motif similarity evidence position-specific scoring matrix motif search evidence PSSM motif search snadendla eco A type of motif similarity evidence where the motif is represented by a position-specific frequency matrix (PSFM) that specifies the frequency of each base at each position of the motif, from which a position-specific scoring matrix (PSSM) can be derived under the framework of a log-likelihood ratio providing a scoring system based on the likelihood of a sequence given the motif, versus a genomic-frequency based null hypothesis. ECO:0005536 PSSM 2015-10-09T15:04:35Z CollecTF This technique is used to predict transcription factor binding sites in gene promoter regions by using a position weight matrix approach. (PMID:15604457).