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Lactase-persistence is the continued function of the lactase enzyme in adulthood. If you are lactase persistent, you are (usually) able to drink milk as an adult. Since it’s more common to be lactose intolerant in most populations, the genetic condition for being able to tolerate lactose into adulthood is referred to as lactase persistence.
This table shows that 12.3% of Africans have one or more alleles for lactase persistence, 57.1% of Finnish Europeans have alleles for lactase persistence, 0% of South Asians have alleles for lactase persistence, 0.06% of East Asians have alleles for lactase persistence, 10% of Ashkenazi Jews have alleles for lactase persistence, 60.1% of non-Finnish Europeans have alleles for lactase persistence and 20.3% of Latinos have alleles for lactase persistence. In other words, Asians are the most likely population to be lactose intolerant because of decreased activity of the lactase enzyme and non-Finnish Europeans are the least likely to be lactose intolerance from persistence of the lactase enzyme.
If you were to use this single genetic polymorphism as an estimate of lactose intolerance, you would assume that lactose intolerance is the least for non-Finnish European and the most for South and East Asian.
Interestingly, while Latinos are predicted to be more tolerant than Africans by genetics, 60-100% of the Latino population is predicted to be lactose intolerant.
Estimated lactose intolerance genetics by ethnicity from most intolerance to least intolerance (data from gnomAD):
South Asian
East Asian
Ashkenazi Jewish
African
Latino
European (Finnish)
European (non-Finish)
https://archive.is/Utkaq#selection-271.0-291.106Did you know that 65% of the Human population has a reduced ability to digest lactose after infancy? Inversely, only about 5% of people in Northern European descent are lactose intolerant. But when you look at the Chinese population, over 90% are lactose intolerant. How can this be? It’s because of the LCT/MCM6 gene — LCT is one of my favorite genes! This gene is so interesting because it contains an important genetic polymorphism (rs4988235) that are highly variable in different populations. This genetic polymorphism causes lactase persistence.
Comparing Lactose Intolerance Genetic Polymorphisms to a Worldwide Prevalence Map of Lactose Intolerance:
https://archive.is/Utkaq/161e10be96b...3f4fe4e74.webp
Here's a table of lactose intolerance by country: https://archive.is/Utkaq#selection-547.0-547.49
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