Fig. 2: Contemporary hybridization among tropical eels.
From: Stable species boundaries despite ten million years of hybridization in tropical eels
a–d Genomic variation inferred in a PCA of all individuals of A. marmorata, A. megastoma, A. obscura, and A. interioris (Supplementary Fig. 5c), shown separately for four hybridizing species pairs: A. marmorata and A. megastoma (a), A. marmorata and A. obscura (b), A. megastoma and A. obscura (c), and A. marmorata and A. interioris (d). Individuals with intermediate positions are marked in gray with specimen IDs; species color code is as in Fig. 1. e Ancestry painting for 20 hybrids between A. marmorata and A. megastoma. The top and bottom horizontal bars represent 302 sites that are fixed for different alleles between the two species; all other bars indicate the alleles at each of those sites. White color indicates missing data. Heterozygous alleles are shown with the top half in each bar matching the second parental species and vice versa. f Ancestry painting for three contemporary hybrids between A. marmorata and A. obscura, based on 742 sites fixed between these two species. g Ancestry painting for one hybrid between A. megastoma and A. obscura, based on 525 fixed sites. h Ancestry painting for one hybrid between A. marmorata and A. interioris, based on 429 fixed sites. i Histogram of heterozygosity observed in hybrids. j Histogram of the proportions of hybrid genomes derived from the maternal species (according to mitochondrial sequence data). k Histogram of the relative morphological similarities between hybrids and the maternal species, measured as the relative proximity to the mean maternal phenotypes, compared to the proximity to the mean paternal phenotype. l Comparison of the proportions of hybrids’ genomes derived from the maternal species and the similarity to the mean maternal species’ phenotype. The dotted line indicates a significant positive correlation between the two measures (two-tailed t test; t = 3.1, p = 0.008, R2 = 0.381). PC, principal component; mito., mitochondrial genome; AD, distance between the dorsal fin and the anus; PDH, predorsal length without head; TL, total length.
