FlyBase curator comment: The P{5'} entry in FlyBase is used to denote the partial transposon present in an insertion when it is known that the inserted sequence is a deleted version of the P-element natural transposon (generated during transposition/excision), and where it is known that sequences have been deleted from the 3' end of the P-element. For details of what portion of the original P-element remains for an individual insertion of P{5'}, see the description in the insertion report and/or in any allele reports associated with that insertion.