Figure 4

Geographic distribution, mtDNA haplotype distribution, and autosomal AFLP based admixture proportions of great black-backed gull (L. marinus) populations. The breeding range (black), and sampling locations (red dots) of marinus. For each of the eight colonies a boxed area contains individuals that we used for the analyses of 230 AFLP loci and HVR1 and cytB mtDNA sequencing. Colony name abbreviations above the top-left corner of each box correspond with those in Table 1. Genotypes were analysed by STRUCTURE and revealed the presence of four distinct ancestral populations among present day marinus. In this figure these are represented by four different colours (pale red, pale blue, pale green, and pale orange). Each individual is represented by a single (multi) coloured bar, on top of which there is either a black filled square (indicating that this individual displayed an mtDNA clade 1 haplotype), or a white square (representing clade 2 mtDNA haplotypes). The proportion of each colour within a single bar indicates the relative contribution of one of these four ancestral populations to the genome of that gull. For instance, the top left panel represents 18 marinus from a Nearctic population (ONT). Of these, 11 displayed a clade 1 mtDNA haplotype (black squares above the coloured bars), whereas seven displayed a clade 2 mtDNA haplotype (white squares). Among the 18 birds, the leftmost five display a 100% fixed autosomal contribution of the ancestral population coded by pale red to their genomes. The rightmost nine individuals show 100% fixed contribution of another (pale green) ancestral population. There are also four individuals with various degrees of admixed contributions of two or more ancestral populations.