Abstract: Provided is a linker element and a method of using the linker element to construct a sequencing library, wherein the linker element consists of a linker A and a linker B, the linker A is obtained through the complementary pairing of a long nucleic acid strand and a short nucleic acid strand, the 5? end of the long strand has a phosphoric acid modification, and the 3? end of the short strand has an enclosed modification, with enzyme sites in the short strand; and the linker B is a nucleic acid single strand, and the 3? end thereof can be in a complementary pairing with the 5? end of the long strand of the linker A. Using the linker element of the present invention for constructing a sequencing library ensures the linking directionality of the linkers while solving the problems of fragment interlinking, linker self-linking and low linking efficiency, and reducing the purification reaction between steps, shortening the linking time and reducing costs.

Abstract: A method and reagent for constructing a nucleic acid double-linker single-strand cyclic library.

Abstract: Provided are a target region enrichment method based on multiplex PCR, and a reagent, the method comprising: connecting a first linker and a second linker respectively at two ends of a nucleic acid segment containing target regions to be enriched so as to obtain a linker-connected product; performing a PCR amplification on the linker-connected product using a first primer specifically bound to the first linker and a second primer specifically bound to the second linker to obtain an amplified product, the first primer or the second primer having a first affinity label; capturing a single strand having the first affinity label in the amplified product using a solid phase carrier; performing single primer linear amplification using a third primer with the captured single strand as a template; performing exponential amplification using the third primer and the first primer, with the linearly amplified product as the template, to obtain a product containing the target regions.

Abstract: Provided are a method for constructing a nucleic acid single-stranded cyclic library and the reagents used therein. By the combination of interruption via a transposase with a restricted nick translation reaction, the method realizes a simple and rapid nucleic acid single-stranded cyclic library construction.

Abstract: Disclosed are a nucleic acid fragmentation method and a sequence combination. The method comprises the following steps: subjecting a denatured nucleic acid to annealing and an extension reaction by using a single-stranded 5?-end extension primer, wherein the single-stranded 5?-end extension primer comprises a sequencing platform adaptor sequence of a 5? end and a connected random sequence, and the random sequence is subjected to annealing on a random site of the denatured nucleic acid; and directionally connecting a double-stranded 3?-end adaptor sequence to the 3? end of the nucleic acid generated in the extension reaction, and carrying out denaturalization and purification to obtain a fragmented single-stranded nucleic acid with adaptor sequences on two ends.

Abstract: Provided is a method of constructing a sequencing library using an adaptor element in a bubble shape. The bubble-shaped adaptor is ligated to a DNA fragment respectively at the 3?-terminal and the 5?-terminal i.e., two bubble-shaped adaptors with same sequences are ligated in one step. The bubble-shaped adaptor-ligated product is then amplified with a primer complementary to the 3?-terminal of the long-chain nucleic acid of the bubble-shaped adaptor, so as to replace the non-paired sequence in the short-chain nucleic acid.

Abstract: Provided in the present invention are a method for constructing a nucleic acid single-stranded cyclic library and reagent kit thereof. The method comprises the steps of using a transposase embedding complex to randomly break nucleic acids and connect a first linker; connecting a second linker at a gap; performing a first PCR reaction, wherein the 5? end of one of the primers has a first affinity tag, resulting in a product with two ends connected to different linker sequences; binding the product to a solid vector having a second affinity tag; degenerating and separating single strands having no affinity tag; and cyclizing the single strands.