rs2814778

A SNP in the DARC gene on chromosome 1. Its most notable genotype is T;T: Duffy-positive

Gene
DARC
Location
Chr 1159,204,893 (GRCh38)
Highest magnitude
1.0Minor
Tested on
23andMe, AncestryDNA
Minor allele frequency
22%

Genotypes

Plus strand, as in 23andMe and AncestryDNA files.

  1. T;TMost notableGoodDuffy-positiveMinor · 1.039% of people
  2. C;TGoodDuffy-positiveMinor · 1.011% of people
  3. C;CGoodDuffy-negative, Fy(a-b-) phenotype; resistance to malaria;, increased odds of HIV infection upon exposure, but slowed disease progression if infectedMinor · 1.050% of people

SNPedia records rs2814778 on the minus strand: (A;A), (A;G), (G;G). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.

Frequency

Share of each genotype in 5 HapMap populations.

  • AverageT;T 39% C;T 11% C;C 50%
  • African ancestry (Southwest US)T;T 4% C;T 33% C;C 63%
  • Luhya (Kenya)T;T 0% C;T <1% C;C 99%
  • Mexican ancestry (Los Angeles)T;T 91% C;T 9% C;C 0%
  • Maasai (Kenya)T;T <1% C;T 12% C;C 87%
  • TuscanT;T 98% C;T 2% C;C 0%

Notes

From SNPedia

Show notes, about 180 words

rs2814778 is within the DARC gene, which encodes the Duffy blood group antigen . This SNP shows an almost perfectly fixed difference in frequency between Europeans and those with African ancestry. (One exception appears to be a certain population of Czech gypsies, and certain non-Ashkenazi Jewish populations.) Additionally the Namibian San samples of the CEPH-HGDP are, uncharacteristically for Africans, all AA homozygotes for this SNP. The rs2814778 (G) allele is associated with African populations, while rs2814778 (A) is associated with European populations and southwestern Native American populations. rs2814778(G;G) protect against Plasmodium vivax malaria and predicts of white blood cell and neutrophil count 23andMe blog discussion Malaria Resistance (Duffy Antigen)

T;T

This genotype is associated with European populations and southwestern Native American populations; see discussion and citations at rs2814778.

C;T

see discussion and citations at rs2814778

C;C

See discussion and citations at rs2814778; this is the major Duffy phenotype found in Africans and African-Americans.

Source and license

Adapted from rs2814778 on SNPedia, using a snapshot taken October 16, 2026. SNPedia content is shared under CC BY-NC-SA 3.0 US, and this page is shared under the same license.

SNPedia is a community-edited wiki. Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice. Magnitude is a community rating of how interesting a genotype is, not a risk score.