Comparison of two Multiplex Systems in Calculation Kinship among Close Relatives
This study compares the results obtained using multiplex systems PowerPlex® 16 and PowerPlex® Fusion to evaluate the probability of a full kinship (siblings), first cousin and half- sibling relationships among the offspring of three pairs of monozygotic twins. Genomic DNA was isolated and amplified from buccal swab ; selected short tandem repeat (STR) markers were detected. Electropherograms were generated and analyzed using the two multiplex systems for all subjects. Paternity testing for every nine offspring of six couples was performed and in all cases the probability that the alleged father was the true father, was over 99.9999%. Kinship analyses were performed setting up two hypotheses, where the relationships of full kinship, first cousins and half-siblings were tested and calculating the likelihood ratio (LR). Relatedness coefficients were used to describe the type of relationship between two subjects under the hypothesis and average likelihood ratios values showed which of the subjects had a higher percentage of common alleles. Determining the degree of relationship between subjects who were full siblings, the likelihood ratios were highest compared with the other two types of kinship. Kinship analyses between first cousins showed higher probabilities than when the subjects were half- siblings, rather than first cousins. Introduction of an additional seven loci used in the PowerPlex® Fusion System gave even higher average likelihood ratios and higher probabilities of these relations.