Summary of the linkage analysis of the congenic lines and dual color FISH mapping of BACs on chromosomes of fibroblasts from the congenic lines. (a) Linkage analysis using congenic lines results in refinement of the Skts1 locus on chromosome 7 to an interval of 0.9 cM. Each bar represents a different congenic line; the location of the bar indicates the region of chromosome 7 for which the congenics contain M. spretus alleles. The closed bars represent congenic lines that retained papilloma resistance, whereas the open bars represent congenics that did not show resistance. The MIT markers used for both genetic mapping and allelic imbalance analysis are indicated. The closed bar on the right shows the minimum region determined by allelic specific genetic changes. The physical location of the markers in Mb is based on data from Ensembl database (Version 40) (http://www.ensembl.org). (b, c) FISH analysis on metaphase chromosomes of fibroblasts from the congenic line 1230. Two differently labeled BACs (cy3 and FITC) were cohybridized. RPCI23-93H2 (mapped at 43.7 Mb, green) and RPCI23-5O6 (mapped at 56.2 Mb, red) are mapped in the same orientation in both NIH/Ola homozygous (NN) (b) and M. spretus homozygous (SS) (c) fibroblasts. The panels below b and c show higher magnification pictures of the metaphase spreads, and demonstrate that the BACs labelled in green and red are in the same orientation in both cell types with respect to the densely staining centromere region at the top of the chromosome.