Single-chain molecular identifier adapter and single-chain DNA database creating method and application thereof to circulating tumor DNA detection

Abstract

The invention discloses a single-chain molecular identifier adapter and a single-chain DNA database creating method and application thereof to circulating tumor DNA detection. The single-chain molecular identifier adapter comprises a stem structure formed by 14 base pairing, a sequencing primer sequence and a molecular identifier sequence formed by 8 random nucleotides, wherein a base 'U' is inserted between the sequencing primer sequence and a stem structure sequence, and a stem-loop structure can be formed by annealing denaturation of the single-chain nucleotide sequence. By single-chain DNAdatabase creating, technical problems of low sensitivity, fragmentation, low concentration and short ctDNA fragments in liquid biopsy in application of an existing detection technique are solved. Accurately distinguishing whether sequencing reads identical in genome coordinate beginning and end loci come from cfDNA released by the same one or multiple germinal cell is realized, sequencing reads derived from original positive and negative chains of the same cell are paired for analysis, and accordingly sequencing rehandling is reduced, and the distinguishing rate of false positive mutation isincreased.

Description

technical field [0001] The invention relates to the technical field of biomedicine, in particular to a single-strand molecular tag adapter, a method for building a single-strand DNA library and their application in detecting circulating tumor DNA. Background technique [0002] Plasma free DNA, also known as cfDNA (cell free DNA), refers to the free extracellular DNA in the periphery. The source of cfDNA includes both normal cells and abnormal cells (such as tumor cells) or exogenous microorganisms (such as viral DNA). Specifically, it includes apoptotic bodies from normal cell metabolism, tumor cell fragments, exosomes, etc. [0003] Circulating tumor DNA (ctDNA) refers to the DNA that contains a variety of cancer-related mutations in the peripheral circulating blood, mainly released by tumor cells after shedding or apoptosis and entering the circulatory system. ctDNA comes from the tumor cells themselves, and is a highly sensitive and specific characteristic tumor biomarke...

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Problems solved by technology

[0010] In order to solve the deficiencies in the prior art, the purpose of the present invention is to provide a single-stranded molecular tag adapter and a method for building a single-stranded DNA library and its application in detecting circulating tumor DNA. In the detection technology, there are technical problems in liquid biopsy, especially the short, low concentration, fragmentation, and low sensitivity of ctDNA fragments; secondly, based on the molecular labeling technology and the characteristics of single-strand library construction, it is possible to accurately identify the sequencing reads with the same genome coordinates from the beginning and end of the site. The cfDNA released by the same or multiple original cells, and the purpose of pairing the sequencing reads of the original positive and negative strands from the same cell, thereby reducing sequencing duplication and improving the resolution of false positive mutations

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