Interesting bit of interdisciplinary work on the spread of lactase persistance:
Thomas found that the gene variant coincided well with the rise of animal domestication, indicating that humans became dairy farmers almost as soon as they began to keep animals.
To track the gene’s spread across Europe, Thomas designed a computer model that took into account both archaeological and genetic data. He then ran multiple simulations, randomly changing other variables and looking for patterns that matched what is known today.
The closest matches pegged the rise of milk-drinking Europeans to about 7,400 years ago in central Europe. The spread matched the known rapid spread of Europe’s first farmers, the Linearbandkeramik culture.
“The spread of the LP variation was shaped by selection and by an underlying demographic process, the spread of farming,” Thomas said.
Related: Posts on lactase persistence.