Distribution of variation by distance from centromere.

The height of each bar represents the number of SNPs detected in the 3 strains that are not close relatives of S288c (FL100, ∑1278b and SK1) in a 5 kb bin, starting at the centromere and moving up to 55 kb away in either direction, pooled across all chromosomes (that is, the first bin contains all SNPs within 0–5 kb of a centromere, the next bin contains all SNPs 5–10 kb from the centromere, and so on out to the last bin which contains all SNPs 55–60 kb from the centromere). The polymorphism rate is lower in the 25–30 kb closest to the centromere.