TAS2R38 (Taste 2 Receptor Member 38)

Overview

The TAS2R38 gene encodes a bitter taste receptor that determines the ability to taste bitter substances like PTC (phenylthiocarbamide) and PROP (6-n-propylthiouracil). This explains the distinction between Supertasters and Non-tasters.

📍 Position
7q34 (Chromosome 7)

🏷️ Category
Appearance

👅 Function
Bitter Taste Receptor

📊 Frequency
Non-taster ~25-30%

Function of the TAS2R38 Receptor

The TAS2R38 receptor binds specific bitter substances and triggers a bitter taste sensation. Three SNPs define the two main haplotypes with different levels of bitter sensitivity.

Key Functions:

🛡️ Toxin Detection

Bitter substances are often natural toxins. Tasters recognize these better and avoid potentially harmful substances.

🍽️ Dietary Preferences

Influences food choices. Tasters often prefer sweet flavors and avoid bitter vegetable varieties.

💡 Haplotypes: PAV (Proline-Alanine-Valine) = Taster vs. AVI (Alanine-Valine-Isoleucine) = Non-taster. Heterozygotes are medium tasters.

Health Significance

✅ Advantages

Better toxin detection due to increased bitter sensitivity
Healthier dietary choices (more vegetables, fewer processed foods)
Lower nicotine consumption (tasters smoke less often)

⚠️ Challenges

Restricted food selection
Aversion to bitter vegetables (broccoli, Brussels sprouts)
Impact on dietary habits

⚠️ Supertaster Effect: People with two PAV haplotypes often have more taste buds and taste bitterness extremely intensely—consequently, they tend to like sweet flavors less.

🧬 Genetic Variants

rs713598
7:141972810

Non-taster

C

/

Taster

G

A49P (145G>C)
G (Ala) is part of the PAV haplotype (taster), C (Pro) leads to bitter perception

Functional Allele:
~50-60%

rs1726866
7:141972804

C
Taster

→

T
Non-taster

A262V (785C>T)
T (Val) is part of the AVI haplotype (non-taster), defines bitter sensitivity

Non-taster Allele:
~40-50%

rs10246939
7:141972704

C
Taster

→

T
Non-taster

V296I (886C>T)
Together with the other SNPs, defines the PAV or AVI haplotype

Variant:
~45-55%

Frequency and Types

AVI/AVI (Non-taster)

~25-30%

PAV/PAV (Supertaster)

~20-30%

PAV/AVI (Medium Taster)

~40-55%

🧬 Genetics: The three haplotypes (PAV, AVI) are combined by three SNPs. Supertasters often have more fungiform papillae and taste bitterness more intensely.

📚 Data Sources

OMIM: #607751 (Taste Receptor, Type 2, Member 38)
dbSNP: rs713598, rs1726866, rs10246939
PubMed: Kim et al. (2003) – Positional cloning of the human quantitative trait locus underlying taste sensitivity to phenylthiocarbamide
Science: Genetics of taste perception
Genetics Home Reference: TAS2R38

Last Update: February 2026

Testing and Practical Significance

A genetic test can reveal your genetic predisposition for bitter taste:

🧪 Genetic Test Results
PAV/PAV: Supertaster – extremely sensitive to bitterness
                        
PAV/AVI: Medium taster – normal sensitivity
                        
AVI/AVI: Non-taster – minimal bitter perception

🍽️ Practical Application: This information helps with personalized nutrition plans and explains why some people find certain foods unpleasantly bitter.

TAS2R38