Evidence · Replicated

What the research found

In the cited research, the T allele at rs921943 was associated with higher blood selenium concentrations in the studied cohorts.

CC: Lower average
CT: Middle
TT: Higher average

Modest effect

What the study found

In the study, each copy went with higher blood selenium on average.

Australian adult twins and families (QIMR, red-cell selenium) and pregnant UK women (ALSPAC, whole-blood selenium) · Table 1 (meta-analysis columns)

Evidence: Genome-wide association supported in two independent cohorts
Who was studied: Australian adult twins and families and pregnant women from the UK ALSPAC cohort

1000 Genomes Project

How common each genotype is

How common each genotype is in the 1000 Genomes Project, by region
Region	CCLower average	CTMiddle	TTHigher average
All regions2,504 people	50%	39%	11%
Africa661 people	26%	47%	27%
The Americas347 people	66%	28%	6%
East Asia504 people	74%	25%	2%
Europe503 people	49%	43%	8%
South Asia489 people	48%	44%	8%

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	12%3 of 25 copies read
First farmers6500 to 3000 BC	25%62 of 246 copies read
Bronze Age3000 to 1200 BC	20%30 of 150 copies read
Iron Age and Antiquity1200 BC to AD 600	27%72 of 268 copies read
Middle AgesAD 600 to 1500	25%65 of 261 copies read
Today1000 Genomes	30%297 of 1,006 copies

Neanderthal and Denisovan genomes

Altai Neanderthal: No copies
Vindija Neanderthal: No copies
Chagyrskaya Neanderthal: No copies
Denisovan: No copies

Neanderthals and Denisovans carried the other letter, so this letter is younger than our split with them.

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.

rs921943

The marker

Gene or region: DMGDH region
Marker: rs921943
Location: Chromosome 5 · GRCh37 78,316,476 · GRCh38 79,020,653
Letters studied: C and T, with T 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: DMGDH region · rs921943
Location: Chromosome 5 · GRCh37 78,316,476 · GRCh38 79,020,653
Studied allele: T
Published statistic: beta 0.246 SD per T allele (SE 0.023), P 9.40e-28 (meta-analysis); QIMR 0.222 (SE 0.034), P 9.33e-11, N 2,603; ALSPAC 0.264 (SE 0.030), P 1.43e-18, N 2,874; Table 1; 0.25 SD per copy (Table 1 (meta-analysis columns))
1000 Genomes Project phase 3, people with 0, 1 and 2 copies: All regions 1255 / 966 / 283 · Africa 173 / 312 / 176 · The Americas 230 / 97 / 20 · East Asia 372 / 124 / 8 · Europe 246 / 217 / 40 · South Asia 234 / 216 / 39

See this card in the sample report

Limits

What it cannot tell you

The cohorts measured selenium in red blood cells or whole blood. This association does not measure serum selenium, total-body selenium, antioxidant activity or selenium requirements. Only the studied C/T allele pair is interpreted. It cannot tell you a current selenium level, is not a test for deficiency and cannot choose a diet, supplement or dose.

Genome-wide association study identifies loci affecting blood copper, selenium and zinc (Evans et al., 2013)

The same topic

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