### Links

Powerpoint for this web page
Forensic mathematics home page
Spanish-Portuguese ISFG section

# Forensic Mathematics slide show talk

presented at La Gomera, Canary Islands, June 3, 1999
Charles Brenner, Ph.D., Consulting in forensic mathematics

## Strategies and calculations in DNA kinship cases

### Likelihood ratio for being French

Data: Subject speaks 100 French words in 1 hour
• Explanation #1: subject is French
• 20% event
• Explanation #2: subject is not French
• 1% event
• LR=20; Data is 20 times more characteristic of French person

## Paternity

### Likelihood ratio for paternity (PI)

• PI = X/Y, where
• X=P(genetic types | man=father)
• Y=P(genetic types | man not father)
• Interpretations:
• Odds favoring paternity over non-paternity assuming all other evidence
• is equally divided
• Evidence is PI times more characteristic of paternity
• What the "exclusion" method is
• Likelihood ratio for Paternity (PI)
• Other basic kinship situations
• Avuncular index (Is the man an uncle?)
• Other kinship cases
• Missing person kinship case
• Other applications of the likelihood ratio
• Null allele
• Mutation
• PI when possible mutation
• Mutation analysis: concept
• Paternity case: one "exclusion"
• Paternity case: two "exclusions"
• Mutation (old method)
• Old mutation formula
• Old mutation formula is
• Mutation model (old formula)
• Mutation model (more realistic)
• Reasonable mutation model, STR's
• Mutation LR (new, for STR's)
• STR mutation rates
• Mutation reference
• Kinship II (advanced)
• More than two scenarios
• Three scenarios –
• Father/Uncle/Unrelated analysis
• Likelihood ratios are "transitive"
• DNA-VIEW software
• Summary
• Thanks

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