Example of a Mechanism for Lactase Persistence
The mutation that arose in northern Europe strengthens the binding of a transcription factor called Oct-1 to the enhancer region. There is evidence that Oct-1 is an activator for LCT—so it would increase the transcription of the LCT gene.
Interestingly, the mutation that arose in Africa appears to use a different mechanism. Research is ongoing to reveal the various mechanisms of lactase persistence.