rs1051730
How many cigarettes a day, if you smoke
What this position does
Sitting in the same nicotine receptor cluster as the dependence variant, and inherited with it. Its effect is measured directly in cigarettes per day, and through that in lung cancer and emphysema risk. Nothing about this was shaped by evolution: tobacco arrived a few hundred years ago and found a receptor system built for something else.
Lungs and reward. Shaped by tobacco, which is 400 years old. This is one of the variants that differs sharply between human populations, because something in the environment made one version worth having.
Pressures with no evolutionary history
Tobacco is about four hundred years old outside the Americas, and the attention economy is about fifteen. Nothing in your DNA is an adaptation to either. These variants are ancient machinery being pulled by something new.
What changed: Industry, roughly the last two centuries. Indoor work, heated buildings, refined food, cheap salt and sugar, tobacco at scale, and a collapse in infectious disease. This is where most of the deals in your genome came undone.
Not an adaptation to anything. The thing this variant responds to arrived far too recently to have shaped it. Ancient machinery, new pull.
Spiral Staircase, chapter 10: The Breath You Forgot How to Take Spiral Staircase is written by the same author as this site.
What each result means
| If you carry | What it means |
|---|---|
| No copies of the effect version GG | You do not carry it The lower-consumption version on both copies. |
| One copy AG | You carry one copy Among smokers, associated with about one extra cigarette a day and a measurably higher lung cancer risk that runs through it. |
| Two copies AA | You carry two copies Among smokers, associated with roughly two extra cigarettes a day and the highest risk at this position. If you smoke, this is an argument for getting real help to stop. |
Worth knowing. Only meaningful if you smoke or have smoked. It says nothing about whether you would start.
How common each version is
| Ancestry group | A (the effect version) | |
|---|---|---|
| African | 8.7% | |
| American | 21.6% | |
| East Asian | 2.7% | |
| European | 36.9% | |
| South Asian | 18.3% |
1000 Genomes Project phase 3, via Ensembl, retrieved 2026-09-23. These groupings are coarse and flatten a great deal of internal diversity, particularly within Africa. A variant being common somewhere tells you where a piece of your ancestry probably comes from, and nothing else.
How many people carry each result
| Ancestry group | GG | AG | AA |
|---|---|---|---|
| African | 552 / 661 | 103 / 661 | 6 / 661 |
| European | 203 / 503 | 229 / 503 | 71 / 503 |
| East Asian | 477 / 504 | 27 / 504 | 0 / 504 |
| South Asian | 331 / 489 | 137 / 489 | 21 / 489 |
| American | 220 / 347 | 104 / 347 | 23 / 347 |
Counts of people, not modelled frequencies: every one of the 2,504 individuals sequenced by the 1000 Genomes Project phase 3, tallied by the genotype they carry. Deriving these from allele frequencies instead would assume random mating inside each group and undercount the homozygotes.
How to find out which you have
If you have taken a test with 23andMe, AncestryDNA, MyHeritage, Family Tree DNA, TellMeGen or Living DNA, this position is very likely already in the raw data file they gave you. You do not need another test.
One thing to watch if you look it up by hand: testing companies report some positions from one DNA strand and some from the other, and the file does not say which. Read the letters as they appear and you will get the opposite of the truth for some positions. Sequencings resolves that automatically.
Source
Coordinates and allele pair verified against Ensembl GRCh37. Direction of effect verified against VEP protein consequences or 1000 Genomes population frequency. Category: Population adaptation.
Where this fits
Common questions
What is rs1051730?
rs1051730 is a position in the CHRNA3 gene on chromosome 15. Sitting in the same nicotine receptor cluster as the dependence variant, and inherited with it. Its effect is measured directly in cigarettes per day, and through that in lung cancer and emphysema risk. Nothing about this was shaped by evolution: tobacco arrived a few hundred years ago and found a receptor system built for something else.
What does it mean if I have AA at rs1051730?
You carry two copies. Among smokers, associated with roughly two extra cigarettes a day and the highest risk at this position. If you smoke, this is an argument for getting real help to stop.
What does it mean if I have GG at rs1051730?
You do not carry it. The lower-consumption version on both copies.
How do I find out my rs1051730 genotype?
If you have taken a home DNA test, this position is very likely in the raw data file you were given. Sequencings reads that file in your browser without uploading it, and resolves which DNA strand each position was reported from, which is the step most manual lookups get wrong.
This is reference information, not medical advice, and not a diagnosis. See the medical disclaimer. Category: Population adaptation.