Fig. 1

Maps of the distribution of WRR4 and RPM1 haplotypes in A. l. lyrata around the North American Great Lakes. Geographic distribution of 18 Arabidopsis lyrata ssp. lyrata sampling sites in the North American Great Lakes region showing variation in the dominant mating system at each site (based on previous estimates of outcrossing rates, T_m [28]) and the haplotype frequencies at two disease resistance loci (WRR4 and RPM1): a) mating system variation, with black circles indicating outcrossing populations (T_m > 0.6), grey circles indicating a mixed-mating population (0.4–0.6) and white circles indicating selfing populations (T_m < 0.4); b) piecharts showing the frequency of the 13 haplotypes for RPM1 (including a null allele); c) frequency of three RPM1 haplotypes containing major effect mutations: a premature stop codon mutation (black), a null genotype (blue) and a 9 bp deletion (grey); all other haplotypes for which no major effect mutation was detected (white) and d). piecharts showing the frequency in each population of the 29 haplotypes found for WRR4 (see Table 1 for sample sizes), with each colour indicating a different haplotype