Fig. 1

Recombination supression in the hybrids between C. briggsae and C. nigoni. A Schematic diagram showing the crossing strategies to generate introgression from the GFP-labeled C. briggsae genome (Cbr, blue bars) to the C. nigoni genome (Cni, orange bars) as a marker. Chromosome numbers are indicated. B Comparison of introgression fragment sizes between Caenorhabditis (this study) and Drosophila hybrids [10]. C Density plot showing the distribution of introgression size of 112 independently generated C. nigoni strains that each carries a C. briggsae introgression fragment. The median size of the introgression fragments is indicated by a red dashed line. D Box plots showing the individual introgression sizes of the 112 lines across chromosomes (differentially color-coded). The mean of introgression size for each chromosome is indicated on the top. Note that introgression fragments from the C. briggsae chromosome IV demonstrate the largest mean and median size (p < 0.05, Wilcoxon rank sum test with multiple testing correction using FDR method)