Fig. 1: Geographic origin and phylogenetic clustering of analysed samples.
From: Different sex determination systems in two closely related Eurasian minnow (Phoxinus) species
a Geographic distribution of P. csikii (orange) and P. phoxinus (green). Sampling drainages are numbered as follows: (1) Middle-Lower Rhine boundary, (2) Meuse, (3) Neckar, 4, (5) Danube. Specific location details can be found in Supplementary Table S1. The to-date known hybrid contact zone is indicated by diagonal stripes. b Maximum likelihood phylogeny of P. csikii (orange) and P. phoxinus (green) based on 12 concatenated mitochondrial protein-coding gene sequences, with Pimephales promelas as an outgroup. Branch lengths are log-transformed. Bootstrap support values ≥ 70% are shown in blue at key nodes, and the longest 5% of branches are labelled with their log-transformed lengths in grey.
