]
Preview
Text
166144.pdf - Published Version
Available under License Creative Commons Attribution.

2MB

Abstract

Genome scans based on outlier analyses have revolutionized detection of genes involved in adaptive processes, but reports of some forms of selection, such as balancing selection, are still limited. It is unclear whether high throughput genotyping approaches for identification of single nucleotide polymorphisms have sufficient power to detect modes of selection expected to result in reduced genetic differentiation among populations. In this study, we used Arabidopsis lyrata to investigate whether signatures of balancing selection can be detected based on genomic smoothing of Restriction Associated DNA sequencing (RAD-seq) data. We compared how different sampling approaches (both within and between subspecies) and different background levels of polymorphism (inbreeding or outcrossing populations) affected the ability to detect genomic regions showing key signatures of balancing selection, specifically elevated polymorphism, reduced differentiation and shifts towards intermediate allele frequencies. We then tested whether candidate genes associated with disease resistance (R-gene analogs) were detected more frequently in these regions compared to other regions of the genome. We found that genomic regions showing elevated polymorphism contained a significantly higher density of R-gene analogs predicted to be under pathogen-mediated selection than regions of non-elevated polymorphism, and that many of these also showed evidence for an intermediate site-frequency spectrum based on Tajima's D. However, we found few genomic regions that showed both elevated polymorphism and reduced FST among populations, despite strong background levels of genetic differentiation among populations. This suggests either insufficient power to detect the reduced population structure predicted for genes under balancing selection using sparsely distributed RAD markers, or that other forms of diversifying selection are more common for the R-gene analogs tested. Genome scans based on a small number of individuals sampled from a wide range of populations were sufficient to confirm the relative scarcity of signatures of balancing selection across the genome, but also identified new potential disease resistance candidates within genomic regions showing signatures of balancing selection that would be strong candidates for further sequencing efforts.

Item Type:Articles
Additional Information:This work was supported by a Natural Environment Research Council (NERC) project grant to BKM and EH (NE/H021183/1 and NE/H020691/1).
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Mable, Professor Barbara and Buckley, Dr James
Authors: Buckley, J., Holub, E. B., Koch, M. A., Vergeer, P., and Mable, B. K.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:BMC Genomics
Publisher:Biomed Central
ISSN:1471-2164
ISSN (Online):1471-2164
Copyright Holders:Copyright © 2018 The Authors
First Published:First published in BMC Genomics
Publisher Policy:Reproduced under a Creative Commons License

University Staff: Request a correction | Enlighten Editors: Update this record

Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
536551Assessing the impact of plant mating system and ploidy on adaptation to parasitism in changing environmentsBarbara MableNatural Environment Research Council (NERC)NE/H021183/1RI BIODIVERSITY ANIMAL HEALTH & COMPMED