ATP-dependent DNA helicase implicated in DNA repair and the maintenance of genomic stability. Acts as an anti-recombinase to counteract toxic recombination and limit crossover during meiosis. Regulates meiotic recombination and crossover homeostasis by physically dissociating strand invasion events and thereby promotes noncrossover repair by meiotic synthesis dependent strand annealing (SDSA) as well as disassembly of D loop recombination intermediates (By similarity). In male germline stem cells (GSCs), plays a role in GSCs maintenance during larval germline development by modulating the expression of genes such as Stat92E and preventing DNA damage-induced checkpoint activation (PubMed:34644293). May play a role in female germline stem cell maintenance (PubMed:34644293). ATP + H2O = ADP + H(+) + phosphate Expressed in both male germline and somatic cells (at protein level) (PubMed:34644293). Expressed in ovarian germline stem cells (at protein level) (PubMed:34644293). Expressed in adult testes (at protein level) (PubMed:34644293). Expressed in the germarium including germline stem cells (PubMed:34644293). In males, RNAi-mediated knockdown in germ cells results in loss of male germline stem cells (GSCs) at day 14, appearance of branched fusomes and down regulation of a number of genes including Stat92E expression in adult testes (PubMed:34644293). In females, RNAi-mediated knockdown in germ cells results in a decrease in germline stem cells in the germaria (PubMed:34644293). RNAi-mediated knockdown in somatic cells or in differentiating spermatogonia does not affect GSC number in larval and adult testes or female germaria (PubMed:34644293). In the germline, simultaneous RNAi-mediated knockdown of Rtel1 and grp results in partial rescue of loss of germline stem cell (PubMed:34644293). In the germline, RNAi-mediated knockdown of Rtel1 in a lok mutant background results in partial rescue of loss of germline stem cell, including restored levels of Stat92E expression (PubMed:34644293). Belongs to the helicase family. RAD3/XPD subfamily.