Similarity analysis of biological sequence by alignment

Bioinformatics is an interdisciplinary field, specifically defined as computational part of molecular biology. Before the computers were brought in practice, biological experiments were performed either in living organism or in artificial environment. The large volumes of genetic data generated through biological experiments are not useful until it is analyzed and classified properly. The similarity analysis of sequence data leads to the study of structural and functional conservation, searching of biological database, sequence classification, and phylogenetic tree reconstruction. The principal objective of evolutionary (phylogenetics) studies is to follow the state of the system through long periods of time. However, it is impractical to repeat these evolutionary events in the laboratory. Therefore, the approaches for comparing biological sequences are mainly based on computational and statistical methods majorly called as alignment-free methods.