A worldwide correlation of lactase persistence phenotype and genotypes

Area of Science:

• Human Genetics
• Evolutionary Biology
• Population Studies

Background:

• Lactase persistence, the adult ability to digest lactose, is a Mendelian trait with varied global prevalence.
• Known genetic variants strongly associate with lactase persistence in specific populations, enabling potential genetic testing.
• Existing genetic knowledge may not encompass all lactase persistence variants worldwide.

Purpose of the Study:

• To assess the extent to which current genetic data explains observed lactase persistence phenotype frequencies globally.
• To identify regions where genetic knowledge is insufficient to explain trait prevalence.

Main Methods:

• Utilized surface interpolation of global lactase persistence genotype and phenotype frequencies from existing literature.
• Compared predicted trait frequencies with observed frequencies across continuous space.
• Employed Monte Carlo methods, incorporating sample size and phenotype test accuracy, to estimate explanatory power of known variants.

Main Results:

• Current genotype data inadequately explains lactase persistence phenotype frequencies in large parts of Africa, Europe, the Middle East, and Asia.
• Significant discrepancies exist between predicted and observed trait frequencies in several key regions.

Conclusions:

• Lactase persistence genotype data is insufficient to explain phenotype frequencies in western/southern Africa, southeastern Europe, the Middle East, and central/southern Asia.
• Further research into genetic variation in these regions is crucial to discover additional lactase persistence-associated nucleotide variants.