miRNA seed types. Nine seed types are categorized in two groups; "Stringent" (8mer, 7mer-A1, and 7mer-m8) and "Non-stringent" (6mer, GUM, GUT, LP, BM and BT). GUM and GUT allow one GU wobble in the seed region. GUM has the U on miRNA whereas GUT has the U on the target. LP, BM and BT allow one mismatch. LP has one loop, BM has one bulge on miRNA, and BT has one bulge on the target.
Saito and Sætrom BMC Bioinformatics 2010 11:612 doi:10.1186/1471-2105-11-612