DNA Sequencing

Abstract

Methods to determine the sequence of DNA were developed in the late 1970s (1,2) and have revolutionized the science of molecular genetics. The DNA sequences of many different genes from diverse sources have been determined, and the information is stored in international databanks such as EMBL, GenBank, and DDBJ. Many scientists now accept that sequence analysis will provide an increasingly useful approach to the characterization of biological systems. Projects are already underway to map and sequence the entire genome of organisms such as Escherichia coli, Saccharomyces cerevisiae, Caenorhabditis elegans, and Homo sapiens. In the recent past, large-scale sequencing projects such as these were often dismissed as prohibitively expensive and of little short-term benefit, while DNA sequencing itself was seen as a repetitive and unintellectual pursuit. However, this view is now changing and most scientists recognize the importance of DNA sequence data and perceive DNA sequencing as a valuable and often indispensable aspect of their work. Recent technological advances, especially in the area of automated sequencing, have removed much of the drudgery that used to be associated with the technique, and modern innovative computer software has greatly simplified the analysis and manipulation of sequence data. Large-scale sequencing projects, such as the Human Genome Project, produce the DNA sequences of many unknown genes. Such data provide an impetus for molecular biologists to apply the techniques of reverse genetics to produce probes and antibodies that can be used to identify the gene product, its cellular location, and its time of appearance in the developing cell (3). A function can be assigned by mutant analysis or by comparison of the deduced amino acid sequence with proteins of known function. Therefore, DNA sequencing can act as a catalyst to stimulate future research into many diverse areas of science.