Abstract: The present invention discloses a method for non-invasively detecting EGFR gene mutations in subjects, comprising the following steps: designing primers according to EGFR gene exons; extracting plasma DNAs in subjects; connecting the extracted plasma DNAs with tagging linkers; PCR pre-amplifying the tagging linkers connected plasma DNAs; cyclising the pre-amplified DNAs to obtain cyclised DNAs; PCR amplifying the cyclised DNAs using the designed primers; and high throughput sequencing the PCR amplified product and analyzing the EGFR gene mutations. The present invention also discloses a corresponding kit.

Abstract: Provided herein is a method of constructing a high throughput sequencing library for use in detecting chromosome copy number variation comprising mainly the following steps: (1) subjecting DNAs to be tested to random fragmentation by a double-strand DNA fragmentation enzyme; (2) end-filling and adding poly-adenine at the 3?end of the fragmented DNAs; (3) connecting the end-filled DNAs having a 3?end poly-adenine with sequencing linkers to obtain connected products; (4) purifying the connected products to obtain the sequencing library; wherein steps (1)-(3) are performed in a single reaction tube. Also provided is a kit for constructing a sequencing library for use in detecting chromosome copy number variation.

Abstract: The disclosure relates to a method for constructing a plasma Deoxyribonucleic acid (DNA) sequencing library. The method includes: extracting a plasma DNA; making the plasma DNA ligate to a sequencing linker, and purifying a ligation product; performing Polymerase Chain Reaction (PCR) amplification for the purified ligation product, purifying the PCR amplification product, and obtaining the plasma DNA sequencing library, wherein, the method does not include the step of performing 5?-terminus phosphorylation for the plasma DNA.

Abstract: The disclosure claims a cleaved Deoxyribonucleic acid (DNA) detection method, a DNA fragment detection kit and use thereof. Wherein, the method includes the steps of: designing primers according to a test site or a test region of the DNA fragment; cyclizing the DNA fragment to obtain acyclized DNA; implementing Polymerase Chain Reaction (PCR) amplification for the cyclized DNA by using the primers; and detecting the PCR amplification product. In the disclosure, by cyclizing the DNA fragment, the amplification can be implemented even if only one PCR primer can match with a template, thus, the adaption range and effective template amount of the primer amplification can be greatly increased, and the detection sensitivity of the DNA fragment can be greatly improved.

Abstract: The invention relates to a kit, a device and a method for detecting the copy number of fetal chromosomes and tumor cell chromosomes.