TAS2R38 rs1078747: Understanding Your Bitter Taste Genetics
The rs1078747 variant is a key genetic marker within the TAS2R38 gene that helps determine how intensely you perceive bitter tastes. It is one of three primary single-nucleotide polymorphisms that define whether an individual is a 'taster' or 'non-taster' of specific bitter compounds.
What each genotype means
Reduced bitter taste sensitivity
This genotype is associated with the AVI haplotype, which results in reduced sensitivity to bitter compounds like PTC and PROP. Research suggests individuals with this profile may perceive these substances as less intense compared to those with the PAV haplotype.
This genotype is common globally, appearing in a significant portion of diverse human populations as part of a balanced polymorphism.
Intermediate bitter taste sensitivity
Carrying one copy of each allele typically results in an intermediate level of bitter taste perception. You may find that your sensitivity to bitter compounds falls between the extremes of non-tasters and supertasters.
Heterozygous genotypes are frequently observed and often represent the most prevalent genotype category in many studied populations.
Increased bitter taste sensitivity
This genotype is associated with the PAV haplotype, often referred to as the 'supertaster' variant for PTC/PROP bitterness. Research indicates that individuals with this profile generally exhibit higher sensitivity to bitter stimuli and may have different dietary preferences or metabolic responses related to bitter taste receptor activation.
This genotype is found at high frequencies across many populations, contributing to the nearly balanced distribution of this trait worldwide.
What is rs1078747 and Where is it Located?
The rs1078747 variant is a single-nucleotide polymorphism (SNP) located within the TAS2R38 gene. This gene provides instructions for making a protein that functions as a bitter taste receptor on the surface of taste bud cells. The rs1078747 SNP is specifically responsible for one of the three amino acid substitutions that distinguish the two most common functional versions, or haplotypes, of this receptor: the PAV (proline-alanine-valine) haplotype and the AVI (alanine-valine-isoleucine) haplotype. Because these SNPs are inherited together as a block, rs1078747 serves as a critical indicator of which version of the receptor your body produces. By altering the structure of the receptor protein, this variant changes how effectively the receptor can bind to and detect certain bitter-tasting chemicals found in food and other substances.
The Role of the TAS2R38 Gene
The TAS2R38 gene encodes a G protein-coupled receptor that is specialized for detecting bitter compounds. This receptor is particularly famous for its role in sensing phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP), chemicals that are chemically similar to bitter compounds found in some vegetables like broccoli and Brussels sprouts. The PAV haplotype is associated with a functional receptor that allows individuals to perceive these substances as intensely bitter. In contrast, the AVI haplotype results in a receptor with significantly reduced sensitivity to these specific compounds. Because taste perception influences food preferences, the TAS2R38 gene is frequently studied in the context of dietary habits and nutritional choices. While it is a major factor in bitter taste sensitivity, it is important to note that other genetic and environmental factors also contribute to how we experience flavor.
Research Associations and Evidence Strength
The association between TAS2R38 variants and bitter taste perception is supported by moderate to strong evidence in scientific literature. Numerous studies have confirmed that individuals carrying the PAV haplotype (the 'taster' version) rate the intensity of PROP and PTC as significantly higher than those who are homozygous for the AVI haplotype (the 'non-taster' version). Beyond simple taste perception, researchers have investigated whether these genetic differences correlate with broader health outcomes, such as body mass index or preferences for specific vegetables. While some studies suggest links between TAS2R38 genotypes and obesity or metabolic health, these associations are complex and often influenced by a wide range of environmental and lifestyle variables. Consequently, while the link to bitter taste sensitivity is well-established, the clinical significance of this variant regarding long-term health outcomes remains an active area of research rather than a settled medical fact.
What You Can and Cannot Do With This Information
Understanding your TAS2R38 genotype can provide interesting insights into why you might find certain foods more bitter than others. If you carry the PAV haplotype, you may be more sensitive to the bitterness in cruciferous vegetables, which might explain personal food preferences. However, it is crucial to recognize that this information is not a diagnostic tool. You cannot use your genotype to predict your overall health, diagnose a medical condition, or determine your risk for specific diseases. Genetic variation is only one piece of a much larger puzzle that includes your upbringing, culture, and environment. If you have concerns about your diet, nutritional intake, or weight management, you should consult with a registered dietitian or a healthcare professional. They can provide personalized guidance based on your overall health profile rather than relying on a single genetic marker.
How common is this variant?
The TAS2R38 variant is a nearly balanced polymorphism, with the PAV and AVI haplotypes appearing at similar frequencies across many diverse human populations worldwide.
Frequently asked questions
What does it mean to be a 'supertaster'?
A supertaster is an individual who experiences taste, particularly bitterness, with greater intensity than the average person. While TAS2R38 variants contribute to this, it is not the only factor, as the density of taste buds on the tongue also plays a role.
Does my TAS2R38 genotype mean I will be a picky eater?
Not necessarily. While your genetics influence how you perceive bitterness, your food preferences are also shaped by your culture, family habits, and repeated exposure to different foods throughout your life.
Can I change my bitter taste sensitivity?
Your genetic sequence is fixed, but your perception of taste can be influenced by your environment. Repeated exposure to bitter foods can sometimes lead to increased tolerance or preference for those flavors over time.
Is this variant related to any medical conditions?
Research has explored potential links between TAS2R38 and various health outcomes, including obesity and metabolic health. However, these associations are complex and not strong enough to use this variant for medical diagnosis or risk prediction.
Sources & further reading
Educational information only, last refreshed 9/25/2026. 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.