Introduction:
Court cases involving identification of individuals are now routinely presented with genetic materials as evidence. What is the biological nature of such evidence? What does a statement such as "the probability of a match for two unrelated individuals is 3 in 100 billion." mean? How is the number calculated? How reliable is the number, and its interpretation? This fascinating intersection of law, biology and statistics has evolved through many legal and intellectual debates (wars). The aim of this module is to gain some understanding of the basic issues, with emphasis on the quantitative aspects of DNA evidence. The student will then apply the knowledge to interpret some real legal cases. Requisite knowledge in the relevant fields will be developed in the module.
Organization:
The module will mostly be run in a seminar style: active discussion is most encouraged. Some topics to be covered:
| (1) |
Law: admissible evidence, reasonable doubt, People vs Collins, DNA finger-printing. |
| (2) |
Biology: Mendel's laws of inheritance, DNA, locus, allele, genotype, variable number tandem repeats, Hardy-Weinberg equilibrium. |
| (3) |
Descriptive statistics: population proportion, conditional proportion, multiplication rule, independent genotypes, addition rule, mutually exclusive genotypes, Bayes' rule. |
| (4) |
Reasoning with proportions: likelihood, likelihood ratio, prosecutor's fallacy. |
| (5) |
Probability: interpretation, other notions: in (3), replace "proportion" and "genotype" by "probability" and "event" respectively. |
| (6) |
Sampling: estimation, standard error. |
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