TAS2R38 rs4713917: Bitter Taste Genetics Explained
The genetic variant rs4713917 is an intron variant located within the bitter taste receptor gene TAS2R38 on chromosome 7. It is part of the well-characterized linkage group associated with the classic PAV and AVI haplotypes that dictate human sensitivity to bitter compounds such as phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP). Individuals carrying alleles linked to the active receptor form typically perceive certain vegetables and thiourea-containing compounds as notably more bitter than non-tasters.
What each genotype means
Reduced bitter taste sensitivity
You carry two copies of the non-tasting A allele at rs4713917, which tracks closely with the non-functional AVI form of the TAS2R38 receptor. Individuals with this genotype generally experience significantly less bitterness when tasting glucosinolate-containing cruciferous vegetables (such as broccoli and kale) or phenylthiocarbamide. However, dietary associations vary across ancestral backgrounds, and this genotype does not cause or diagnose any medical disease.
Carried by approximately 18% to 25% of individuals worldwide, with higher frequencies observed in European cohorts and slightly lower rates in East Asian populations.
Intermediate bitter perception
You carry one taster allele and one non-taster allele at rs4713917, typically corresponding to the intermediate AVI/PAV diplotype. People with this genotype generally perceive moderate levels of bitterness from compounds found in brassica vegetables, falling between non-tasters and sensitive tasters. Because bitterness perception is shaped by both environmental habits and other minor taste receptor alleles, individual sensitivity can vary.
Carried by approximately 45% to 50% of people globally, representing the most common genotype across most worldwide populations due to balanced heterozygosity.
Enhanced bitter taste sensitivity
You carry two copies of the tasting G allele at rs4713917, which tracks with the fully functional PAV haplotype of the TAS2R38 receptor. Research indicates that individuals with this genotype often perceive phenylthiocarbamide, propylthiouracil, and natural brassica glucosinolates as noticeably bitter. Some studies suggest this heightened sensitivity may influence food selection and vegetable intake, although findings differ depending on cultural and ancestral dietary contexts.
Carried by roughly 25% to 35% of people globally, being particularly prevalent in certain East Asian populations and moderately common across African and European groups.
Genetic Location and Variant Details
The single nucleotide polymorphism rs4713917 is located on chromosome 7 within the genomic region encompassing the TAS2R38 gene. As documented in databases like dbSNP, this variant is situated in non-coding intronic sequence and represents a single-base transition. While it does not directly alter an amino acid residue on its own, it exists in exceptionally tight linkage disequilibrium with three classic missense variants in the TAS2R38 coding sequence: rs713598 (Ala49Pro), rs1726866 (Val262Ala), and rs10246939 (Ile296Val). Because these adjacent polymorphisms are inherited together across generations as cohesive blocks known as haplotypes, rs4713917 serves as an effective genetic surrogate for tracking bitter taste perception phenotypes.
Biological Role of the TAS2R38 Receptor
The TAS2R38 gene encodes a member of the taste 2 receptor family, a class of seven-transmembrane G protein-coupled receptors expressed primarily on the apical surface of taste receptor cells in tongue papillae. The TAS2R38 receptor specifically recognizes compounds containing a thiocyanate or thiourea moiety (-N-C=S), including glucosinolates naturally occurring in cruciferous plants such as kale, broccoli, Brussels sprouts, and watercress. When an activating ligand binds the receptor, intracellular signaling cascades release gustducin and trigger sensory impulses to the central nervous system, producing the sensation of bitterness. Evolutionary biologists theorize that this receptor evolved to deter mammals from consuming potentially toxic botanical compounds and goitrogens found in wild vegetation.
Phenotypic Associations and Evidence Strength
Decades of sensory evaluation and association studies demonstrate robust, bimodal differences in human bitter taste sensitivity tied to the TAS2R38 locus. The functional receptor form is characterized by the PAV haplotype (proline-alanine-valine at amino acid positions 49, 262, and 296), which confers strong sensitivity to bitter chemicals like PROP and PTC. Conversely, the nonfunctional AVI haplotype yields a receptor largely unresponsive to these compounds. Although the association between TAS2R38 genotype and perceived bitterness in laboratory tests is definitive, evidence directly connecting these genetic differences to everyday dietary habits or overall health outcomes is more limited and nuanced. Real-world food choices depend on preparation methods, sugar or salt additions, and learned cultural preferences.
Population Distribution and Evolutionary Balance
Variants across the TAS2R38 locus exhibit high heterozygosity worldwide, with major alleles maintaining balanced frequencies near 45% to 50% across most global populations. In non-African populations, the PAV and AVI combinations account for the vast majority of observed haplotypes, resulting in significant proportions of homozygous tasters, heterozygous intermediate tasters, and homozygous non-tasters. In populations of African ancestry, additional recombinant haplotypes—such as AAI and AAV—occur more frequently, generating broader phenotypic variation in sensory thresholds. Anthropologists suggest that balancing selection has preserved both taster and non-taster alleles across human history, possibly offering distinct protective advantages against plant toxins without completely restricting dietary variety.
Interpreting Results in Daily Life
Discovering your genotype at TAS2R38 markers like rs4713917 provides an interesting perspective on individual taste preferences, but it is not a medical diagnosis or clinical risk factor. Genetic testing cannot dictate which foods you must eat or avoid, as human culinary enjoyment is remarkably adaptable. Tasters who find cruciferous vegetables unpleasantly pungent or astringent often benefit from culinary adjustments like roasting, caramelizing, or combining greens with healthy fats and acidic dressings to suppress bitterness. Furthermore, this locus has no established role in guiding drug therapies; individuals should always consult healthcare providers or pharmacists regarding medical treatments and nutrition planning.
How common is this variant?
The variant rs4713917 maintains high heterozygosity across diverse global populations, with the minor and major alleles each circulating at approximately 45% to 50% frequency.
Frequently asked questions
Does TAS2R38 rs4713917 make me hate vegetables?
Not necessarily. While this genetic marker is linked to higher sensitivity to bitter compounds like glucosinolates, cooking methods, seasoning, and personal habits strongly influence vegetable intake.
What is the PAV versus AVI haplotype in TAS2R38?
PAV and AVI designate the amino acid sequences at positions 49, 262, and 296 of the TAS2R38 receptor. PAV creates a functional receptor that detects bitter thiourea compounds, whereas AVI produces an inactive receptor variant.
Can my bitter taste sensitivity change as I get older?
Yes. Although your underlying TAS2R38 genotype remains unchanged throughout life, taste receptor density and sensory acuity often decline naturally with age or environmental exposures.
Does this genetic variant affect medication choices?
No, rs4713917 does not have recognized clinical validity for altering pharmacological dosing or medication selection. Medication adjustments should always be discussed with a doctor or pharmacist.
Sources & further reading
Educational information only, last refreshed 9/13/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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A functional variant in the TAS2R38 gene that, as part of a three-SNP haplotype, determines the ability to taste bitter compounds like PTC.
Val262Ala substitution in TAS2R38 forming the middle polymorphic site of the classic AVI/PAV taste sensitivity haplotype.
One of the three classical missense variants defining the PAV bitter taster haplotype for phenylthiocarbamide and cruciferous vegetables.
Key missense polymorphism contributing to phenylthiocarbamide (PTC) and propylthiouracil (PROP) bitter taste taster status.
Functional marker affecting bitter taste perception of phenylthiocarbamide (PTC).
A key SNP in the TAS2R38 gene (part of the PAV/AVI haplotype) determining sensitivity to bitter compounds like PTC and PROP.