A novel strategy for sibship determination in trio sibling model

Abstract

AimTo use a virtually simulated population, generated from published allele frequencies based on 15 short tandem repeats (STR), to evaluate the efficacy of trio sibship testing and sibling assignment for forensic purposes.MethodsVirtual populations were generated using 15 STR loci to create a large number of related and unrelated genotypes (10 000 trio combinations). Using these virtual populations, the probability of related and unrelated profiles can be compared to determine the chance of inclusions of being siblings if they are true siblings and the chance of inclusion if they are unrelated. Two specific relationships were tested – two reference siblings were compared to a third true sibling (3S trio, sibling trio) and two reference siblings were compared to an unrelated individual (2S1U trio, non-sibling trio).ResultsWhen the likelihood ratio was greater than 1, 99.87% of siblings in the 3S trio population were considered as siblings (sensitivity); 99.88% of non-siblings in the 2S1U trio population were considered as non-siblings (specificity); 99.9% of both populations were identified correctly as siblings and non-siblings; and the accuracy of the test was 99.88%.ConclusionsThe high sensitivity and specificity figures when using two known siblings compared to a putative sibling are significantly greater than when using only one known relative. The data also support the use of increasing number of loci allowing for greater confidence in genetic identification. The system established in this study could be used as the model for evaluating and simulating the cases with multiple relatives.

Sibship Analysis Based on Parental Genotype Reconstruction from Any Number of Reference Siblings

“…Formulations for the set of two‐person pedigrees for full‐siblings and half‐siblings (the set of pedigrees for half‐siblings, grandparent–grandchild relationships, and avuncular relationships belong to the joint genotypic probabilities ) have all been derived to test only two allegedly related individuals. However, in 2012, Lee et al performed a study of two “reference” siblings and an alleged “test” sibling. In practical forensic applications, the relationship determination is not limited to a test individual and a single reference individual; rather, in certain cases, an alleged individual may be compared with more than one sib or uncle.…”

The risk of false inclusion of a relative in parentage testing – an in silico population study

“…Evaluation of the efficacy of trio sibship testing and sibling assignment for forensic purposes by using such model populations was performed in our laboratory (11). In this study, we report on the false paternity probabilities with 15 STR loci when comparing two close genetic relatives (two siblings, paternal grandparent/grandchild, paternal uncle/nephew or niece, two half siblings, and two cousins) and two random persons.…”