Author Identifier (ORCID)
Abstract
Identification of the genomic regions that contribute to reproductive isolation and how they interact is a major goal of evolutionary genetics. Much effort has focused on locating candidate genes and potential barrier loci by scanning genomes for regions of excess differentiation (FST). An alternative, and perhaps more robust approach, is to scan for genomic regions exhibiting steep clines in allele frequency across a hybrid zone. We develop a computationally efficient method for approximating cline parameters for large number of loci, and apply it to genomic data from across a hybrid zone between flower colour varieties of Antirrhinum majus (A. m. m var. pseudomajus and A. m. m var. striatum). Most steep clines are clustered in seven genomic regions, only four of which were present from FST scans between all pair-wise comparisons. Six of these regions carry previously identified loci that influence flower colour in the hybrid zone. The seventh region harbours a novel locus, RUBIA, modifying magenta intensity. Clines at RUBIA approached fixation on the magenta side of the hybrid zone, whilst remaining polymorphic on the yellow side. This polymorphism on the yellow side may reflect a smaller phenotypic effect of RUBIA in yellow compared to magenta genetic backgrounds. Our findings illustrate how whole-genome cline scans in hybrid zones can robustly detect genomic regions contributing to phenotypic differences and highlight how different reproductive barrier loci interact across the genome.
Keywords
hybrid zones, reproductive isolation, genomic clines, antirrhinum majus, flower colour, barrier loci
Document Type
Journal Article
Date of Publication
7-1-2026
E-ISSN
15537404
Volume
22
Issue
7
PubMed ID
42441626
Publication Title
PLoS Genetics
Publisher
PLOS
School
School of Science
RAS ID
101963
Funding Information
This work was supported by the Biotechnology and Biological Sciences Research Council (https://www.ukri.org/councils/bbsrc/) (grants BB/S009256/1, BB/G009325/1, BBS/E/JI/230002C, and BBS/E/J/000PR9773 to EC, and Norwich Research Park Biosciences Doctoral Training Partnership grant (https://www.jic.ac.uk/training-careers/postgraduate-opportunities/nrp-doctoral-training-partnership/) (BB/M011216/1 to DR) and European Research Council (https://erc.europa.eu/homepage) ERC Advanced Grant HaplotypeStructure (101055327 to NB).
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
First Page
e1012173
Recommended Citation
Field, D. L., Stankowski, S., Reiter, T., Polechova, J., Bradley, D., Richardson, D. M., Whibley, A., Pal, A., Shipilina, D., Boell, L., Pickup, M., Xue, Y., Coen, E., & Barton, N. (2026). Genome-wide cline analysis identifies new locus contributing to a barrier to gene flow across an Antirrhinum hybrid zone. PLoS Genetics, 22(7), e1012173. https://doi.org/10.1371/journal.pgen.1012173