Laser Capture Microdissection Separate Horionic Villi Of Early Abortion Materials And Realize Paternity Testing

Objective:Finding and extraction of forensic biological evidence atthe scene of the crime are important which are the key of subsequent labtests.Extracting and testing of mixed, trace biological materials expand thescene of the crime detection and exploit the value all kinds of cases. As inforensic science laboratory DNA-based paternity testing is commonlyperformed after suspicious death or known homicide of pregnant women toprovide information useful to identification of possible suspects. theconcurrent presence of abundant maternal tissue will be preferentialamplification of excess maternal DNA often prevents detection of fetalgenotypes.The occurrence of mixed extracts with the potential to interferewith STR analysis is frequent and fetal DNA typing may even beimpossible when chorionic villi are rare amid maternal tissue.In our studythrough laser capture microdissection capturing cells of chorionic villi,fetal and maternal cells will be separated. Low volume-polymerase chain reaction was performed and paternity testing was realized.Method:LCM was combined with the AmpliGrid LV-PCR system toselect and detect chorionic villi. Cells of chorionic villi were setted thenumber of gradient cells20,30,40. PCR amplification of1.5μ L systemwas performed.3130XL Genetic Analyzer was obtained embryonicgenotype. The artificial alleles, detection rate and allelic dropout rate ofeach group were compared. The technology was applied into two actualcases.Result:The detection rate of40cells is high,allelic dropout rate andartifical alleles are low. The detection rate of20cells is low,allelic dropoutrate and artifical alleles are high.Conclusion: Cell separation technique can be applied to tissuesections of paraffin-embedded which accurately separate and test mixtureof fetus and maternal tissue. Objective: Frozen and paraffin sections can be used for the LCM, butparaffin sections may damage the structure of nucleic acid. Capturing lesscells are often difficult to get the big pieces of DNA. Frozen tissuerelatively preserved the integrity of the protein and nucleic acid, throughcapturing less cells can obtain DNA profile.To establish a technology platform, using single-cell separation technique and LCM to realizeaccurate separation and testing fetal and maternal tissue in mixture ofsamples.Method:Frozen section slides were prepared, setting the number ofgradient cells10,20,30. PCR amplification of1.5μ L system wasperformed.3130XL Genetic Analyzer was obtained embryonic genotype.Then the artificial alleles, detection rate and allelic dropout rate of eachgroup were compared. The technology was applied into two Simulationcases.Result:Capturing10cells of villus can obtain the fetal STR-DNAtype. The detection rate of30cells is high. Artificial alleles and allelicdropout rate are low. The detection rate of10cells is low,allelic dropoutrate and artifical alleles are high.Conclusion: Single-cell separation technique combined with LCMcan be applied to accurately separate and test mixture of fetal and maternaltissue, so as to improve evidence value of mixed biological samples.