Good news! New tools for circular DNA sequencing

Jul 02, 2020

DNA, also known as deoxyribonucleic acid, we know that biological cells contain a large number of important biological macromolecules, basically one of them is a nucleic acid. DNA is a long polymer composed of repeating nucleotide units and is also a kind of nucleic acid. DNA carries the genetic information necessary for RNA and protein synthesis, and it is an indispensable macromolecule for biological development and normal operation. Before the cell divides, DNA replicates the genetic information of the organism during the replication process. Because it contains complete genetic information, people continue to study it.

At first, when people did not have the concept of DNA, the Swiss biochemist Friedrich Michelle had already separated this substance from the pus of the surgical bandage. But it was not called DNA at the time, but because this microscopic substance was located in the nucleus of the cell, it was called nuclear protein by everyone. It was more than 150 years ago. After this incident, people are just like opening the door to a new world, and a group of scientists is devoted to the study of genes.

After 90 years of exploration, Matthew Mercerson and Franklin Starr confirmed the replication mechanism possessed by DNA in the experiment and inspired the later Creek team to conclude that the genetic code is composed of three The bases are composed in a non-repetitive manner and are called codons. Later, some scientists solved the genetic code formed by these codons in 1961. Therefore, modern gene sequencing projects have also gradually begun.

Current research results divide DNA into three types: single-stranded DNA, closed-loop DNA, and junk DNA. Among them, single-stranded DNA has been studied more, and sequencing methods and technological methods are also more diversified. However, there has been little research on circular DNA, because the lack of effective methods for research and sequencing has hindered progress in this area.

It is understood that circular DNA is very common in the genomes of bacteria and viruses. Circular DNA refers to a closed circular DNA structure located outside the chromosome. Compared with free linear DNA, this circular DNA is not easily degraded by nucleases and is more structurally stable. Moreover, circular DNA is also widely present in various eukaryotes, including humans, with high tissue and disease specificity.

Recently, scientists have discovered a large amount of circular DNA in the nucleus of humans and plants, and also found this circular DNA in cancer cells that are not valued by people. After inferred by experts, it may even be able to reproduce rapidly with cancer cells. There is a certain correlation. Although the traditional view has always been that eukaryotic genomes usually form stable linear chromosomes, new research shows that whether in normal somatic cells or cancer cells, there is a large amount of extrachromosomal circular DNA, and even more, genetic information is stored.

Based on this, scientists have begun to investigate the role of circular DNA in cancer in recent years and overcome their sequencing technology difficulties. Kung Fu takes no pains. According to the physicist organization network, on May 14, a Canadian biologist invented a new tool called CIDER-Seq, which can sequence circular DNA. In fact, they designed a new algorithm based on the knowledge of molecular biology and bioinformatics and used this algorithm to obtain the complete sequence of circular DNA in the experiment. This technique has now been published by researchers on the Internet for other scientists to analyze circular DNA sequences.


This time, the new tool breaks through the original technical difficulties in circular DNA sequencing, or it will provide scientists with more abundant and accurate data for future research. Because the research also shows that many viruses infected with crops have circular DNA, this new technology can also bring benefits to agricultural development. Not only that, but the expanded field of circular DNA research is also expected to promote research on viruses, agriculture, and even cancer.

As we all know, now is the era of rapid development of biology. As a major hot spot in biology, DNA sequencing technology is still relentlessly updated to help scientists dig out more secrets from DNA sequences. As Craig Venter, a well-known expert in human genome research and the chief scientist of Celera Corporation of America said: The meaning of deciphering the genome code is just like in the era when electricity was just discovered, no one can imagine a personal computer, the Internet same. I believe that in the future, the development and progress of sequencing technology can improve people's quality of life to a higher level.