E value 


E value search for term

Expectation value. The number of different alignents with scores equivalent to or better than S that are expected to occur in a database search by chance. The lower the E value, the more significant the score. (NCBI).This represents the number of sequences with a score greater-than, or equal to, X, expected absolutely by chance. The E-value connects the score ("X") of an alignment between a user-supplied sequence and a database sequence, generated by any algorithm, with how many alignments with similar or greater scores that would be expected from a search of a random sequence database of equivalent size. Since version 2.0 E-values are calculated using Hidden Markov Models, leading to more accurate estimates than before. (SMART) (http://www.ornl.gov/sci/techresources/Human_Genome/posters/chromosome/ge...)