[A new method for calculating paternity index].
OBJECTIVE
To introduce a new method for calculating the paternity index (PI).


METHODS
Assuming that each allele from parents has undergone a transition before it segregates and transmits to child. The transition probability is 1 when parent allele is the same as child's, the transition probability is 0 when parent allele is different from the child's. Every allele has a transmission probability with 0.5. Base on these theories, it is easy to gain the probability that child inherits an allele from the alleged father or mother. Thus, the X value (numerator) and Y value (denominator) of PI formula can be calculated, as unknown man provide an allele for child with the allele frequency.


RESULTS
A general formula that calculated the PI for trios, duos and missing child cases was deduced.


CONCLUSIONS
The new method is practical in all kinds of forensic paternity case.
Department of Forensic Biology, Zhongshan Medical College of Sun Yat-sen University, Guangzhou 510089, China. lvdejian@mail.sysu.edu.cn
De-Jian
DJ
Lü
Hui-Ling
HL
Lu
D000465:Algorithms; D000483:Alleles; D002648:Child; D005260:Female; D053803:Forensic Genetics; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D010287:Parent-Child Relations; D010334:Paternity