Genetic identification by mass spectrometric analysis of single-nucleotide polymorphisms: ternary encoding of genotypes.

An approach to genetic identification using biallelic single-nucleotide polymorphism (SNP) genetic markers is described in which the three possible genotypes, AA, Aa, or aa, where "A" and "a" represent the two SNP alleles, are assigned a ternary (base 3) digit of 0, 1, or 2, respectively. Genotyping an individual over a panel of separate SNP markers produces a composite ternary genetic code that can be converted to an easily stored, decimal (base 10) genetic identification number. The unambiguous identification of 11 individuals is demonstrated using ternary genetic codes generated from MALDI-TOF mass spectrometric genotyping data from 7 different SNP markers.