法医DNA遗传分析仪毛细管间信号串扰的研究

Avoidance against Occurring Signal Crosstalk between Capillaries of Forensic DNA Genetic Analyzer

目的毛细管电泳是STR分型检验的主要技术手段,但多道毛细管的法医DNA遗传分析仪毛细管间有时会出现信号串扰,需要对此进行研究和分析应对。方法以具有24道毛细管的3500xL遗传分析仪为例,实验组:每次电泳,选择1个毛细管泳道对阳性样本的过量扩增产物进行电泳,1个毛细管泳道对等位基因Ladder进行电泳,其余22个毛细管泳道全部对空白对照进行电泳;对照组:选择1个毛细管泳道对等位基因Ladder进行电泳,其余23个毛细管泳道全部对空白对照进行电泳。结果过量阳性样本电泳时,其相邻的含空白样本的毛细管可以检测到峰值较低的串扰信号;去除阳性样本后,串扰信号消失。结论STR分型毛细管电泳检测过程中,相邻毛细管间可能会发生信号串扰。毛细管内的电泳样本过载时,相邻的空白样本或低浓度样本所在的毛细管可能会检测到峰值较低的串扰信号。荧光接收相关硬件的故障、空间校准的失败也有可能导致毛细管间低峰值串扰信号的产生。

Objective To analyze the signal crosstalk occurring between the capillaries of lane-multiple forensic DNA genetic analyzer.Methods The 3500xL genetic analyzer installed of 24 lane-capillaries was chosen to conduct the capillary electrophoretic experiments,having being carried out of two-group test with the experimental group:one capillary lane being selected for overloading the amplification products of an STR-profile-positive sample and one capillary lane for loading the allele ladder,with the rest 22 capillary lanes being filled of only the blank reagent without samples;and the control group:one capillary lane chosen for the allele ladder to load and the remaining 23 capillary lanes being full of the blank reagent.Results For the experimental group,the crosstalk signals were detected with height-low peaks appearing in the adjacent capillary lanes where such peaks should otherwise not have emerged since only the blank reagent existed there.For the control group,no crosstalk signals were observed.Conclusions Signal crosstalk may occur between the immediately-connecting capillary lanes during the capillary electrophoresis of PCR-amplified products to have their STR genotypes profiled.Overloading is the major cause of such phenomena.When a sample is overloaded into a capillary lane,crosstalk signals will likely be detected with height-low peaks appearing in the adjacent capillary lanes where if blank or low-concentration samples were added.The signal crosstalk may also result from the analyzer’s hardware spatial malfunction or calibration failure.