Camparition of Variants of Blast (Basic Local Alignment Search Tool)

Abstract

Now a days, large quantities of gene sequences of related species of plants, animals and microorganisms show complex patterns of similarity to one another and many molecular biologists are convinced that an understanding of sequence evolution is the first step towards understanding the evolution itself. In fact this is one of the most fascinating aspects of the study of evolution. Thus the comparison of gene sequences or biological sequence analysis is one of the processes used to understand sequence evolution. Just as the ancient Greeks used comparative anatomy to understand the human body and linguists used the Rosetta stone to decipher Egyptian hieroglyphs, today we can use comparative sequence analysis to understand genomes. There is variety of different tools available to perform sequence analysis. Various DNA sequences alignment tools have been developed. Various software packages of automated tools have been developed that had improved the efficiency of much biological research. Fast, economical, flexible, and extensible computing power is making it increasingly attractive to scientists in many areas of research, including biology. More generally, the open source movement has greatly benefited biological research. The combination of data availability and free software is revolutionizing this field. BLAST is the efficient tool used for biological searches. There exists variants of Blast which are developed to overcome the limitations of Main BLAST Tool. I studied variants of BLAST (BLASTN, BLASTP, BLASTX, TBLASTN, TBLASTX,PSIBLAST). Each variant has advantages and disadvantages over one another. Different tools work according to the different parameters. These parameters add to the performance of the algorithm. I did analysis of these variants and compared these tools on the basis of their algorithms, parameters, and performance. Situation is depicted that in which condition, which variant is more advantageous and under which circumstances different versions should use. How they can be improved by eliminating their deficiencies and by adding new features.