Evaluation of Genetic Markers in a Novel Diagnostic Strategy for Trisomy Based on Short Tandem Repeats / 现代生物医学进展

ABSTRACT

Background:In the newly published article,we presented a novel STR-based diagnostic strategy for trisomy.When applying the strategy to the detection of the copy number of the selected chromosome,it is necessary at first to construct a multi-marker diagnostic system for trisomy by selecting the optimal chromosome-specific STR markers from numerous STR polymorphisms in human genome.Objective:Attempting to provide a reliable method for selecting optimal STR markers to construct a diagnositic system of high efficiency,in this study,we further described the quantitative evaluation of single STR marker and multimarker system during the marker selection.Methods:We deduced the formulae of three-allele detection rae(TDR)and the probability that three different alleles are observed in a diagnostic system.(P),by which we can quantitatively evaluate efficacy of a STR marker and cumulative efficacy of a multi-marker diagnostic system.Furthermore,we applied them to a multi-marker diagnostic system for trisomy 21 which was constructed in the previous study.Results:The TDR values of nine STR markers in our diagnostic system for trisomy 21 ranged from 0.203 to 0.638.The probability that three different alleles are observed in the system is above 0.95.Conclusion:The numerical values obtained from the formulae can provide a basis for the selection of optimal STR markers and the determination of the number of STR markers needed in a system with high efficacy.