Clustal

Clustal is a computer program used for multiple sequence alignment in bioinformatics. It is one of the most widely cited bioinformatics software with two of its academic publications amongst the top 100 papers cited of all time, according to Nature in 2014.

Since its first publication in 1988, the software and its algorithms have gone through several iterations, with ClustalΩ (Omega) being the latest version as of 2011. It is available as standalone software, via a web interface, and through a server hosted by the European Bioinformatics Institute.