ABSTRACT: The 112kb congenic was identified via routine monitoring of the proximal and distal SNP sites of the heterozygous Line 4a C57Bl/6J (B6J)-DBA/2J (D2J) congenic offspring (PMID: 26658939). The 112kb congenic was identified via routine monitoring of the proximal and distal SNP sites of the heterozygous Line 4a C57Bl/6J (B6)-DBA/2J (D2) congenic offspring (Yazdani et al. 2015). Like the Line4a congenic, the original mouse of interest possessed a D2J SNP site at the proximal end of the D2J interval (rs29383600; mm9 - chr11:50,186,508, mm10 - chr11:50,373,006). To identify the distal D2J boundary of this new congenic, we generated a list of known SNPs within a roughly 55kb interval spanning downstream from the distal end of the originally characterized 206kb “critical interval” harboring Hnrnph1 and Rufy1 (mm9 - chr11:50,295,887-50,352,284, mm10 - chr11:50,482,385-50,538,782). Starting from the upstream portion of the interval, PCR primers were designed to every five SNPs, and 200bp region around each SNP was amplified, run on a 1.5% agarose gel, visualized for band specificity. Single appropriately-sized bands were then excised and gel purified (Promega Wizard SV Gel and PCR Clean-Up System, Cat A9281), and prepared for sanger sequencing (Genewiz). Using the SNP data from the Mouse Genome Project (Sanger Institute) for reference, the sequenced SNPs were deemed as either heterozygous for B6J and D2J SNPs or homozygous/wildtype B6J. The final SNP we identified as D2 was rs29459915 (mm9 - chr11:50,297,762, mm10 - chr11:50,484,260), and the first SNP we identified as B6 was rs254771403 (mm9 - chr11:50,300,250, mm10 - chr11: 50,486,748).
