Sequence Alignment Tool

The Sequence Alignment Tool enables rigorous pairwise comparison of biological sequences. It supports both global alignments, which optimize full-length sequences, and local alignments, which identify the best matching subsequences. Users provide two sequences, select a scoring matrix (for example, BLOSUM62 for proteins or a DNA-specific matrix), and set gap penalties. The tool applies a dynamic programming algorithm to compute an optimal alignment and outputs a numeric score along with the aligned sequences. It also produces a percent identity measure to quantify similarity and the alignment length to indicate overlap.
Conceptually the tool assigns substitution scores via the chosen matrix and applies penalties for gaps; it builds a scoring matrix, traces back the optimal path, and returns an interpretable alignment. Advanced options allow affine gap penalties and custom matrices, enabling fine-tuned analyses for specific datasets or teaching scenarios. Typical use cases include identifying conserved regions, validating hypotheses about homology, and teaching alignment concepts with concrete examples. The output is suitable for incorporation into reports or downstream analyses, with clear, reproducible parameters that can be re-run on other datasets.
What distinguishes this tool is its balance of flexibility and accessibility: it handles both DNA and protein alphabets, validates inputs, supports global and local modes, and delivers transparent scoring and alignment details without requiring local software installation.