Fine genetic mapping of Lgn1. (A) Sequence chromatograms of PCR products amplified with D13Die30.2 from genomic DNA of A/J, C57BL/6J, and selected backcross animals. Extensive sequencing of D13Die30.2 PCR products from A/J and C57BL/6J genomic DNA (see Methods) detected a single nucleotide polymorphism at position 51 in the 1479 bp corresponding to D13Die30 (A/J, A; C57BL/6J, G). D13Die30.2 PCR products from 10 backcross animals were sequenced with D13Die30-F and Die30-seq3. These animals include two A/J-like controls (211, 686), three heterozygous controls (150, 176, and 204) and five animals previously identified as recombinants within the Naiparray (226, 771, 541, 549, and 661). Partial sequence tracings using primer D13Die30-F spanning the SNP at position 51 in D13Die30 from selected animals are shown. Heterozygous animals 226, 771, and 549 have two equivalent peaks at this position. (B) Polymorphic markers spanning the Naip array were assayed on genomic DNA from 10 animals in our Lgn1 cross (see Methods). Marker positions are indicated as ordered in the C57BL/6J haplotype (Fig. 6). Black squares indicate heterozygous loci, open circles indicate A/J-like homozygous loci. Three recombination events (541, 661, and 549) were mapped between D13Die26 and D13Die37, located within Naip2. Two recombination events (226 and 771) were mapped between D13Die30 and D13Die36-A, located within ΔNaip. The genetic interval forLgn1, including the 5′ portion of Naip2, all ofNaip5, and the 3′ portion of ΔNaip are indicated. The Lgn1 phenotype is indicated at the bottom (C57BL/6J nonpermissive; A/J permissive).
