If one of the unknowns is related to one of the profiled known contributors...

[marlen...@gmail.com]

Hi Hinda,

As a beginner in using LRmix Studio I would like to ask you some questions.

I have a case where the victim is (identified as 1212/P1) and two suspects (designated 1212/P2 and 1212/P3). Suspects are related - father/son. The evidence is the suspect's clothes and the tools they use. The court wants to know if there is blood on the matter (determine the DNA profile) and who the blood comes from (whether 1212/P1 or 1212/P2 or 1212/P3).

I have difficulty in establishing hypotheses and my questions:

1. if I have a mixture of DNA from two people - a sample taken from blood stains from a sweater belonging to 1212/P2, where alleles are from victim-1212/P1 (drop-out=0) and 1212/P2 (drop-out=0.1) it's Hp: victim(1212/P1)+1212/P2; Hd: two unknown contributors

- Should I choose a relationship in the program?

- Should I mark in Hd 1212/P2 (the owner of the sweater?) Then the hypothesis Hd: 1212/P2+one unknown contributor?

- Should I select these two steps at a time or just only choose a relationship?

2. if I have a mixture of DNA from two people - a sample taken from blood stains from a sweater belonging to 1212/P2, where alleles are from 1212/P2 (drop-out=0) and 1212/P3 (drop-out=0.1) it's Hp: 1212/P2+1212/P3; Hd: two unknown contributors

- Should I choose a relationship in the program? If so, do I choose whether one of the unknown contributors is a relative of 1212/P2 or 1212/P3

- Should I mark in Hd 1212/P2 (the owner of the sweater?) Then the hypothesis Hd: 1212/P2+one unknown contributor?

- Should I select these two steps at a time or just only choose a relationship?

3. if I have a mixture of DNA from three people - a sample taken from blood stains from a sweater belonging to 1212/P2, where alleles are from victim-1212/P1 (drop-out=0.1) and 1212/P2 (drop-out=0.1) and 1212/P3 (drop-out=0.1) it's Hp: victim(1212/P1)+1212/P2+1212/P3; Hd: three unknown contributors

- Should I choose a relationship in the program? If so, do I choose whether one of the unknown contributors is a relative of 1212/P2 or 1212/P3

- Should I mark in Hd 1212/P2 (the owner of the sweater?) Then the hypothesis Hd: 1212/P2+two unknown contributors?

- Should I select these two steps at a time or just only choose a relationship?

4. Is it always in the hypothesis to calculate all known contributors (victim + suspected)? If I coompute simultaneously for all contributors then LR is very high..or should I compute each one separately?

I have too little experience with the program so I ask for your help.

Thank you very much for your answer.

Marlena.