A paper from the collaboration between the Brodie lab at UVA and McGlothlin lab at VT was recently accepted at Heredity. The work led by grad students Kerry Gendreau (VT) and Mike Hague (UVA), reveals that the TTX-resistant NaV1.4 locus in garter snakes is on the Z-chromosome, explaining why genotype frequencies are so heterozygote-deficient.
Gendreau, KL, MTJ Hague, CR Feldman, ED Brodie Jr., ED Brodie III, JW McGlothlin. In Press. Sex linkage of the skeletal muscle sodium channel gene (SCN4A) explains apparent deviations from Hardy-Weinberg equilibrium of tetrodotoxin-resistance alleles in garter snakes (Thamnophis sirtalis). Heredity.