Participates in meiotic recombination, specifically in homologous strand assimilation, which is required for the resolution of meiotic double-strand breaks. Double stacked ring-shaped homooctamer (By similarity). Interacts with BRCA2 (By similarity). Interacts with the MND1-PSMC3IP heterodimer (PubMed:15834424). Interacts with RAD51AP1; the interaction is direct and stimulates DMC1-mediated homologous recombination (By similarity). Testis. In spermatocytes, shows punctate localization along chromosome axes specifically in early meiotic prophase I cells. Foci start to appear from the leptotene stage, reach their greatest number in the zygotene stage, in the early pachytene stage, the DMC1 foci mostly disappeared from autosomes and became restricted to the sex chromosomes. Belongs to the RecA family. DMC1 subfamily.