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Current forensic DNA profiles use 10-13 loci to estimate expected genotype frequencies. Problem 2.1 gives a 10-locus genotype for the same individual in Table 2.2, allowing you to calculate the odds ratio for a realistic example. In Chapter 4 we will reconsider the expected frequency of a DNA profile with the added complication of allele-frequency differentiation among human racial groups.

Testing for Hardy-Weinberg

A common use of Hardy-Weinberg expectations is to test for deviations from its null model. Populations with genotype frequencies that do not fit Hardy-Weinberg expectations are evidence that one or more of the evolutionary processes embodied in the assumptions of Hardy-Weinberg are acting to determine genotype frequencies. Our null hypothesis is that genotype frequencies meet Hardy-Weinberg expectations within some degree of estimation error. Genotype frequencies that are not close to Hardy-Weinberg expectations allow us to reject this null hypothesis. The processes in the list of assumptions then become possible alternative hypotheses to explain observed genotype frequencies. In this section we will work through a hypothesis test for Hardy-Weinberg equilibrium.

The first example uses observed genotypes for the MN blood group, a single locus in humans that has

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