In this article, we will discuss DNA sequencing in a simple and easy way and try to understand its various important aspects.

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डीएनए अनुक्रमण

DNA is the molecule inside cells that contains the genetic information responsible for the development and function of an organism. DNA molecules allow this information to be passed from one generation to the next.

यह भी पढ़ें – 15+ DNA Facts in Hindi that everybody should know

डीएनए अनुक्रमण क्या है?

What is DNA sequencing?

Sequencing DNA means determining the sequence of the four chemical building blocks – called “bases” – and which make up a DNA molecule. DNA sequencing tells scientists what type of genetic information a particular DNA segment contains. Scientists, for example, can use sequence information to determine which parts of DNA contain genes and which parts contain regulatory instructions.

Indeed, in the DNA double helix, four chemical bases always form a “base pair” with the same partner. Adenine (A) always pairs with thymine (T) and cytosine (C) always pairs with guanine (G). This pairing is the basis of the mechanism by which DNA molecules are copied when cells divide, and the pair also underlies the methods by which most DNA sequencing experiments are performed. The human genome consists of approximately 3 billion base pairs that carry the instructions for making and maintaining humans.

Base-pair structure enables the DNA sequence to store large amounts of genetic information. This complementary base-pairing is the basis of the mechanism by which DNA molecules are copied , transcribed and translated, and pairing underlies most DNA sequencing methods.

Overall DNA sequencing is a laboratory technique used to determine the exact sequence of bases (A, C, G, and T) in a DNA molecule. DNA base sequences contain the information a cell needs to assemble proteins and RNA molecules. DNA sequence information is important to scientists investigating the function of genes.

यह भी पढ़ें – कोशिका विभाजन [Cell Division] – क्या, कब व कैसे? [Facts]

डीएनए अनुक्रमण मेथड

dna sequencing

English biochemist Frederick Sanger discovered sequencing in the 1970s. The Sanger method is a classical DNA sequencing method. After that the Next Generation Sequencing (NSG) appears and then after that the third generation sequencing emerges. Let us understand all three;

What is Sanger sequencing?

The Sanger sequencing method , also known as the “chain termination method”, was developed in 1977 by English biochemist Frederick Sanger and his colleagues. This method is designed to determine the sequence of nucleotide bases in a piece of DNA (typically less than 1000 base pairs in length). Sanger sequencing with 99.99% base accuracy is considered the “gold standard” for validating DNA sequences.

Next Generation Sequencing (NGS)

Next generation sequencing (NGS) also known as massively parallel sequencing; Technology has largely replaced Sanger sequencing with advantages such as cost efficiency and rapidity . NGS can sequence millions of pieces at once.

The development of NGS technology has accelerated genomics research. NGS can simultaneously sequence whole genomes with more than 100 genes and less input DNA . Although Sanger sequencing is widely used in the sequencing field, it offers several major advantages such as: (i) it uses low cost for single gene sequencing, (ii) it exhibits 99.99% accuracy. and (iii) it is particularly suitable for the validation sequencing of site-directed mutagenesis.

What is site-directed mutagenesis?
Site-directed mutagenesis is a molecular biology method used to make specific and deliberate changes to the DNA sequence of genes and any gene products. Site-specific mutagenesis, also called oligonucleotide-directed mutagenesis, is used to investigate the structure and biological activity of DNA, RNA and protein molecules, and for protein engineering. Site-directed mutagenesis is one of the most important laboratory techniques for creating DNA libraries
by introducing mutations into DNA sequences .

Third generation sequencing

Emerging third-generation sequencing, also known as long-read sequencing. It can examine billions of templates of DNA and RNA as well as detect unstable or altered methylations without bias.

Also read – DNA Test [Genetic Testing]: What, How, Meaning and Benefits..!

Applications of DNA Sequencing Technologies

DNA sequencing reveals genetic information, which can be about a particular DNA segment, an entire genome, or a complex microbiome.

Scientists can use sequence information to determine which genes and regulatory instructions are contained in a DNA molecule. And the DNA sequence can also be checked for specific characteristics of the gene.

Homologous DNA sequences from different organisms can be compared for evolutionary analysis between species or populations. In particular, DNA sequencing can reveal changes in a gene that may cause a disease.

DNA sequencing is used in medicine, including the diagnosis and treatment of diseases, and in epidemiological studies. DNA sequencing has the power to revolutionize food security and sustainable agriculture, including animal, plant and public health. It aims to improve agriculture through effective plant and animal breeding and reduce the risk from disease outbreaks.

Additionally, DNA sequencing can be used to protect and improve the natural environment for both humans and wildlife.

This was a brief discussion on DNA Sequencing, hope you have understood. Must read our other articles for better understanding.

  1. What is a DNA library ?In molecular biology, a library is a collection of DNA fragments that are stored and propagated in a population of microbes through the process of molecular cloning .
  2. What is molecular cloning ?Molecular cloning is a set of experimental methods in molecular biology used to assemble recombinant DNA molecules and direct their replication within host organisms.
  3. What is recombinant DNA or rDNA?Recombinant DNA ( rDNA ) is a technique where enzymes are used to cut and paste together DNA sequences of your choice.
    In other words, DNA which is made artificially by combining components of different organisms is called recombinant DNA.
  4. What is DNA methylation?DNA methylation is a biological process by which methyl groups are added to a DNA molecule. The process of methylation can change the activity of a DNA segment without changing the sequence .
  5. What is DNA Sequencing?DNA consists of a linear string of nucleotides, or bases, referred to by the first letter of their chemical names – A, T, C and G. The process of reducing the sequence of nucleotides in DNA is called DNA sequencing. Since the DNA sequence provides the information that the cell uses to make RNA molecules and proteins, establishing the sequence of DNA is important for understanding how the genome works.

डीएनए [DNA] बेसिक्स – सरल एवं सटीक सचित्र विश्लेषण
डीएनए और आरएनए [DNA and RNA] : अंतर एवं समानताएं
प्रोकैरियोटिक और यूकेरियोटिक कोशिकाओं में अंतर [सचित्र]
कोशिका [Cell] : परिभाषा, संरचना व इसके भाग [सचित्र व्याख्या]

References,
https://www.genome.gov/genetics-glossary/DNA-Sequencing
https://www.genome.gov/about-genomics/fact-sheets/A-Brief-Guide-to-Genomics
DNA Sequencing: Definition, Methods, and Applications
https://www.nature.com/scitable/topicpage/dna-sequencing-technologies-690/