EDAR rs7688678: Understanding This Genetic Variant
The rs7688678 variant is an intronic genetic marker located within the EDAR gene. It is primarily studied for its strong statistical associations with physical traits such as hair follicle density, tooth morphology, and sweat gland development in East Asian populations.
What each genotype means
Ancestral hair and sweat profile
This genotype represents the ancestral state of the EDAR variant. Research indicates this version is associated with lower hair follicle density and different sweat gland distribution compared to the derived allele, and it is the predominant form in populations of African and European ancestry.
This genotype is extremely common in African and European populations but is rare in East Asian populations.
Heterozygous hair and sweat profile
Carrying one copy of the derived allele may result in intermediate phenotypic expression regarding hair follicle density and sweat gland branching. Because this variant is linked to adaptive traits in East Asian populations, the functional impact of a single copy is often observed as a shift toward the derived phenotype.
This genotype is found at varying frequencies in populations with mixed ancestry or those with significant East Asian genetic heritage.
Derived hair and sweat profile
This genotype is associated with the derived EDAR variant, which has been under strong positive selection in East Asian populations. It is statistically linked to increased hair follicle density, thicker hair shafts, and specific sweat gland branching patterns, reflecting an adaptive evolutionary history.
This genotype is highly prevalent in East Asian and Native American populations, often reaching frequencies of 70% to 90%.
What is rs7688678?
The rs7688678 variant is a single nucleotide polymorphism (SNP) situated within the EDAR gene. In genetics, an intronic variant refers to a change in the DNA sequence that occurs within an intron—a non-coding region of a gene that is removed during the process of creating a protein. While intronic variants do not directly alter the amino acid sequence of a protein, they often function as regulatory elements. These elements can influence how much of a protein is produced, when it is produced, or in which tissues it is expressed. Because rs7688678 is located in a region of the genome that is tightly linked to other functional variants in the EDAR gene, it is frequently used by researchers as a marker to track the inheritance of specific genetic patterns associated with physical traits.
The Role of the EDAR Gene
The EDAR gene provides instructions for making a protein called the ectodysplasin A receptor. This receptor is a critical component of a signaling pathway that facilitates communication between different layers of the skin during embryonic development. This pathway is essential for the proper formation of ectodermal structures, which include hair follicles, sweat glands, and teeth. When this signaling pathway functions correctly, it ensures that these structures develop in the right patterns and densities. Mutations that disrupt the function of the EDAR protein can lead to a group of conditions known as hypohidrotic ectodermal dysplasia, which are characterized by sparse hair, reduced ability to sweat, and missing or malformed teeth. Because of its central role in these developmental processes, variations in EDAR are of significant interest to evolutionary biologists and geneticists studying human physical diversity.
Research and Associations
Research into EDAR variants has revealed that certain alleles have been driven to high frequency in East Asian and Native American populations due to ancient positive selection. The rs7688678 variant is often studied alongside other nearby variants, such as rs3827760, which is known to encode a more potent version of the EDAR receptor. Studies have linked these genetic patterns to specific physical characteristics, including increased hair thickness, the presence of shovel-shaped incisors, and higher densities of sweat glands on the fingertips. It is important to note that the evidence for these associations is largely statistical, derived from genome-wide association studies (GWAS). While these correlations are robust in specific populations, they represent complex traits influenced by many genes and environmental factors. The evidence strength for any single intronic marker like rs7688678 is considered limited in terms of predicting an individual's specific physical appearance.
Interpreting Your Genetic Information
If you encounter information about your genotype for rs7688678, it is helpful to understand that this data is primarily of interest for ancestry and evolutionary studies. Because this variant is associated with normal human physical variation rather than a medical condition, it does not provide information about your health status or disease risk. You cannot use this information to diagnose any condition or to predict specific physical traits with certainty. Genetic associations are based on population-level data and do not account for the unique combination of genes and environmental influences that shape an individual. If you have concerns about your health, such as issues related to skin, hair, or dental development, you should consult with a qualified healthcare professional. They can provide a clinical evaluation that is far more accurate and relevant than any single genetic marker.
How common is this variant?
The derived allele associated with this variant is found at a frequency of approximately 0.70 to 0.85 in East Asian populations, while it is near 0 in African and European populations.
Frequently asked questions
Is rs7688678 linked to a disease?
No, rs7688678 is not considered a disease-causing variant. It is a common polymorphism associated with normal physical traits like hair and tooth shape.
Can this variant predict my hair type?
While rs7688678 is statistically associated with hair thickness in certain populations, it cannot accurately predict your individual hair type. Many different genes and environmental factors contribute to hair characteristics.
Why is this variant common in some populations but not others?
This variant reached high frequencies in East Asian and Native American populations due to ancient positive selection. This means the variant likely provided an evolutionary advantage in those environments in the past.
Should I be concerned if I have the G/G genotype?
There is no reason for concern. The G/G genotype is a normal variation found in a large portion of the global population and is not associated with any medical condition.
Sources & further reading
Educational information only, last refreshed 10/15/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Functional variant tightly linked to hair shaft thickness, sweat gland density, and distinct East Asian dental morphology traits.
Functional variant (V370A) in the EDAR gene influencing hair thickness and sweat gland density.
Non-coding regulatory variant in EDAR associated with variations in hair fiber thickness, crown morphology, and dental traits.
The 370A (Val370Ala) variant is a classic example of positive selection in East Asian and Native American populations, affecting hair thickness and sweat gland density.
Common regulatory variant in the EDAR region associated with variation in human hair thickness, beard density, and facial shape.
Functional variant in EDAR associated with hair fiber diameter and dental morphology.