Evaluation of Detection Efficiency for Trio Full Sibling Testing

Objective To study the detection efficiency of trio full sibling with another known full sibling reference added under different number of autosomal STR typing systems. Methods Based on 43 detection systems consisting of 13 to 55 representative autosomal STR loci，10 000 true families （full sibling group） and 10 000 false families （unrelated individual group） were randomly simulated. The full sibling index （FSI） was calculated based on the method of family reconstruction. The cumulative sibling relationship index （CFSI） of 0.000 1 and 10 000 were used as the evaluation thresholds, and the detection efficiency parameters were calculated and compared with the identification of the duo full sibling testing. Results With the increasing number of STR loci， the error rate and inability of judgement rate gradually decreased; the sensitivity， specificity, correct rate of judgment and other parameters gradually increased, and the system efficiency gradually improved. Under the same detection system， trio full sibling testing showed higher sensitivity， specificity， system efficiency and lower inability of judgement rate compared with duo full sibling testing. When the system efficiency was higher than 0.85 and inability of judgement rate was less than 0.01%， at least 20 STRs should be detected for trio full sibling testing， which was less than 29 STRs required by duo full sibling testing. Conclusion The detection efficiency of trio full sibling testing is superior to that of duo full sibling testing with the same detection system， which is an effective identification scheme for laboratories with inadequate detection systems or for materials with limited conditions.