Plasma cfDNA (cell-free deoxyribonucleic acid) bi-molecular marker, method for marking and detecting plasma cfDNA and application of plasma cfDNA bi-molecular marker

Abstract

The invention provides a plasma cfDNA (cell-free deoxyribonucleic acid) bi-molecular marker. The bi-molecular marker is oligonucleotide, the sequence is represented as follows: a) 5'P-GACGTC-GATCGGAAGAGCTCGTATGCCGTCTTCTGCTTG, b) 5' ACACTCTTTCCCTACACGACGCTCTTCCGATCT-NNNNNNNNNNNNNNNNNNNN-GACGTCT, the sequence of oligonucleotide is from the 5' terminal to the 3' terminal from left to right, N represents a random basic group, and P represents a phosphate group; the oligonucleotide sequence is synthesized artificially. The plasma cfDNA bi-molecular marker is used for distinguishing every plasma cfDNA molecule by adding a unique molecular marker to every plasma cfDNA molecule and can be applied to plasma cfDNA detection. The plasma cfDNA bi-molecular marker overcomes defects of cfDNA detection with a conventional NGS (next generation sequencing) technology, and specifically has following technical effects: 1), the cfDNA valid data volume in a database construction process is increased; 2), noise signals such as deviation and detection errors produced in intermediate steps of gene detection can be reduced; 3), target variation can be effectively detected, meanwhile, low false positive rate is realized, and accuracy and stability of gene detection are improved.

Description

technical field [0001] The invention relates to a plasma free DNA bimolecular label, a method for labeling plasma cfNDA and an application thereof, belonging to the field of biotechnology. Background technique [0002] There is free deoxyribonucleic acid in plasma without cell structure, which is called cell free DNA (cfDNA) [ChanKC, YeungSW, LuiWB, RainerTH, LoYM. Effects of preanalytical factors on the molecular size of cell-free DNA in blood. ClinChem. 2005Apr; 781-4]. cfDNA is a complex mixture, most of which come from ruptured blood cells or vascular endothelial cells in blood, and a small part comes from apoptotic placental cells or necrotic tumor cells. By detecting a small amount of placental DNA or tumor DNA in cfDNA, it is possible to detect the genetic characteristics of embryos and tumors without invading embryos and obtaining tumor biopsies [Lo, Y.M., Corbetta, N., Chamberlain, P.F., et al. ( 1997)PresenceoffetalDNAinmaternalplasmaandserum.Lancet350,485–487.AN...

AI Technical Summary

Problems solved by technology

When the proportion of fetal or tumor gene mutations is similar to the proportion of NGS sequencing errors, it is impossible to accurately determine whether the test results are real gene mutations or sequencing errors

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