Genetic and physical characteristics of the chromosome 13 sequence. a, A comparison of physical and genetic distance along chromosome 13. Markers from the deCODE genetic map were localized in the sequence. Their locations in the genetic map are plotted on the y axis and locations in the sequence are on the x axis (the sequence starts at position 17,918,001 to allow for the chromosome short arm and centromere). The female genetic map is shown in orange, the male map in green and the sex average map in red. The loci shown mark the extent of the region of low gene density (D13S1269–D13S71), the recombination jungle (D13S1315–D13S1825) and the recombination desert (D13S1301–D13S233). b, Variation in features along the chromosome. The sequence was divided into 1-Mb non-overlapping sections, and each section was studied for the features shown. The data for each feature were normalized to set the largest figure at 100% and the lowest at 0%. For the repeat coverage, the interspecies sequence homologies (defined in the Methods), and the exon and gene coverage, the percentage of each 1-Mb window is calculated. The range of data points for each plot are as follows: % G+C content (33.5–52.4); % SINE coverage (3.5–25); % LINE coverage (9.2–31.4); % with homology to mouse (1.1–14.2); % with homology to rat (0.9–11.9); % with homology to Tetraodon (0–1.8); % with homology to zebrafish (0–3); % with homology to Fugu (0–1.9); % exon coverage (0–4.1); genes per Mb (0–38); % gene coverage (0–100); ncRNAs per Mb (0–6); pseudogenes per Mb (0–24).