a. Sanger sequencing reveals heterozygosity for a novel variant -13909C>A in individuals 64 and 71. Individuals 11 and 82 are homozygous C/C for -13909, so the -13909C>A variant only explains the equal allelic expression in individuals 64 and 71.
b. -13910C>T and -13909C>A are on different haplotypes. DNA from individuals 64 and 71 was cloned and sequenced, showing that the -13909A allele is on the -13910C haplotype.