AP BIOLOGY

Detailed explanation-1: -The program compares nucleotide or protein sequences to sequence databases and calculates the statistical significance of matches. BLAST can be used to infer functional and evolutionary relationships between sequences as well as help identify members of gene families.

Detailed explanation-2: -BLAST is a heuristic that finds short matches between two sequences and attempts to start alignments from these ‘hot spots’. In addition to performing alignments, BLAST provides statistical information to help decipher the biological significance of the alignment; this is the ‘expect’ value, or false-positive rate.

Detailed explanation-3: -A BLAST search enables a researcher to compare a subject protein (called a query) with a database of sequences, and identify database sequences that resemble the query sequence above a certain threshold.

Detailed explanation-4: -Searching for similarities between biological sequences is the principal means by which bioinformatics contributes to our understanding of biology. Of the various informatics tools developed to accomplish this task, the most widely used is BLAST, the basic local alignment search tool.