passages.id: split_4_test_831_passage
passages.type: progene_text
passages.text: TRD is mediated by the t complex responder locus ( Tcr ) , whose transmission is elevated above Mendelian levels by additive contribution of several t haplotype - encoded quantitative trait loci ( QTLs ) called t complex distorters ( Tcd1 - Tcd5 ) .