Fig. 1.

Evidence of a large nonrecombining region on Chr 12 in Pungitius pungitius. Points represent 100-kb windows. Data from confirmed or hypothesized sex chromosomes are shown as black points with a blue loess regression; data from all other chromosomes are in gray. Results for Chr 12 are shown for the three Pungitius species. Chr 19 for Gasterostreus aculeatus, which has a well-established SDR with known strata, is shown as a control. The three statistics are: F_ST between males and females, the percentage of SNPs with a minor allele frequency >0.1 in one sex and absent in the other, and the log₂ of the male:female ratio for nucleotide diversity (π). The vertical dashed lines for P. pungitius show the inversion breakpoints at 3.5 and 18.9 Mb identified by Natri (2015). Chromosome positions refer to the sex chromosome, and autosomes have been rescaled to the same length. Abbreviations following the latin binomials are used in later figures.