{{Rsnum
|rsid=6591536
|Gene=OR5A1
|Chromosome=11
|position=59443715
|Orientation=plus
|GMAF=0.3747
|Gene_s=OR5A1
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|geno1=(A;A)
|geno2=(A;G)
|geno3=(G;G)
}}{{ population diversity
| geno1=(A;A)
| geno2=(A;G)
| geno3=(G;G)
| CEU | 41.6 | 39.8 | 18.6
| HCB | 56.9 | 34.3 | 8.8
| JPT | 54.0 | 36.3 | 9.7
| YRI | 21.1 | 43.5 | 35.4
| ASW | 26.3 | 47.4 | 26.3
| CHB | 56.9 | 34.3 | 8.8
| CHD | 56.5 | 38.9 | 4.6
| GIH | 61.4 | 30.7 | 7.9
| LWK | 20.0 | 52.7 | 27.3
| MEX | 37.9 | 36.2 | 25.9
| MKK | 23.1 | 48.1 | 28.8
| TSI | 54.9 | 37.3 | 7.8
| HapMapRevision=28
}}[[rs6591536]], also known as N183D or Asn183Asp, is a SNP in the olfactory receptor, family 5, subfamily A, member 1 [[OR5A1]] gene. The [[rs6591536]](A) allele encodes the asparagine (N).

Individuals vary in their ability to [[smell]] various odors, largely due to variations in their olfactory receptors. Carriers of one or two [[rs6591536]](G) alleles can detect a particular compound, β-ionone, at levels two orders of magnitude lower than [[rs6591536]](A;A) individuals. In fact, this study reports that 96% of the observed phenotypic variation is determined by this single SNP, making it nearly a completely Mendelian trait. People with high or low β-ionone sensitivity are found in all populations, and based on this SNP, variability was seen even in [[Neanderthal]] populations.{{PMID|23910657}}

Since [[rs6591536]] determines β-ionone odor sensitivity, generally described as "floral", preferences may depend on genotypes at this SNP. The same study cited above found that on average, high-sensitivity individuals were more likely to prefer fragrances and household products containing β-ionone than low-sensitivity individuals, whereas when in food products such as beverages and chocolates, high-sensitivity individuals rated them lower than low-sensitivity individuals. In general, low-sensitivity individuals, i.e. [[rs6591536]](A;A) individuals, were less likely to perceive the β-ionone for good (in scented household products) or for bad (in foods).{{PMID|23910657}}

β-ionone has anti-cancer properties{{PMID|18386789}}, however it is unknown whether differences in β-ionone flavor sensitivity affect cancer risk by changing the amount of β-ionone people consume.

{{on chip | 23andMe v1}}
{{on chip | 23andMe v2}}
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{{on chip | FTDNA2}}
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{{on chip | HumanOmni1Quad}}
{{on chip | Illumina Human 1M}}