Evidence · Replicated

What the research found

In the cited research, the C allele at rs7800944 was associated with slightly more cups of coffee a day among coffee drinkers.

TT: Fewer cups
CT: Middle
CC: More cups

What the study found

In the study, each copy went with cups of coffee a day among coffee drinkers about 0.05 cups a day higher on average.

Coffee drinkers of European and African American ancestry, all discovery and replication cohorts combined · 116,417 people · Table 1, rs7800944 row, trans-ethnic meta-analysis columns (effect from the random-effects meta-analysis of all stage 1 and stage 2 studies, footnote c; n in the row's last column)

Evidence: Genome-wide meta-analysis with independent replication
Who was studied: European ancestry, with African American follow-up

1000 Genomes Project

How common each genotype is

How common each genotype is in the 1000 Genomes Project, by region
Region	TTFewer cups	CTMiddle	CCMore cups
All regions2,504 people	62%	32%	6%
Africa661 people	42%	48%	11%
The Americas347 people	76%	22%	3%
East Asia504 people	79%	19%	2%
Europe503 people	56%	37%	7%
South Asia489 people	72%	24%	4%

Among the 2,504 people of the 1000 Genomes Project, in five world regions. These percentages describe groups of people, never anyone’s chance of having a trait.

Ancient genomes

Through time

How often the studied letter was read in ancient people, era by era, in the region chosen.

Region

Through time: Europe
Before farmingbefore 6500 BC	25%7 of 28 copies read
First farmers6500 to 3000 BC	38%88 of 229 copies read
Bronze Age3000 to 1200 BC	28%40 of 142 copies read
Iron Age and Antiquity1200 BC to AD 600	25%55 of 218 copies read
Middle AgesAD 600 to 1500	24%58 of 237 copies read
Today1000 Genomes	26%259 of 1,006 copies

Neanderthal and Denisovan genomes

Altai Neanderthal: Not read
Vindija Neanderthal: Not read
Chagyrskaya Neanderthal: 2 copies
Denisovan: Not read

For most ancient people only one of their two copies can be read, so these counts are copies read, not people. Close relatives, repeated samples and samples the archive marks as unreliable are left out. Damage in old DNA can fake this letter, so it is counted only from samples treated to remove that damage and from high-quality genomes. Ancient genomes from the Allen Ancient DNA Resource (AADR v66): 15,136 people.

rs7800944

The marker

Gene or region: MLXIPL
Marker: rs7800944
Location: Chromosome 7 · GRCh37 73,035,857 · GRCh38 73,621,527
Letters studied: C and T, with C as the studied allele

A DNA Traits report reads this marker in your raw DNA file and shows which of the three genotypes is yours, with how common it is. It counts the copies of the studied allele; it does not measure the trait itself.

Marker: MLXIPL · rs7800944
Location: Chromosome 7 · GRCh37 73,035,857 · GRCh38 73,621,527
Studied allele: C
Published statistic: Per T, cups a day (Cornelis 2015 Table 1): stage 1 -0.05 (SE 0.01), P 7.82e-9 (EUR n <= 91,462); stage 2 European -0.06 (0.02), P 4.20e-4 (n <= 30,062); African American -0.02 (0.02), P 0.37 (n <= 7,964); all stages -0.05 (0.01), log10 Bayes factor 8.83, n 116,417. The card counts C, so each printed beta flips sign (Table 1, rs7800944 row, trans-ethnic meta-analysis columns (effect from the random-effects meta-analysis of all stage 1 and stage 2 studies, footnote c; n in the row's last column))
1000 Genomes Project phase 3, people with 0, 1 and 2 copies: All regions 1563 / 796 / 145 · Africa 275 / 316 / 70 · The Americas 262 / 76 / 9 · East Asia 396 / 98 / 10 · Europe 280 / 187 / 36 · South Asia 350 / 119 / 20

See this card in the sample report

Limits

What it cannot tell you

Intake was reported as cups a day by coffee drinkers, and the study prints no figure that rates the size of the effect.

Genome-wide meta-analysis identifies six novel loci associated with habitual coffee consumption (Coffee and Caffeine Genetics Consortium, Cornelis et al., 2015)

The same topic

More in Nutrition & metabolism

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