The incidence of spinal muscular atrophy (an autosomal recessive disease) in the United States is about 1 case in every 17,000. Whereas, in North Dakota, the prevalence is 1 in 6720. Which of the following would support the hypothesis that genetic drift was responsible for the increased allele frequency in North Dakota? A. There is an abnormally high concentration of mutagenic chemicals in the ground water causing an increased mutation rate in North Dakota.
B. One of the best treatment centers for SMA is located in North Dakota causing migration of SMA carriers into the area at an abnormally high frequency
C. The original settlers of North Dakota were a small group of pioneers who happened to have an abnormally high frequency of the SMA allele in their population.
D. A particular mosquito-born parasite native to North Dakota causes high infant mortality; carriers of the SMA allele are less likely to catch the disease.