[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.
Lü
De-Jian
DJ
Department of Forensic Biology, Zhongshan Medical College of Sun Yat-sen University, Guangzhou 510089, China. lvdejian@mail.sysu.edu.cn
Lu
Hui-Ling
HL
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