Sequence similarity between B6-Chr1KM and WSB, PWK, and CAST Chr 1. (a) Distribution of the numbers of 100 kb blocks of the B6-Chr1KM Chr 1 with sequence similarities (%) to the corresponding blocks of the WSB, PWK, and CAST Chr 1. (b) Sliding window analysis of the similarities of Chr 1 sequences between B6-Chr1KM and WSB, CAST, or PWK. The B6-Chr1KM Chr 1 sequence was compared using 500 kb windows and 100 kb sliding intervals. The horizontal line indicates the level of 99.7% sequence similarity.