SISG MODULE 8

This module covers the basic statistical and genetic methods and principles central to forensic analysis.  These include the derivation of likelihood ratios (LRs) for the presentation and evaluation of genetic evidence based on autosomal, mitochondrial, and Y-chromosome short tandem repeat markers.

The module provides the background necessary for using analysis results from packages such as CODIS Popstats; Describes mutation processes, genotyping technology, and special considerations in the use of forensic STR markers; Reviews principles of population genetics, and measurement of relatedness; and Addresses the complications of mixture interpretation when the queried contributor is a relative of the true contributor.

The module is suitable for graduate students in population genetics, forensic science practitioners, and lawyers facing DNA evidence.

Learning Objectives: After attending this module, participants will be able to: 

1. Calculate single-locus likelihood ratios for a binary model with specified propositions under simplified settings (i.e. assuming no population structure or STR typing anomalies). 

2. Identify and describe the three main likelihood ratio modeling approaches, including their strengths and limitations. 

3. Describe the hierarchy of propositions, and identify and formulate them in a case setting.

4. Understand and detect bias in forensic settings, including recognizing the prosecution fallacy and the association fallacy. 

5. Predict kinship levels for pairs of individuals in pedigrees and interpret the forensic implications. 

6. Understand emerging new molecular profiling techniques for human identification.

Bruce Weir is Professor Emeritus of Biostatistics at the University of Washington, Seattle, and holds adjunct appointments at Massey, Otago and Auckland Universities in New Zealand.  He was the founding Director of the Summer Institutes in Statistical Genetics for 28 years, and is a Fellow of the Royal Society, in recognition of his contributions to forensic genetic inference and statistical measurement of population structure. Learn more about Bruce’s work here.