ClustalW is a widely used bioinformatics tool for multiple sequence alignment. It helps researchers align DNA, RNA, or protein sequences to identify similarities and differences among them. This alignment is crucial for understanding evolutionary relationships and functional characteristics of the sequences. The software employs a progressive alignment algorithm, which builds the alignment step by step, starting with the most similar sequences. ClustalW is user-friendly and can handle large datasets, making it a popular choice in fields like genomics and molecular biology for analyzing sequence data efficiently.