Fig. 1.

The genome-wide landscape and intraspecific variations of RH in maize. (a) Genome-wide distribution of RH across populations. The 6 populations in which RH hotspots were identified are illustrated, and the 7 RH hotspots are highlighted with red bars. The blue lines indicate the number of RH intervals (RHN), and the green lines indicate the RH rate (RHR). The purple rectangles indicate the approximate position of the centromere for each chromosome, and the recombination rate (RR) is shown as a heatmap bar below each population. (b) Comparisons of heterozygosity levels between the pericentromere and the remaining chromosome arms across 12 populations. “All Lines_1” indicates that all polymorphic markers were used to perform the comparison by joining all lines in 12 populations, while “All Lines_2” indicates that only the randomly selected 1100 markers from “All Lines_1” were employed to evaluate the impact of marker density on the comparison. The populations marked with a solid line and asterisk show a significantly higher heterozygosity level in the pericentromere than in the remaining chromosome arms, while the populations marked with a dotted line and asterisk show a significantly lower level of heterozygosity in the pericentromere than in the remaining chromosome arms. (c) The correlation between the heterozygosity ratio and the proportion of polymorphic markers in the two parents for 12 populations. The heterozygosity ratio is defined as the level of heterozygosity in the pericentromere divided by that in the remaining chromosome arms