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. 2021 Aug 24;10:e70990. doi: 10.7554/eLife.70990

Figure 8. A genetic map for Pristionchus pacificus based on recombination in inter-strain hybrids.

(A) Crossing scheme to generate a recombination map using three parental strains. California PS312 (CA), Washington PS1843 (WA), and La Réunion Island RSB001 (LR) strains were crossed to obtain F1 hybrids, which were then crossed to each other. Whole-genome sequencing of progeny from crosses between hybrid F1s enabled the analysis of meiotic recombination events in each F1 parent. (B) Genotype transitions along a chromosome in F2 correspond to recombination in the male or hermaphrodite F1 parent. (C) Marey plots show genetic map position in centimorgans vs. the physical position in megabases for male (green) and hermaphrodite (magenta) meiosis. Each bin was treated as a single locus and dots were plotted at the center of each marker bin. Map positions were computed with OneMap as described. The observed map length of ~50 cM indicates that chromosomes undergo an average of one crossover (CO) per meiosis. The X chromosome lacks a homolog in males, so there is no male-specific map for the X in our data. See also Figure 8—figure supplement 1 and Figure 8—source data 1.

Figure 8—source data 1. Genotype calls and maps distances plotted in Figure 8 and Figure 8—figure supplement 1.
elife-70990-fig8-data1.xlsx (869.2KB, xlsx)

Figure 8.

Figure 8—figure supplement 1. Identification of informative markers and genotyping of progeny from hybrid animals.

Figure 8—figure supplement 1.

(A) Genotyping. For each 100 kb genomic block, progeny were genotyped based on the number of California PS312 (CA), Washington PS1843 (WA), and La Réunion Island RSB001 (LR)-specific variants they contained, given the expectation of four possible genotypes CA/CA, CA/LR, WA/CA, WA/LR. In scatterplot, each point represents a single bin in a specific individual, with X = fWA + fLR - 2fCA, and Y = fLR fWA. Gray dots represent genotypes that are conservatively left as ‘not called.’ (B) Genotypes of the mapping panel. F2 genotypes inherited from male (left) and hermaphrodite (right) parents. Each thin row is one progeny. White vertical stripes represent 100 kb windows that could not be reliably genotyped due to low numbers of P0-specific variant sites and/or sequencing depth of progeny.