>>519762913
Every bit of DNA code is a mutation. That is how life works, every single individual lifeform that comes into existence has mutations. That is why individuals are unique. Sometimes mutations are very useful for survival and procreation, so they are passed on and preserved. Sometimes the same mutation happens more than once. Even the most basic bits of DNA code that are shared by 99% of life on earth, was originally a mutation.

>>519763035
Nope. First humans with lactose tolerance were Late Neolithic semi-sedentary pastoralists around 6200-5800BC in Northern Mesopotamia (modern-day Syria and Iraq), the Levant (modern-day Israel and Lebanon) and Anatolia (modern-day Turkey). Humans probably started milking goat and sheep around 6500BC in sedentary societies heavily reliant on agriculture. Around 6200BC a minor shift in climate occurred known as the 8.2k cal BP event, which reduced temperatures and precipitation in the area.

Societies shifted towards more mobile lifestyles, relying more on domesticated animals, pottery use increased and there is evidence of individuals moving between communities. It's likely milk consumption helped them offset variability in crop yields caused by the 8.2k. The oldest genetic evidence of lactose tolerance is dated to around 5500BC in Northern Africa, in modern Libya and Egypt.

They possibly also made cheese (pic related)