1. 1 Familias Thore Egeland, Rikshospitalet and Section of Medical Statistics Joint work with P. Mostad, NR, B. Olaisen, B. Mevåg, M. Stenersen, Inst of Forensic Medicine.

2. 2 Innhold Bakgrunn: Utvikling av programmet Familias for rettsgenetiske beregninger 1994-2001 Metodisk bakgrunn. Demonstrasjon.

3. 3 Ambitions We would like to: - determine most likely family among many, - include non-DNA data (prior), e.g. age, - m odel mutations, - model kinship (departures from Hardy-Weinberg).

4. 4

5. 5 Bayesian solution Find a set of “possible” pedigrees Set up prior probabilities based on non-DNA information. Compute for each pedigree Make inferences from the posterior distribution:

6. 6 H 1 : M1 father H 2 : Unknown man father Posterior probability A,AB,B A,B M1 F1 M2 P(H 1 |data)= Flat prior

7. 7

8. 8 Prior distribution

9. 9 Modelling mutations Mutation rate varies with –Sex of parent and locus. Alleles tend to mutate to close alleles:

10. 10 Kinship and uncertainty in allele frequencies Vector of allele frequencies p Dirichlet by evolutionary argument data|p ~ Multinomial Then p|data ~ Dirichlet Basis for simulation

11. 11 Kinshipparameter 0.02. Ped 2, mest sannsynlige, svarer til tidligere figur

12. 12 Literature Evett og Weir. "Interpreting DNA evidence". Sinauer, MA, USA, 1998. http://www.nr.no/familias Egeland, Mostad, Mevåg og Stenersen. "Beyond traditional paternity and identification cases. Selecting the most probable pedigree". Forensic Science International, 110(1), 2000 Egeland and Mostad. SJS, 2002.