LCT rs7795355: Understanding Lactase Persistence Variants
The rs7795355 variant is a genetic marker located near the LCT gene, which encodes the enzyme responsible for digesting lactose. It is primarily studied for its association with lactase persistence, the ability to digest milk sugar into adulthood, particularly in pastoralist populations of Sub-Saharan Africa.
What each genotype means
Likely lactase non-persistent
This genotype is associated with the typical decline in lactase enzyme activity after childhood. Individuals with this profile may experience symptoms of lactose intolerance, such as bloating or digestive discomfort, after consuming dairy products. This association is based on studies of pastoralist populations where this specific variant is found.
This genotype is common in many global populations, though its frequency varies significantly depending on ancestral background.
Potential lactase persistence
Carrying one copy of the G allele may influence the regulation of the lactase gene, potentially allowing for continued lactase production into adulthood. Research suggests this allele acts as an enhancer for LCT expression, which is linked to the ability to digest lactose. Individual experiences with dairy digestion can still vary widely regardless of this genetic marker.
This genotype is observed at notable frequencies in specific East African pastoralist groups and is rare in most other global populations.
Likely lactase persistent
This genotype is associated with the maintenance of lactase enzyme activity into adulthood, a trait known as lactase persistence. Research indicates that the G allele functions as an enhancer that prevents the typical downregulation of the lactase gene. Individuals with this profile are statistically more likely to digest lactose without symptoms, though this is not a guarantee of tolerance.
This genotype is enriched in certain East African pastoralist populations and is virtually absent in European and East Asian populations.
What is rs7795355 and Where is it Located?
The variant rs7795355 is a single nucleotide polymorphism (SNP) situated within the regulatory regions upstream of the LCT gene. Specifically, it is located within an intron of the neighboring MCM6 gene. This region is critical because it acts as an enhancer, a segment of DNA that controls the expression of the nearby LCT gene. While the LCT gene itself provides the instructions for creating the lactase enzyme, the variants in the MCM6 region determine whether the production of this enzyme continues after the weaning period. By influencing the activity of the LCT promoter, these regulatory variants can dictate whether an individual maintains the ability to digest lactose throughout their adult life or experiences a natural decline in lactase production.
The Role of the LCT Gene
The LCT gene encodes the enzyme lactase-phlorizin hydrolase, commonly known as lactase. In most mammals, the expression of this gene is high during infancy to facilitate the digestion of breast milk but naturally decreases after weaning. This process, known as lactase non-persistence, leads to lactose intolerance in many adults. However, in certain human populations, genetic mutations in the regulatory elements of the LCT gene allow for the continued production of lactase into adulthood. This trait, called lactase persistence, is considered a classic example of human evolutionary adaptation. It is strongly linked to the historical development of dairying and pastoralist cultures, where the ability to consume milk provided a significant nutritional advantage in environments where other food sources might have been seasonally scarce.
Research Associations and Evidence Strength
Research into rs7795355 has identified it as a functional enhancer polymorphism associated with lactase persistence in Sub-Saharan African pastoralist groups. The evidence for this association is considered limited compared to more widely studied variants like the European-associated -13910*T allele. While studies have observed that rs7795355 is enriched in populations with a long history of cattle herding, the functional impact of this specific SNP is still being characterized. It is important to note that lactase persistence is a complex trait influenced by multiple independent genetic variants across different global populations. Because the evidence is ancestry-specific and the functional mechanisms are still under investigation, researchers caution against using this single marker to predict an individual's ability to digest lactose without clinical confirmation.
Population Frequency and Distribution
The distribution of lactase persistence variants is highly variable across the globe, reflecting different histories of human migration and cultural adaptation. The rs7795355 variant is notably enriched in East African pastoralist groups, where it can reach frequencies of 30-40%. In contrast, this variant is virtually absent in East Asian and European populations, where other distinct genetic markers are responsible for the lactase persistence trait. This patchy distribution highlights the convergent evolution of lactase persistence, where different genetic solutions emerged independently in various parts of the world to address the same nutritional challenge. Understanding these frequency differences is essential for researchers studying human population genetics and the history of human dietary adaptations.
What This Information Means for You
Genetic information regarding variants like rs7795355 is primarily used for scientific research into human evolution and population history. It is not a diagnostic tool for lactose intolerance. Lactose intolerance is a clinical condition that should be evaluated by a healthcare professional through symptoms and, if necessary, medical testing such as a hydrogen breath test or a lactose tolerance test. Knowing your genotype for a specific SNP does not provide a complete picture of your physiological response to dairy, as other genetic and environmental factors play a role. If you have concerns about your digestive health or suspect you have lactose intolerance, please consult with your doctor or a registered dietitian to discuss appropriate dietary management and testing options.
How common is this variant?
The rs7795355 variant is enriched up to 30-40% in East African pastoralist groups and is virtually absent in East Asian and European populations.
Frequently asked questions
Is rs7795355 a test for lactose intolerance?
No, rs7795355 is a genetic marker used in research and is not a clinical diagnostic test for lactose intolerance. Lactose intolerance is a clinical diagnosis that should be confirmed by a healthcare provider.
Why is this variant common in some African populations but not others?
The prevalence of this variant is linked to the history of pastoralism and cattle herding in specific regions. Populations that relied on milk as a primary food source were under evolutionary pressure to maintain lactase production into adulthood.
Can I use this genotype to change my diet?
You should not make dietary changes based on a single genetic variant. If you experience digestive issues after consuming dairy, consult a doctor or dietitian to determine the cause and appropriate management.
Are there other genes involved in lactose digestion?
Yes, while the LCT gene and its regulatory regions in MCM6 are the primary drivers, lactose digestion is a complex trait. Other factors, including the gut microbiome and overall digestive health, also influence how you process lactose.
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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Rare variant in the lactase persistence locus marking archaic Eurasian and pastoralist ancestral haplotype variation.
This variant is the primary genetic marker for lactase persistence, determining the ability to digest lactose into adulthood.
This variant near the LCT gene determines whether you keep producing lactase into adulthood. The genotype associated with lactase persistence means you likely tolerate dairy well.
This variant is located in the regulatory region of the lactase gene and is strongly associated with lactase persistence (the ability to digest lactose into adulthood).