Chapter E, Problem 12P

Three independently assorting STR markers (A, B, and C) are used to assess the paternity of a colt recently born to a quarter horse mare. Blood samples are drawn from the mare, her colt, and three possible male sires ( $\text{S1}$, $\text{S2}$, and $\text{S3}$). DNA at each marker locus is amplified by PCR, and a DNA electrophoresis gel is run for each marker. Amplified DNA bands are visualized in each gel by ethidium bromide stain-ing. Gel results are shown below for each marker.

a. Evaluate the data and determine if any of the potential sites can be excluded. Explain the basis of exclusion, if any, in each case.

b. Calculate the PI and CPI based on these STR markers, using the following population frequencies: $\text{A12 = 0}\text{.12, A10 = 0}\text{.18; B18 = 0}\text{.08, B12 = 0}\text{.17; C16 = 0}\text{.11, C14 = 0}\text{.20}$.