In 1977, the Maxam-Gilbert sequencing method was first developed based on the chemical modification of certain bases made by Allan Maxam and Walter Gilbert. The method used homopolymers and ribosome-bound tRNA ( Pierce, 2012). Initially, an indirect method of determining the nucleotide sequence of RNA was used as a method for determining the sequence of bases in DNA. All the early studies have somehow contributed to the current sequencing technologies by providing the basis of DNA molecules.ĭNA sequencing accurately indicates and determines the order of nucleotides in a DNA molecule. In 1953, Watson and Crick discovered DNA double-helix structures ( Watson and Crick, 1953). In 1952, Hershey and Chase revealed that genetic material in bacteriophages is DNA using 35S- and 32P-labeled protein and DNA, respectively ( Hershey and Chase, 1952). In 1948, Erwin Chargaff and colleagues found that the ratio of DNA bases is consistent the amount of adenine was the same as thymine, and the amount of guanine was always the same as cytosine ( Chargaff, 2012). In the late 1800s, Albrecht Kossel chemically analyzed nucleic acids and found four nitrogen bases: adenine, cytosine, guanine, and thymine ( Pierce, 2012). In 1868, Johann Friedrich Miescher found that there were a number of acidic phosphorus in the nucleus, and this nuclear material, which consists of protein and DNA, was called nuclein (currently, nucleic acid). Research on DNA structure has been performed for more than 100 years, but relatively recently, we have come to know how DNA encodes genetic information. In this article, we briefly review the principles and characteristics of each generation of sequencing technology as well as the latest trends. Consequently, third-generation sequencing that can produce much longer sequences and supplement the shortcomings of previous technologies has been developed. As a result, some researchers started seeking ways to generate longer reads. However, second-generation sequencing generates short reads, which are not desirable for full genome assembly. Due to in-depth sequencing, it can be used for a variety of genetics research applications, such as genotyping and gene expression studies. This is the reason why it is also called deep sequencing technology. Basically, the second-generation sequencing methods offer multiple depths of nucleotide sequences with short lengths. The second-generation technology initiated a new era of genomics research due to a large amount of data generated by innovative pyrosequencing technology. In the mid-2000s, sequencing technology evolved into second-generation sequencing methods that provided low-cost, high-efficiency, and high-throughput data, compared to the traditional first- generation sequencing methods such as Sanger and Maxam-Gilbert technologies.
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