What is Basic Local Alignment Search Tool (BLAST)?

BLAST (Basic Local Alignment Search Tool) is a powerful algorithm and program used extensively in bioinformatics. It's a champion at finding regions of similarity within biological sequences, like DNA or protein sequences.

What are the main features of BLAST?

• Compares Sequences: BLAST takes a query sequence (e.g., a newly discovered DNA fragment) and compares it against a vast database of known sequences.
• Statistical Significance: It calculates the statistical significance of any matches found. This helps researchers distinguish between random similarities and those with potential biological meaning.
• Different Algorithms: BLAST offers various algorithms optimized for different types of comparisons (e.g., nucleotide-nucleotide, protein-protein, protein-nucleotide).

Why is BLAST important?

• BLAST is a fundamental tool for bioinformatics research.
• It allows researchers to:
  • Identify unknown sequences by comparing them to known ones, aiding in gene or protein function prediction.
  • Study evolutionary relationships between organisms by analyzing sequence similarities.
  • Design primers for further experiments based on identified regions of similarity.

What are applications of BLAST in practice?

• Gene Discovery: Researchers can use BLAST to compare newly sequenced DNA to known genes, potentially uncovering novel genes or mutations.
• Drug Discovery: By identifying proteins involved in diseases, BLAST helps researchers search for potential drug targets.
• Microbiome Analysis: BLAST is crucial for analyzing the vast amount of sequence data generated in microbiome studies to understand the composition and function of microbial communities.

Practical example

• Imagine a scientist discovers a mysterious virus. They can use BLAST to compare the viral genome sequence against known databases. If a match is found with a high statistical significance, it suggests the newly discovered virus might be related to a previously identified one, aiding in developing diagnostic tests or treatments.

Critical comments

• BLAST results require careful interpretation. Similar sequences don't necessarily guarantee identical functions.
• The choice of the appropriate BLAST algorithm and database is crucial for obtaining meaningful results.
• With ever-increasing sequence data, interpreting BLAST outputs can be computationally intensive and require expertise.