BLAST searches and related applications are essential for analyzing gene and protein sequences. Define BLAST, describe basic features of this bioinformatics tool, and give an example of information provided by a BLAST search.

Verified step by step guidance

1. Step 1: Define BLAST by explaining that it stands for Basic Local Alignment Search Tool, which is a bioinformatics algorithm used to compare an input nucleotide or protein sequence against a database of sequences to find regions of similarity.
2. Step 2: Describe the basic features of BLAST, including its ability to quickly identify local alignments rather than global alignments, its use of scoring matrices to evaluate sequence similarity, and its statistical framework to assess the significance of matches.
3. Step 3: Explain that BLAST can be used for different types of searches such as nucleotide-to-nucleotide (blastn), protein-to-protein (blastp), and translated searches (blastx), depending on the input and database sequences.
4. Step 4: Discuss how BLAST outputs include important information such as the alignment score, E-value (expectation value) which indicates the likelihood of the match occurring by chance, and the identity percentage showing how similar the sequences are.
5. Step 5: Provide an example of information from a BLAST search, such as identifying a gene in an unknown DNA sequence by finding a highly similar known gene in the database, or predicting the function of a protein by comparing it to proteins with known functions.

Key Concepts

BLAST (Basic Local Alignment Search Tool)

BLAST is a bioinformatics algorithm used to compare an input nucleotide or protein sequence against a database to find regions of local similarity. It helps identify homologous sequences, infer functional and evolutionary relationships, and locate conserved domains.

Features of BLAST

BLAST performs rapid sequence alignments by breaking sequences into smaller words and extending matches to find high-scoring segment pairs. It provides statistical significance scores (E-values), alignment scores, and identifies similar sequences with varying degrees of identity and coverage.

Information Provided by a BLAST Search

A BLAST search outputs aligned sequences with similarity scores, E-values indicating match significance, and annotations such as gene or protein names. For example, it can reveal potential functions of an unknown gene by matching it to known genes in the database.