Provisional PDF – the final version will be printed in the BioScience Education e-
Generating truly random sequences by throwing dice can be used to illustrate how unrelated sequences may be found by BLAST, how to judge the statistical significance of the hits, and how the database size influences the statistics.
Abstract
An important part of teaching students how to use the BLAST tool for searching large sequence databases, is to train the students to think critically about the quality of the sequence hits found – both in terms of the statistical significance and how informative the individual hits are. This paper describes how generating truly random sequences by throwing dice can be used to illustrate how unrelated sequences may be found by BLAST, how to judge the statistical significance of the hits, and how the database size influences the statistics.