OR2M7 rs6754031: Genetics of Asparagus Odor Perception
The rs6754031 variant is a common single nucleotide polymorphism located within the olfactory receptor gene cluster on chromosome 1, close to OR2M7. Genetic studies link variations in this genomic locus to asparagus anosmia, which is the inability to smell sulfurous odorants produced in urine after eating asparagus. While this variant highlights the diversity of human sensory perception, having or lacking the ability to smell these metabolites has no known impact on physical health.
What each genotype means
Likely asparagus odor anosmia
Carrying two copies of the T allele is statistically associated with a reduced ability to smell the distinct sulfurous metabolites in urine after consuming asparagus. Evidence for this specific variant is limited and part of an olfactory receptor gene cluster where sensory perception varies widely. This genotype reflects a benign sensory trait and does not carry any medical or health implications.
Carried by approximately 30% to 40% of individuals in European populations, with variable frequencies across other ancestral groups.
Intermediate odor detection
Carrying one copy of the G allele and one copy of the T allele is associated with an intermediate likelihood of detecting asparagus-related odorants in urine. Because olfactory receptor genes exhibit complex linkage and subtle differences in receptor sensitivity, perception can vary considerably even among individuals with this genotype. This represents a normal variation in sensory perception and has no clinical consequences.
Carried by roughly 45% to 50% of individuals in populations of European ancestry.
Likely asparagus odor smeller
Individuals with two copies of the G allele are more likely to perceive the pungent sulfurous metabolites excreted after eating asparagus. Current published evidence linking this specific marker to asparagus anosmia is limited, and olfactory acuity also depends on multiple neighboring genes in the olfactory receptor cluster. This variation represents a harmless sensory difference rather than a health condition.
Carried by approximately 15% to 25% of individuals of European ancestry; frequency differs across other global ancestries.
What is rs6754031 and Where Is It Located?
The single nucleotide polymorphism rs6754031 is located on chromosome 1 in the region 1q44. This specific genomic neighbourhood contains a dense cluster of olfactory receptor family 2 genes, which are responsible for detecting various airborne chemical compounds. The variant represents a single base-pair change, commonly involving cytosine (C) and thymine (T) alleles. Rather than creating a pathological alteration, rs6754031 sits near or within the regulatory and coding architecture of odorant receptors like OR2M7. Genetic variants across this chromosome 1 cluster tend to be inherited together in tight linkage blocks, meaning rs6754031 often acts as a genomic tag reflecting broader variations that influence how certain chemical odorants bind to nasal receptors.
The Role of OR2M7 and Olfactory Receptors
The OR2M7 gene encodes an olfactory receptor, a specialized class of seven-transmembrane G protein-coupled receptors expressed on the surface of olfactory sensory neurons in the nasal epithelium. When chemical odorants enter the nasal passages, they interact with specific binding pockets on these receptors, triggering an intracellular signaling cascade that communicates with the olfactory bulb in the brain. Because each olfactory receptor is tuned to recognise distinct chemical structures, slight alterations in the amino acid sequence or expression levels can change how an individual perceives smells. In the case of OR2M7, researchers believe it plays an important role in recognizing volatile sulfur compounds, such as methanethiol and S-methyl thioesters, which are byproduct metabolites excreted following asparagus digestion.
Scientific Research and Asparagus Anosmia
The phenomenon of asparagus anosmia—the inability to detect the distinctive, pungent odor of post-asparagus urine—has been the subject of several large-scale genome-wide association studies (GWAS). Research examining thousands of participants discovered that variations across the chromosome 1 olfactory cluster strongly correlate with whether an individual can smell these urine metabolites. Studies in cohorts of European ancestry have repeatedly pointed to the OR2M7 region, noting significant statistical signals for markers like rs6754031, rs4481887, and rs6689553. However, scientists classify the overall clinical evidence strength as limited for direct functional consequence, because the trait is complex: it involves both individual differences in olfactory perception (smelling the compounds) and differences in metabolic production (excreting the compounds).
Population Frequency and Ancestry Patterns
Genetic variation in the OR2M7 olfactory cluster is widespread throughout human populations across the globe. For rs6754031, the minor allele frequency is approximately 0.35 to 0.45 in European ancestral populations, making both homozygous and heterozygous genotypes common. Large population surveys show that a slight majority of participants in certain cohorts report an inability to perceive the signature asparagus metabolite odor. Most published genetic association studies investigating asparagus anosmia have focused predominantly on individuals of European descent. Consequently, allele frequencies and perceptual thresholds can vary in other global ancestral groups, where further diverse sensory studies are ongoing.
What You Can and Cannot Do with This Result
Your rs6754031 genotype is an interesting genetic trait, often catalogued as a sensory curiosity or fun fact rather than a medical indicator. It does not diagnose any disease, predict health outcomes, or evaluate overall olfactory health. Having a genotype linked to asparagus anosmia simply suggests you may have a higher sensory threshold for detecting specific volatile sulfur metabolites. It does not provide insight into whether your body actually produces the metabolites after asparagus consumption, as metabolic excretion and olfactory detection are governed by distinct physiological pathways. This result is meant for educational and recreational enjoyment rather than medical decision-making.
How common is this variant?
The rs6754031 variant is common globally, with the minor allele frequency estimated between 0.35 and 0.45 in European populations.
Frequently asked questions
What is asparagus anosmia?
Asparagus anosmia is the specific inability to smell the distinct, pungent sulfur compounds produced in human urine after eating asparagus. It is considered a benign specific anosmia rather than a general loss of smell.
Does this gene determine if my urine smells or if I can smell it?
The OR2M7 gene affects your olfactory receptors, which means it influences your ability to smell the metabolites, not whether your digestive system produces them. Some people produce the odor but cannot smell it, while others do not produce detectable levels at all.
Is rs6754031 linked to any disease or health condition?
No, rs6754031 is not known to cause any medical disorders or health complications. It is categorized as a benign, sensory trait variant.
Why can some people smell asparagus pee while others cannot?
Differences in smell perception are primarily due to natural genetic variations in olfactory receptor genes like OR2M7, which alter how sensitive odor receptors are to volatile sulfur metabolites such as methanethiol.
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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Variant influencing the ability to detect distinct scent metabolites in urine after consuming asparagus.
Associated with the specific anosmia or ability to perceive the pungent odor of asparagusic acid metabolites in human urine after asparagus consumption.
Strongly linked with the ability to smell methanethiol and other sulfurous metabolites in urine after asparagus consumption.
Variant in the olfactory receptor cluster strongly linked to the inability to smell the distinct odor of asparagus metabolites in urine (asparagus anosmia).