In dr. Hill's research, he discovers that 3 children in his study that have maple syrup urine disease (MSUD), a recessive genetic disorder that prevents that body from processing certain amino acids. Since MSUD occurs in only around 1 in 185,000 infants worldwide, 3 cases in a population of 1000 is usually high. Dr. Hill has two hypotheses to explain this. The first has to do with the original settlers. Name the process he has in mind