### Abstract

Likelihood ratios (LRs) were calculated for a cohort of 60 pairs of true half-sibs and compared with LR values calculated for unrelated, paired children. STR results for the half-sib group were obtained from 60 archived cases involving a true mother, two children, and an alleged father subjected to typing with a multiplex STR kit (Identifiler multiplex, Applied Biosystems) and in which the alleged father was excluded as the father of only one of the two children (half-sib pairs). The distribution of LR values among true half-sibs was compared to those produced from paired, unrelated children selected in two ways: One method for producing unrelated pairs was to randomly select Identifiler profiles from children in 120 distinct paternity cases and group them into 60 ethnically matched pairs (random pairs). In a second approach, the children in the true half-sib group were shuffled and ultimately paired with someone from a different case. A total of 49 ethnically matched, unrelated pairs were created (shuffled pairs). In the shuffled pairs group, comparisons were thus based on a constant set of phenotypes. LRs comparing the probability of half-sibship versus being unrelated were produced for all groups with standard methods. Among pairs of known half-sibs, LRs ranged from a low of 0.1 to a maximum of 3763. Among random and shuffled pairs, LRs ranged from a low of 0.0001 to 12 for shuffled pairs or 42 for random pairs. LRs of greater than 2 were produced in 8 instances among random pairs and in 4 instances among the shuffled pairs. Overall, results suggest that half-sib indices of 30 or greater are fairly characteristic of individuals who are related as half-sibs. In contrast, half-sib indices of 0.1 or less are fairly characteristic of unrelated individuals who claim to be half-sibs. LRs falling between 0.1 and 10.0 are uninformative, as this region represents the overlap in the LR distributions produced from the true and false half-sib groups when the Identifiler multiplex kit is used for testing.

Original language | English |
---|---|

Pages (from-to) | 515-519 |

Number of pages | 5 |

Journal | Transfusion |

Volume | 47 |

Issue number | 3 |

DOIs | |

State | Published - 1 Mar 2007 |

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*Transfusion*,

*47*(3), 515-519. https://doi.org/10.1111/j.1537-2995.2006.01144.x

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*Transfusion*, vol. 47, no. 3, pp. 515-519. https://doi.org/10.1111/j.1537-2995.2006.01144.x

**Considerations for the interpretation of STR results in cases of questioned half-sibship.** / Allen, Robert W.; Fu, Jun; Reid, Thomas M.; Baird, Michael.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Considerations for the interpretation of STR results in cases of questioned half-sibship

AU - Allen, Robert W.

AU - Fu, Jun

AU - Reid, Thomas M.

AU - Baird, Michael

PY - 2007/3/1

Y1 - 2007/3/1

N2 - Likelihood ratios (LRs) were calculated for a cohort of 60 pairs of true half-sibs and compared with LR values calculated for unrelated, paired children. STR results for the half-sib group were obtained from 60 archived cases involving a true mother, two children, and an alleged father subjected to typing with a multiplex STR kit (Identifiler multiplex, Applied Biosystems) and in which the alleged father was excluded as the father of only one of the two children (half-sib pairs). The distribution of LR values among true half-sibs was compared to those produced from paired, unrelated children selected in two ways: One method for producing unrelated pairs was to randomly select Identifiler profiles from children in 120 distinct paternity cases and group them into 60 ethnically matched pairs (random pairs). In a second approach, the children in the true half-sib group were shuffled and ultimately paired with someone from a different case. A total of 49 ethnically matched, unrelated pairs were created (shuffled pairs). In the shuffled pairs group, comparisons were thus based on a constant set of phenotypes. LRs comparing the probability of half-sibship versus being unrelated were produced for all groups with standard methods. Among pairs of known half-sibs, LRs ranged from a low of 0.1 to a maximum of 3763. Among random and shuffled pairs, LRs ranged from a low of 0.0001 to 12 for shuffled pairs or 42 for random pairs. LRs of greater than 2 were produced in 8 instances among random pairs and in 4 instances among the shuffled pairs. Overall, results suggest that half-sib indices of 30 or greater are fairly characteristic of individuals who are related as half-sibs. In contrast, half-sib indices of 0.1 or less are fairly characteristic of unrelated individuals who claim to be half-sibs. LRs falling between 0.1 and 10.0 are uninformative, as this region represents the overlap in the LR distributions produced from the true and false half-sib groups when the Identifiler multiplex kit is used for testing.

AB - Likelihood ratios (LRs) were calculated for a cohort of 60 pairs of true half-sibs and compared with LR values calculated for unrelated, paired children. STR results for the half-sib group were obtained from 60 archived cases involving a true mother, two children, and an alleged father subjected to typing with a multiplex STR kit (Identifiler multiplex, Applied Biosystems) and in which the alleged father was excluded as the father of only one of the two children (half-sib pairs). The distribution of LR values among true half-sibs was compared to those produced from paired, unrelated children selected in two ways: One method for producing unrelated pairs was to randomly select Identifiler profiles from children in 120 distinct paternity cases and group them into 60 ethnically matched pairs (random pairs). In a second approach, the children in the true half-sib group were shuffled and ultimately paired with someone from a different case. A total of 49 ethnically matched, unrelated pairs were created (shuffled pairs). In the shuffled pairs group, comparisons were thus based on a constant set of phenotypes. LRs comparing the probability of half-sibship versus being unrelated were produced for all groups with standard methods. Among pairs of known half-sibs, LRs ranged from a low of 0.1 to a maximum of 3763. Among random and shuffled pairs, LRs ranged from a low of 0.0001 to 12 for shuffled pairs or 42 for random pairs. LRs of greater than 2 were produced in 8 instances among random pairs and in 4 instances among the shuffled pairs. Overall, results suggest that half-sib indices of 30 or greater are fairly characteristic of individuals who are related as half-sibs. In contrast, half-sib indices of 0.1 or less are fairly characteristic of unrelated individuals who claim to be half-sibs. LRs falling between 0.1 and 10.0 are uninformative, as this region represents the overlap in the LR distributions produced from the true and false half-sib groups when the Identifiler multiplex kit is used for testing.

UR - http://www.scopus.com/inward/record.url?scp=33847028647&partnerID=8YFLogxK

U2 - 10.1111/j.1537-2995.2006.01144.x

DO - 10.1111/j.1537-2995.2006.01144.x

M3 - Article

C2 - 17319834

AN - SCOPUS:33847028647

VL - 47

SP - 515

EP - 519

JO - Transfusion

JF - Transfusion

SN - 0041-1132

IS - 3

ER -