Method for obtaining target nucleic acid form mixed nucleic acid

Abstract

The invention discloses a method for obtaining a lot of target nucleic acids form mixed nucleic acid, the mixed nucleic acid comprises the target nucleic acid and non-target nucleic acid. The method comprises the following steps: gathering the target nucleic acid from the mixed nucleic acid, wherein the gathering means usage of methyl binding domain protein for binding the non-target nucleic acid, removing a formed methyl binding domain protein- non-target nucleic acid bonder; amplifying the enriched target nucleic acid, wherein the amplifying means usage of a N6 random primer; wherein, a lot of target nucleic acids means that the target nucleic acid amount reaches a minimum nucleic acid amount which exceeds sequencing requirement, and the N6 random primer is a sequence with the length being 6 bp combined by A,T,C and G with random arrangement. The invention also discloses a method for identifying low-abundance strain in an anthropogenic genome sample.

Description

technical field [0001] The present invention relates to the field of biological sample processing, specifically, the present invention relates to a method for obtaining a large number of target nucleic acids from mixed nucleic acids, and a method for identifying low-abundance bacterial species in human metagenomic samples. Background technique [0002] Metagenome (meta for short), also known as microbial environmental genome or metagenome, is defined as the sum of the genetic material of all tiny organisms in a specific environment, which includes the genomes of all species in the microbial community. [0003] Human metagenomic samples (human metagenomic samples), such as nucleic acid samples from human skin, feces, saliva, etc., contain a small amount of microbial nucleic acid, and the main bacterial species in human meta samples from different sources Different, the abundance of some strains is extremely low, it is difficult to obtain effective amplification, and it is dif...

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Problems solved by technology

[0003] Human metagenomic samples (human metagenomic samples), such as nucleic acid samples from human skin, feces, saliva, etc., contain a small amount of microbial nucleic acid, and the main bacterial species in human meta samples from different sources Different, the abundance of some strains is extremely low, it is difficult to obtain effective amplification, and it is difficult to be detected

[0004] The host DNA accounts for the vast majority of trace human meta samples. For the sequencing analysis of human meta samples, the macrogene library sequencing technology is used to analyze the low-abundance bacterial species in trace low-abundance human meta samples. Previously The strategy is to extract the host DNA from the mixed nucleic acid sequencing data. For trace and low-abundance samples, this strategy has the problems of wasting data, high cost, and difficult analysis of low-abundance microorganisms.

Moreover, when constructing a sequencing library, the success rate of library construction is very low because the amount of initial nucleic acid in the sample is too low, and even if the constructed sequencing library meets the requirements of the machine, generally only in the background of routine related sample research based on experience during sequencing. On the basis of increasing the sequencing depth to obtain a large amount of sequencing data, and then using bioinformatics analysis technology to analyze the sequences from low-abundance bacteria contained in the sequencing data, the sequencing cost is high, and due to the large amount of data, the analysis workload is heavy

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