Method and use for construction of sequencing library based on DNA samples

A method for determining a methylation state of a DNA sample, the method comprising:

• constructing a sequencing library based on the DNA sample;
• sequencing the sequencing library to obtain sequencing results of the DNA sample;
• aligning the sequencing results of a 5′-end and a 3′-end of the DNA sample respectively with a reference genome to determine position information of the 5′-end and the 3′-end;
• and
• analyzing a position of the DNA sample by comparison based on the position information of the 5′-end and the 3′-end to determine the methylation state of the DNA sample,
• wherein said constructing a sequencing library based on the DNA sample comprises:
• digesting the DNA sample with endonuclease to obtain a DNA sample with single-strand nicks;
• polymerizing the DNA sample with the single-strand nicks by using polymerase, dATP, dTTP, dGTP, and methylated dCTP to obtain a hybrid DNA, wherein the hybrid DNA comprises two strands that are reversely complementary to each other, a 5′-end sequence of each of the two strands is an original sequence of the DNA sample, a 3′-end sequence of each of the two strands is a synthetic sequence, and all bases C at the 3′-end sequence of each of the two strands are methylated;
• subjecting the hybrid DNA to a bisulfite treatment to obtain a converted hybrid DNA;
• and
• amplifying the converted hybrid DNA using specific primers to obtain a sequencing library based on a target region of the DNA sample, wherein the specific primers comprise first specific primers and second specific primers, the first specific primers are located at 5′-ends of the converted hybrid DNA, and the second specific primers are located at 3′-ends of the converted hybrid DNA.