阅读说明：本技术 构建dna文库的方法及其应用 (Method for constructing DNA library and application thereof ) 是由 陈晓丹 徐护朝 潘伟业 李志民 李大为 玄兆伶 王海良 王娟 于 2019-08-12 设计创作，主要内容包括：本发明公开了构建DNA文库的方法及其应用。其中,该构建DNA文库的方法包括：提供嵌合标记物的DNA,其中,所述嵌合标记物的DNA具有三维结构信息；将所述嵌合标记物的DNA进行转座处理,以便得到转座产物；对所述转座产物进行捕获处理,以便得到捕获后的DNA；以及将所述捕获后的DNA进行扩增处理,以便获得所述DNA文库。该建库方法步骤简单,耗时短,尤其适用于痕量DNA样本的文库构建,并且测序的有效数据比例高,噪音单末端悬挂值低。(The invention discloses a method for constructing a DNA library and application thereof. Wherein, the method for constructing the DNA library comprises the following steps: providing DNA of a chimeric marker, wherein the DNA of the chimeric marker has three-dimensional structural information; subjecting the DNA of the chimeric marker to transposition treatment to obtain a transposition product; capturing the transposition product to obtain captured DNA; and subjecting the captured DNA to an amplification treatment so as to obtain the DNA library. The library construction method is simple in steps, short in time consumption, particularly suitable for library construction of trace DNA samples, high in sequencing effective data proportion and low in noise single-end hanging value.)

1. A method of constructing a DNA library comprising:

providing DNA of a chimeric marker, wherein the DNA of the chimeric marker has three-dimensional structural information;

subjecting the DNA of the chimeric marker to transposition treatment to obtain a transposition product;

capturing the transposition product to obtain captured DNA; and

subjecting the captured DNA to an amplification treatment to obtain the DNA library.

2. The method of claim 1, wherein the marker is biotin.

3. The method of claim 1, wherein the DNA of the chimeric marker comprises portions of spatially adjacent DNA segments.

4. The method of claim 1, wherein the method of obtaining the DNA of the chimeric marker comprises:

performing fixed cross-linking treatment on chromatin in cells to form a DNA-protein cross-linked substance;

performing enzyme digestion treatment on the DNA-protein cross-linked substance to generate a DNA-protein complex containing a sticky end; and

filling in the cohesive ends with nucleotides containing one or more of the labels, creating blunt ends and subsequently ligating the blunt ends together to form contiguously ligated genomic DNA.

5. The method as claimed in claim 1, wherein the transposition treatment is performed using a transposase.

6. The method of claim 4, wherein the transposase is Tn5 transposase.

7. The method as claimed in claim 4, wherein the ratio of DNA of the chimeric marker to the transposase is 10 ng: 50-100 nM.

8. The method as claimed in claim 4, wherein the transposition-treated reaction system comprises, based on 10ng of the DNA of the chimeric marker:

8-12. mu.l of transposition buffer;

0.2-1 μ L10% tween 20;

7-10 μ L of water; and

0.5-3. mu.l of the transposase.

9. The method as claimed in claim 4, wherein the transposition treatment is carried out at a temperature of 50 to 60 ℃ for 5 to 15 minutes.

10. Method according to claim 2, characterized in that the extraction process is a fishing process, preferably streptavidin magnetic beads,

optionally, the streptavidin magnetic beads are added in an amount of 5-10. mu.l, based on 1ng of the extracted DNA.

11. A method of obtaining chromatin interaction information in a cell of an individual, comprising:

using the method of constructing a DNA library of any one of claims 1-10, so as to obtain a DNA library of the individual; and

sequencing and analyzing the DNA library to obtain chromatin interaction information within the individual's cells.

12. A method of obtaining biometric information of an individual, comprising:

using the method of constructing a DNA library of any one of claims 1-10, so as to obtain a DNA library of the individual; and

sequencing and analyzing the DNA library to obtain the individual biological information.

13. A method for three-dimensional genome research, which is performed by the method for constructing a DNA library according to claims 1 to 10 or the method for obtaining chromatin interaction information in an individual cell according to claim 11 or the method for obtaining biological information of an individual according to claim 12.

14. A method for prenatal diagnosis or cancer screening, wherein the method is performed by the method for constructing a DNA library according to claims 1 to 10 or the method for obtaining chromatin interaction information in an individual according to claim 11 or the method for obtaining biological information of an individual according to claim 12 or the method for three-dimensional genome research according to claim 13.

15. A kit, comprising: the reagent, the primer, the mediating fragment or the combination of at least one of them used in the method for constructing a DNA library according to claims 1 to 10.

16. Use of the kit of claim 15 for three-dimensional genomic banking or prenatal diagnosis or cancer screening.

Technical Field

The invention relates to the field of biotechnology, in particular to a method for constructing a DNA library and application thereof, and more particularly relates to a method for constructing a DNA library, a method for obtaining chromatin interaction information in individual cells, a method for obtaining biological information of an individual, a three-dimensional genome research method, a prenatal diagnosis or cancer screening method, a kit and application of the kit in three-dimensional genome library construction or prenatal diagnosis or cancer screening.

Background

The existing second generation sequencing library construction technology has a plurality of steps, and especially, the loss of effective fragments is probably caused by multi-step operation before final end repair to PCR. The method is more remarkable in three-dimensional genome Hi-C library construction, and chimera DNA marked with biotin is relatively trace as a library construction template, so that the loss of effective fragments after fishing can directly influence the quality of the final library. And, the step of fragment screening, which is set up to make the library adaptable to the principle of sequencing by synthesis of illumina, but too long fragments result in poor quality sequencing data. At the same time, a considerable portion of the available library fragments can be screened for fragment length problems, especially in the case of nanogram-scale templates, which results in a reduction in the number of available libraries and directly affects the available data ratio.

Thus, existing library construction methods are in need of improvement.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, one objective of the present invention is to provide a method for constructing a DNA library, which introduces transposase during library construction, simplifies the steps of DNA fragmentation and linker addition, does not require end repair, adds base a at the 3' end, has short library construction time, has appropriate fragment length of library products, can directly perform computer sequencing without fragment screening, and has a high effective data ratio for sequencing.

It should be noted that the present invention is completed based on the following work of the inventors:

the inventors introduced transposase into the Hi-C pool. Because the transposase is provided with two sections of short nucleic acids, namely the joints suitable for the illunima sequencing, when the transposase randomly fragments DNA, the joints are connected to two ends of a small DNA segment at the same time, and then a library capable of sequencing can be obtained by using specific primer amplification, so that the library building process is obviously simplified, the library building time is shortened, and the effective data proportion of the Hi-C library is obviously improved.

Thus, according to a first aspect of the invention, there is provided a method of constructing a DNA library. According to an embodiment of the invention, the method comprises: providing inlays

DNA of a chimeric marker, wherein the DNA of the chimeric marker has three-dimensional structural information; subjecting the DNA of the chimeric marker to transposition treatment to obtain a transposition product; capturing the transposition product to obtain captured DNA; and subjecting the captured DNA to an amplification treatment so as to obtain the DNA library.

According to the method for constructing the DNA library, in the library construction process, particularly in the Hi-C library construction process, the steps of DNA fragmentation and linker addition are simplified through transposition treatment, the steps of end repair and base A addition at the 3' end are not needed, the library construction time is obviously shortened, the fragment length of a library product is proper, the direct machine sequencing can be carried out without fragment screening, the method is particularly suitable for constructing the Hi-C library of a trace DNA sample, the effective data proportion of the sequencing is high, and the single-end overhang noise value is low.

Further, based on the above-described method for constructing a DNA library, according to a second aspect of the present invention, there is provided a method for obtaining chromatin interaction information in an individual cell. According to an embodiment of the invention, the method comprises: using the method described previously, so as to obtain a DNA library of said individual; sequencing and analyzing the DNA library to obtain chromatin interaction information within the individual's cells. Therefore, the method for obtaining the chromatin interaction information in the individual cell has simplified steps and shortened operation time, is particularly suitable for constructing the Hi-C library of a trace DNA sample, has high sequencing effective data proportion and low noise single-terminal hanging value, and is favorable for the research in the field of three-dimensional genome. It should be noted that the method for constructing a DNA library has all the technical features and effects of the method for constructing a DNA library, and are not described in detail herein.

Further, based on the above-described method for constructing a DNA library, according to a third aspect of the present invention, there is provided a method for obtaining biological information of an individual. According to an embodiment of the invention, the method comprises: using the aforementioned method for constructing a DNA library so as to obtain a DNA library of the individual; sequencing and analyzing the DNA library to obtain the individual biological information. Therefore, the method for obtaining the individual biological information has simplified steps and shortened operation time, is particularly suitable for constructing the Hi-C library of a trace DNA sample, has high sequencing effective data proportion and low noise single-end hanging value, and is favorable for research and clinical diagnosis in the field of three-dimensional genomes. It should be noted that the method for constructing a DNA library has all the technical features and effects of the method for constructing a DNA library, and are not described in detail herein.

Further, according to a fourth aspect of the present invention, there is provided a three-dimensional genome research method. According to an embodiment of the present invention, the method is performed by the aforementioned method for constructing a DNA library or the aforementioned method for obtaining information on chromatin interaction in cells of an individual or the aforementioned method for obtaining biological information of an individual. Therefore, the steps of the method for constructing the DNA library and the method for obtaining the individual biological information are simplified, the operation time is shortened, the method is particularly suitable for constructing the library of trace DNA samples, the effective data ratio of sequencing is high, the noise daggling value is low, and the obtained biological information is suitable for three-dimensional genome research. It should be noted that the method for constructing a DNA library has all the technical features and effects of the method for constructing a DNA library, and are not described in detail herein.

Further, according to a fifth aspect of the invention, the invention provides a method of prenatal diagnosis or cancer screening. According to the rating of the present invention, the method is performed by the aforementioned method of constructing a DNA library or the aforementioned method of obtaining biological information of an individual or the aforementioned three-dimensional genome research method. Therefore, the steps of the method for constructing the DNA library and the method for obtaining the individual biological information are simplified, the operation time is shortened, the method is particularly suitable for constructing the library of the trace DNA sample, the effective data ratio of sequencing is high, the noise daggling value is low, and the obtained biological information is favorable for clinical diagnosis, particularly prenatal diagnosis and cancer screening. It should be noted that the method for constructing a DNA library has all the technical features and effects of the method for constructing a DNA library, and are not described in detail herein.

Further, according to a sixth aspect of the present invention, there is provided a kit comprising, according to an embodiment of the present invention: reagents, primers, mediation fragments, or a combination of at least one of them used in the aforementioned method for constructing a DNA library. Therefore, the method for constructing the DNA library by using the kit and the method for obtaining the chromatin interaction information and the biological information in the individual cell have the advantages of simplified steps, shortened operation time, high sequencing effective data proportion and low noise dangling value, are particularly suitable for constructing the library of trace DNA samples, and the obtained biological information is favorable for clinical diagnosis, particularly prenatal diagnosis and cancer screening. It should be noted that the kit has all the technical features and effects of the method for constructing a DNA library, and is not described herein again.

Further, according to a seventh aspect of the present invention, the present invention provides the use of the aforementioned kit in three-dimensional genomic banks or prenatal diagnosis or cancer screening. Therefore, the method for constructing the DNA library by using the kit and the method for obtaining the chromatin interaction information and the biological information in the individual cell have the advantages of simplified steps, shortened operation time, high sequencing effective data ratio, low noise dangling value, suitability for three-dimensional gene bank construction, and the obtained biological information which is favorable for clinical diagnosis, especially prenatal diagnosis and cancer screening.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 shows a schematic alignment of a process for constructing a DNA library according to one embodiment of the present invention;

FIG. 2 is a schematic diagram showing the principle of single-end overhang for Tn5 transposase noise removal data according to one embodiment of the present invention;

FIG. 3 shows a schematic diagram of quality-controlled agarose gel electrophoresis of a library cut according to one embodiment of the invention;

FIG. 4 shows a schematic diagram of a library Agilent HS2100 peak according to one embodiment of the present invention;

FIG. 5 shows a schematic representation of the library Agilent HS2100 peak according to a comparative example of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

It should be noted that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Further, in the description of the present invention, "a plurality" means two or more unless otherwise specified.

Method for constructing DNA library

According to a first aspect of the invention, the invention provides a method of constructing a DNA library. According to the method for constructing the DNA library, in the library construction process, particularly in the Hi-C library construction process, the steps of DNA fragmentation and linker addition are simplified through transposition treatment, the steps of end repair and base A addition at the 3' end are not needed, and the library construction time is remarkably shortened. In addition, the fragment length of the library product is appropriate, the sequencing can be directly carried out on the machine without fragment screening, the method is particularly suitable for Hi-C library construction of trace DNA samples, the effective data proportion of the sequencing is high, in some embodiments, the effective data proportion reaches more than 35%, the improvement is nearly 10% compared with the prior art, and the single-end hanging value of noise is low. In some embodiments, the null noise data has a single-ended overhang value of only 0.6%.

According to the method for constructing the DNA library, the steps of DNA fragmentation and joint adding are simplified through transposition treatment, and the transposition treatment does not act on the tail end of a small DNA fragment, so that the small fragment with biotin at the single-stranded tail end is not added with a joint, and further PCR reaction cannot be carried out, and the noise single-end hanging value of the Hi-C library is remarkably reduced or even removed.

According to the method for constructing the DNA library provided by the embodiment of the invention, the transposition treatment enables the DNA to be cut into small fragments of 200-500bp, and at the moment, the main peak of the fragment length of the library product after PCR is also within about 300-600bp, so that the DNA can be directly subjected to machine sequencing without fragment screening, and the experimental steps are further simplified.

According to the method for constructing the DNA library, provided by the embodiment of the invention, the experimental steps are simplified, the loss of samples in the experimental process is reduced, and the sample amount can be reduced to 10³Number of cells.

In order to facilitate understanding of the method for constructing a DNA library according to an embodiment of the present invention, the method is explained according to an embodiment of the present invention, and includes:

s100: providing DNA

According to an embodiment of the present invention, there is provided a DNA of a chimeric marker, wherein the DNA of the chimeric marker has three-dimensional structural information. Specifically, the library construction method provided by the embodiment of the invention constructs a Hi-C high-throughput sequencing library by using DNA of a chimeric marker with a three-dimensional structure, and researches the relation of chromatin DNA on a spatial position by using a high-throughput sequencing technology and combining a bioinformatics method; by capturing the DNA interaction mode, high-resolution chromatin three-dimensional structure information is obtained.

According to an embodiment of the invention, the marker is biotin. Therefore, the DNA is marked by biotin, and the subsequent fishing and purification of the DNA are facilitated.

According to an embodiment of the invention, the DNA of the chimeric marker contains portions of spatially adjacent DNA segments. That is, the DNA of the chimeric marker is not a continuous intact DNA fragment in chromatin within the nucleus of the protocell, but is chimeric by at least two spatially adjacent DNA segments. Furthermore, analysis of long-range chromatin interactions using proximity-ligation-based DNA interaction analysis and protein-specific DNA binding facilitates the definition of cis-regulatory element target genes and the annotation of the function of non-coding sequence variants associated with various physiological and pathological conditions for use in pathological studies of clinical disease, particularly the exploration of cancer mechanisms.

Specifically, according to an embodiment of the present invention, a method of obtaining the DNA of the chimeric marker includes: performing fixed cross-linking treatment on chromatin in cells to form a DNA-protein cross-linked substance; performing enzyme digestion treatment on the DNA-protein cross-linked substance to generate a DNA-protein complex containing a sticky end; filling the sticky ends with one or more biotin-label-containing nucleotides and biotin-free common nucleotides, creating blunt ends that are then ligated together to form contiguously ligated DNA that is genomic DNA if all chromatin within the cell is fixed; and (3) fragmenting the genome DNA to obtain the DNA of the chimeric marker.

S200: transposition treatment

According to the embodiment of the present invention, the DNA of the chimeric marker is subjected to transposition treatment to obtain a transposition product. Therefore, the DNA of the chimeric marker can be fragmented and added with the joint only by one-step transposition treatment, the steps of DNA fragmentation, end repair, 3' A addition, joint addition and the like in the prior art are replaced, the experimental process is obviously simplified, and the library building time is shortened.

According to the embodiment of the present invention, transposition treatment is performed using transposase. Here, the transposition process in the process of library construction is explained by taking Tn5 transposase as an example. In some embodiments of the invention, the Tn5 transposase used is Tn5 transposase reagent developed by Epicentre corporation, since transposase has two sections of short nucleic acids, it can be a linker for illunima sequencing for library construction, when transposase fragments DNA at random, linkers are simultaneously connected to both ends of the fragmented DNA fragments, and then specific primers are used for amplification to obtain a library which can be sequenced.

The inventor finds that transposase introduced in the Hi-C library construction process, particularly Tn5 transposase, has at least one of the following advantages:

first, simplified library construction procedure: the transposase, particularly Tn5 transposase, is used for constructing a library, steps of DNA fragmentation, end repair, 3' A adding, adaptor adding and the like in the prior art can be replaced, only one-step transposition treatment is needed, the DNA can be directly fragmented, the adaptor is added to the fragment, the length of the adaptor-added DNA fragment is proper, and the library can be obtained by direct PCR amplification. The comparison between the method for constructing the DNA library of the embodiment of the invention and the method for constructing the DNA library of the prior art is shown in FIG. 2, the experimental process of the invention is obviously simplified, and the library construction time is obviously shortened. According to the embodiment of the invention, after the DNA is extracted, the method of the embodiment of the invention can complete the rapid library building only in 3 hours.

Second, increase effective library ratio: in the existing Hi-C library construction process, an important reason for influencing the available data ratio is that the single-end overhang value of the noise value of the library is too high, the blunt-end ligation efficiency after biotin labeling is too low, DNA fragments of single-chain end labeled biotin which cause some ligation failures can be finally fished out by streptavidin magnetic beads, and the data account for too high, which indicates that the library construction efficiency is relatively low, and even causes the library construction failure. The nature of Tn5 transposase allows libraries to reduce the occurrence of single-end overhangs, in that Tn5 does not act on ends of DNA fragments that are too short in length, e.g., DNA fragments less than 200bp in length, so that small fragments of DNA with biotin at the single-stranded end are not ligated and PCR reactions are not allowed to proceed. While the small fragment with linker but no biotin tag in the middle, was used for normal PCR but could not be captured by streptavidin beads, as shown in FIG. 3. Thus, the noise single-end overhang value of the Hi-C library can be significantly reduced or even eliminated by utilizing the characteristics of the Tn5 transposase. According to the embodiment of the invention, the effective data proportion is improved by about 10%.

Third, fragment screening of the library was not performed: the Tn5 transposase property can make DNA cut into 200-500bp small fragments, at this time, the main peak of the length of the PCR library product fragment is also within about 300-600bp, and the DNA can be directly sequenced on the machine without fragment screening, and fragmentation treatment is not needed, thus simplifying the experimental process.

According to an embodiment of the invention, the ratio of DNA of the chimeric marker to the transposase is 10 ng: 50-100 nM. Thus, the DNA of the chimeric marker is advantageously subjected to transposition repeatedly. The inventors have found that when the transposase input is too high, such as 200nM, the library fragments are too small and the main peak is located at about 290 bp. Because the Hi-C library is a chimeric of two DNA fragments, and the genome alignment of the sequencing data is carried out by respectively cutting one fragment from each end of the library, if the library is small, the alignment rate of the unique genome position of the effective part of the sequencing data is too low, and the alignment rate of the multiple genome positions of the ineffective part of the sequencing data is too high. Therefore, the inventors found through tests that when the ratio of DNA to transposase is 10 ng: the length of the library fragment is more suitable at 50-100nM (main peak 300-.

According to an embodiment of the present invention, the transposition-treated reaction system includes, based on 10ng of the DNA of the chimeric marker: 8-12. mu.l of transposition buffer; 0.2-1 μ L10% tween 20; 7-10 μ L of water; 0.5-3. mu.l of the transposase, wherein the transposition buffer comprises 10mM Tris-HCl pH 7.6 and 5mM MgCl₂. Thus, in this reaction system, the DNA fragment to be subjected to transposition treatment is appropriate in size.

According to the embodiment of the present invention, the transposition treatment is performed at a temperature of 50 to 60 ℃ for 5 to 15 minutes. Thus, under this temperature regulation, DNA fragmentation to an appropriate length interval is facilitated.

S300: capture processing

According to the embodiment of the invention, the transposition product is captured to obtain the captured DNA. Thus, the adaptor-labeled DNA labeled with the labeling substance is captured from the reaction system after transposition treatment for subsequent amplification, and the interference of foreign DNA with amplification is reduced.

According to an embodiment of the invention, the capturing process is a fishing process. According to a preferred embodiment of the invention, the fishing process is performed using streptavidin magnetic beads. Specifically, streptavidin magnetic beads are combined with biotin labeled on DNA, and chimeric DNA fragments with biotin labels and linkers at two ends are fished from a transposition product.

According to the embodiment of the present invention, the streptavidin magnetic beads are added in an amount of 5 to 10. mu.L, based on 1ng of the extracted DNA. Therefore, the method is beneficial to fully capturing the DNA with the biotin labels and the joints at two ends from the product, and avoids waste caused by excessive reagents.

S400: amplification treatment

According to the embodiment of the invention, the extracted DNA is subjected to amplification treatment to obtain the DNA library. Specifically, the extracted DNA may be amplified by PCR to obtain sufficient material. According to embodiments of the invention, the PCR amplified library may be further purified.

Application of library building method

Further, based on the above-described method for constructing a DNA library, according to a second aspect of the present invention, there is provided a method for obtaining chromatin interaction information in an individual cell. According to an embodiment of the invention, the method comprises: using the method described previously, so as to obtain a DNA library of said individual; sequencing and analyzing the DNA library so as to obtain biological information such as chromatin interaction information in individual cells. Therefore, the method for obtaining the biological information such as chromatin interaction information in the individual cell has simplified steps and shortened operation time, is particularly suitable for library construction of trace DNA samples, has high effective data proportion of sequencing and low noise single-terminal hanging value, and is favorable for pathological research of clinical diseases and scientific research of three-dimensional genomes. It should be noted that the method for constructing a DNA library has all the technical features and effects of the method for constructing a DNA library, and are not described in detail herein.

According to embodiments of the invention, sequencing may be accomplished by: classical Sanger sequencing, massively parallel sequencing, next generation sequencing, polony sequencing, 454 pyrosequencing, Illumina sequencing, SOLEXA sequencing, SOLiD sequencing, ion semiconductor sequencing, DNA nanosphere sequencing, Heliscope single molecule sequencing, single molecule real-time sequencing, nanopore DNA sequencing, tunneling current DNA sequencing, hybridization sequencing, mass spectrometry sequencing, microfluidic Sanger sequencing, microscope-based sequencing, RNA polymerase sequencing, in vitro virus high-throughput sequencing, Maxam-Gibler sequencing, single-ended sequencing, paired-end sequencing, deep sequencing, ultra-deep sequencing, and is particularly suitable for Illumina sequencing.

Then, according to embodiments of the invention, reads of sequencing may be processed using bioinformatics conduits to map long-range and/or genome-wide chromatin interactions to obtain biological information such as chromatin interaction information within individual cells.

Further, based on the above-described method for constructing a DNA library, according to a third aspect of the present invention, there is provided a method for obtaining biological information of an individual. According to an embodiment of the invention, the method comprises: using the method described previously, so as to obtain a DNA library of said individual; sequencing and analyzing the DNA library to obtain the individual biological information. Therefore, the method for obtaining the individual biological information has simplified steps and shortened operation time, is particularly suitable for constructing the Hi-C library of a trace DNA sample, has high sequencing effective data proportion and low noise single-end hanging value, and is favorable for research and clinical diagnosis in the field of three-dimensional genomes. It should be noted that the method for constructing a DNA library has all the technical features and effects of the method for constructing a DNA library, and are not described in detail herein.

Further, according to a fourth aspect of the present invention, there is provided a method of prenatal diagnosis or cancer screening. According to the rating of the present invention, the method is performed by the aforementioned method of constructing a DNA library or the aforementioned method of obtaining biological information of an individual or the aforementioned three-dimensional genome research method. Therefore, the steps of the method for constructing the DNA library and the method for obtaining the individual biological information are simplified, the operation time is shortened, the method is particularly suitable for constructing the library of the trace DNA sample, the effective data ratio of sequencing is high, the noise daggling value is low, and the obtained biological information is favorable for clinical diagnosis, particularly prenatal diagnosis and cancer screening. It should be noted that the method for constructing a DNA library has all the technical features and effects of the method for constructing a DNA library, and are not described in detail herein.

Further, according to a fourth aspect of the present invention, there is provided a kit comprising, according to an embodiment of the present invention: reagents, primers, mediation fragments, or a combination of at least one of them used in the aforementioned method for constructing a DNA library. Therefore, the method for constructing the DNA library by using the kit and the method for obtaining the chromatin interaction information and the biological information in the individual cell have the advantages of simplified steps, shortened operation time, high sequencing effective data proportion and low noise dangling value, are particularly suitable for constructing the library of trace DNA samples, and the obtained biological information is favorable for clinical diagnosis, particularly prenatal diagnosis and cancer screening. It should be noted that the kit has all the technical features and effects of the method for constructing a DNA library, and is not described herein again.

Further, according to a fifth aspect of the present invention, the present invention provides the use of the aforementioned kit in three-dimensional genomic banks or prenatal diagnosis or cancer screening. Therefore, the method for constructing the DNA library by using the kit and the method for obtaining the chromatin interaction information and the biological information in the individual cell have the advantages of simplified steps, shortened operation time, high sequencing effective data ratio, low noise dangling value, suitability for three-dimensional gene bank construction, and the obtained biological information which is favorable for clinical diagnosis, especially prenatal diagnosis and cancer screening.

It is to be noted here that the kit may be used for any application that is obvious to a person skilled in the art. The kit can comprise, for example, a plurality of association molecules, affinity tags, fixatives, restriction endonucleases, ligases, and/or combinations thereof. In some cases, the association molecule can be a protein, including, for example, a DNA binding protein (e.g., a histone or transcription factor). In some cases, the fixative may be formaldehyde or any other DNA cross-linking agent. In some cases, the kit may further comprise a plurality of beads. The beads may be paramagnetic and/or may be coated with a capture agent. For example, the beads may be streptavidin and/or antibody coated. In some cases, the kit may comprise an adaptor oligonucleotide and/or a sequencing primer. In addition, the kit may comprise a device capable of amplifying the read pairs using adaptor oligonucleotides and/or sequencing primers. In some cases, the kit can also include other reagents, including but not limited to lysis buffers, ligation reagents (e.g., dntps, polymerases, polynucleotide kinases, and/or ligase buffers, etc.), and PCR reagents (e.g., dntps, polymerases, and/or PCR buffers, etc.). The kit may also include instructions for using the kit components and/or generating read pairs.

The present invention is described below with reference to specific examples, which are intended to be illustrative only and are not to be construed as limiting the invention.

The scheme of the invention will be explained with reference to the examples. It will be appreciated by those skilled in the art that the following examples are illustrative of the invention only and should not be taken as limiting the scope of the invention. The examples do not specify particular techniques or conditions, and are carried out according to techniques or conditions described in literature in the art (for example, refer to molecular cloning, a laboratory Manual, third edition, scientific Press, written by J. SammBruke et al, Huang Petang et al) or according to product instructions. The reagents or apparatus used are not indicated by the manufacturer, but are conventional products available commercially, for example from Illumina.