Bitter taste has evolved in mammals as a crucial, important warning signal against ingestion of poisonous or toxic compounds. However, many beneficial compounds are also bitter, and taste masking of bitter tasting pharmaceutical compounds is a billion dollar industry. The diversity of compounds that elicit bitter-taste sensations is very large and more than two dozen members of the T2R bitter taste receptor family have been identified. Individuals are now known to be genetically predisposed to respond or not to respond to the bitter taste of a number of substances. For example, large individual differences in the perception of bitterness have been well documented in compounds as different as nicotine, thiocyanates such as those found in cruciferous vegetables, and many bitter beta-glucopyranosides. This may have broad implications for nutritional status and tobacco use and common allelic variants of a member of the T2R bitter taste receptor gene family have been shown to underlie variation in the ability to taste phenylthiocarbamide (PTC) [Science (2003) 299, 1221-1225; HHS Ref No: E-169-2001/0].
Scientists at the NIDCD have extended these results to other bitter taste receptors and have sequenced 22 of the 24 known T2R genes in a series of populations worldwide, including Northern Europeans, Hungarians, Japanese, Cameroonians, Pygmies and South American Indians and the present invention includes these isolated sequences and their variants. This includes a total of 127 SNPs and 103 different protein coding haplotypes, including those defined for the PTC Receptor (T2R38) [E-169-2001/0]. The inventors showed that 77% of the SNPs identified caused an amino acid substitution in the encoded receptor protein, giving rise to a very high degree of receptor protein variation in the population (Kim et al. (2005) Human Mutation 26, 199-204). The frequencies of these different haplotypes have been shown to differ in different populations which will aid in population-specific studies, such as those targeting differences in taste perception between Europeans and Asians, for example.
The invention available for licensing includes these novel SNPs and haplotypes and methods of use, which can be used to better identify and characterize different groups of individuals within and between populations that vary in the their bitter taste abilities. This is important to the food and flavoring industry, for example, where these variants can be used to aid in the development of a variety of taste improvements in foods and orally administered medications.