ARI chromosome 15. Chromosome 15 in 22 genotyped ARI strains and the 34 BXD RI strains. Dark grey regions are homozygous B6, white regionsare homozygous DBA, and light grey regions are heterozygous. All BXD data are taken from  and are publicly accessible via http://www.nervenet.org/papers/bxn.html. Number of recombinations per strain is displayed below each strain. Where heterozygous regions were present, the number of recombinations was calculated based on the smallest number of recombinations that might ultimately be resolved from that pattern. For example BXD47 has 0 recombinations rather than 2. Even discounting additional recombinations from resolution of heterozygous regions, the ARI animals have a considerably larger number of recombinations, 3.0 per strain compared to 1.3 per strain in BXD animals for Chr 15. BXD37, BXD41, BXD47, and BXD58, are now extinct.