Fig 2. Map of selected Tpi SNPs that differ in strain-specificity including a list of the crosses that will produce heterozygotes at these sites and a description of the method to identify heterozygotes.

(A) DNA sequence of the segment of the fourth exon of the coding region containing three strain-specific sites (shaded) and two non-specific sites (underlined and bold). All SNPs are associated with a C or T (designated Y by IUPAC convention). Below are the types of crosses that can produce heterozygotes at e4₁₈₃ and e4₁₉₂. (B) Example of DNA sequencing chromatographs diagnostic of the two parental alleles as present as a hemizygote or homozygote, and the chromatograph representing the heterozygous combination that shows an overlap of the parental curves.