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How TrueAllele® Works (Part 3)Kinship, Paternity and Missing Persons
Cybergenetics WebinarCybergenetics WebinarDecember, 2014December, 2014
Mark W Perlin, PhD, MD, PhD Mark W Perlin, PhD, MD, PhD Cybergenetics, Pittsburgh, PACybergenetics, Pittsburgh, PA
Cybergenetics © 2003-2014Cybergenetics © 2003-2014
Kinship
Task. Infer genotypes and match them
Tool. Bayes theorem
Data. Genotypes of family members
Bayes theorem
child1 child2 child3
Pedigree
person spouse
father mother
X S
F M
C1 C2 C3
Prior probability
X
F M
person
father mother
aa ab
How a variable is affected
Prior probability
person
father mother
X
F M
aa bc
b c
a ab ac
a ab ac
ab1/2
ac1/2
X =
Punnett square
Likelihood
child
person spouse
X S
C
ab
bb
How a variable affects others
Likelihood
child
person spouse
X S
C
ab
bbaaaaaa
Posterior probability
person
father mother
X S
F M
C
aa bc
ab
bbchild
spouse
Posterior probability
person
father mother
X S
F M
C
aa bc
ab
bbchild
spouse
Genotype comparison
person
father mother
X S
F M
C
aa bc
ab
bbchild
spouse
A
allegedperson
ab
Bayes theorem, second round
Hypothesis: The missing and reference
persons are the same individual
Posterior to prior genotype probability ratio (Essen-Moller, 1938).
Match strength
child
Paternity
biologicalfather
X S
C
spouse
Paternity genotypeD7S820
Genotype comparison
X S
C
A
allegedfather
biologicalfather
child
spouse
Paternity index
LR = 3.28log(LR) = 0.52
10,10
Paternity
LR = 258,000log(LR) = 5.41
Maternity question
child
X
C
A1
allegedmothers
A2
A3
A4
A5
A6
biologicalmother
Biological mother genotype
child
X
C
biologicalmother
Identifying the mother
A1
A2
A3
A4
A5
A6
Missing person
child1 child2 child3
person
X
C1 C2 C3
1
1+2
1+2+3
Children + Spouse
person spouse
X S
C1 C2 C3
child1 child2 child3
1
1+2
1+2+3
Parents + Children
person
father mother
X
F M
C1 C2 C3
child1 child2 child3
1
1+2
1+2+3
Parents + Children + Spouse
person spouse
X S
F M
C1 C2 C3
child1 child2 child3
father mother 1
1+2
1+2+3
DNA mixture
Mixture + Kinship
person
father
X
F
Mixture + Kinship genotypesCSF1PO
Separated minor contributor
Kinship inferred sonRandom person
Contributor genotype match
mixture kinship
population
LR = 39,700log(LR) = 4.60
-18.00-20.58-20.66-20.76-22.00-24.00-24.00-24.97-26.00-28.00
How TrueAllele Works
http://www.cybgen.com/information/webinar/page.shtml
Part 1, 16-Oct-2014Genotype modeling and the likelihood ratio
Part 2, 20-Nov-2014Degraded DNA and allele dropout
Part 3, 18-Dec-2014Kinship, paternity and missing persons
Part 4, 15-Jan-2015Genotype database and DNA investigation
