- Joined
- Mar 4, 2019
Except, in western populations, and that one african pastoralist tribe, it is a genetic mutation. The genetic change is in the genes that would normally deactivate lactose production after early childhood. Normally, lactase control genes are chemically deactivated after a juvenile weans from its mother. This is true for all mammals, except for human populations. In those populations with lactase persistence, that gene is damaged, so the lactose-production-determining genes aren't deactivated and the population can continue to consume lactose into adulthood.Don't let them tell you it's just a mutation, either.
The scenario you describe isn't the same thing. The man may or may not have been previously lactose-tolerant and may have been suffering from a disruption of his gut flora, which was corrected by the implant. Or, he may have unwittingly had lactic-adic-producing bacteria introduced into his gut. It's believed the presence of certain kinds of lactic-acid-producing gut flora might explain how some populations can tolerate lactose without the mutations for lactase persistence, but it also means they derive no nutritional value from the lactose, unlike people who have lactase persistence genes.