Identified herein are different forms of sweet and umami receptor encoding sequences that occur in different human populations. In particular, there are provided several single nucleotide polymorphisms (SNPs) that occur within the exons/coding sequence (and are therefore coding SNPs, cSNPs) of one of the three T1R genes. Some SNPs cause amino acid substitutions, while others introduce a chain termination codon, rendering a truncated product. Differences in these genes are believed to affect the sense of taste of individuals, such that individuals with different SNPs (or different haplotypes) are believed to perceive the taste of sweet or umami (e.g., glutamate) substances differently than the rest of the population. The ability to assay this allelic information is useful in the development of flavorings and flavor enhancers, as it can be used to define groups and populations who perceive tastes differently. This in turn allows the taste preferences of these groups to be addressed at the molecular level.