The mutation is lactose tolerance. Originally we were all intolerant. Regards.
That is speculation. Lactose is present in all mammalian milk.
Lactose intolerance and the breastfed baby
Lactose is the sugar in all mammalian milks. It is produced in the breast and is independent of the mother's consumption of lactose. It is present in a constant concentration in breastmilk.
Primary (or true) lactose intolerance is an extremely rare genetic condition and is incompatible with normal life without medical intervention.
Thanks. Sure enough the article says lactose tolerance and not intolerance.