The function of RAD51 (RAD51 recombinase, ENSG00000051180) is as follows. Homologous DNA recombinase that catalyzes strand exchange, a key step in DNA repair through homologous recombination (HR) (PubMed:12205100, PubMed:12442171, PubMed:15937124, PubMed:17515904, PubMed:17515903, PubMed:18417535, PubMed:19303847, PubMed:20231364, PubMed:20348101, PubMed:22325354, PubMed:23509288, PubMed:23754376, PubMed:24141787, PubMed:26681308, PubMed:27941124, PubMed:28575658, PubMed:32640219, PubMed:37499663, PubMed:38509361, PubMed:7988572). Binds to single-stranded DNA (ssDNA) in an ATP-dependent manner to form nucleoprotein filaments which are essential for the homology search and strand exchange (PubMed:12205100, PubMed:15937124, PubMed:17515904, PubMed:17515903, PubMed:18417535, PubMed:19303847, PubMed:15226506, PubMed:20231364, PubMed:20348101, PubMed:23509288, PubMed:23754376, PubMed:26681308, PubMed:28575658, PubMed:37499663, PubMed:39636933, PubMed:41166468, PubMed:38509361, PubMed:7988572). Catalyzes the recognition of homology and strand exchange between homologous DNA partners to form a joint molecule between a processed DNA break and the repair template (PubMed:12205100, PubMed:18417535, PubMed:19303847, PubMed:20231364, PubMed:20348101, PubMed:23509288, PubMed:23754376, PubMed:26681308, PubMed:28575658, PubMed:38459011). RAD51 targeting to ssDNA promotes removal of replication protein-A (RPA) from ssDNA and stabilization of RAD51-ssDNA filaments by blocking ATP hydrolysis (PubMed:20729859). Nucleosomal DNA is peeled from the histone surface by the RAD51 filament (PubMed:38509361). Recruited to resolve stalled replication forks during replication stress (PubMed:27797818, PubMed:31844045). Also required for homologous recombination during meiosis by acting as an non-catalytic accessory factor for DMC1 recombinase, enabling proper chromosome pairing and crossing over (By similarity). Plays a role in regulating mitochondrial DNA copy number under conditions of oxidative stress in the presence of RAD51C and XRCC3 (PubMed:20413593). Also involved in interstrand cross-link repair (PubMed:26253028). {ECO:0000250|UniProtKB:Q08297, ECO:0000269|PubMed:12205100, ECO:0000269|PubMed:12442171, ECO:0000269|PubMed:15226506, ECO:0000269|PubMed:15937124, ECO:0000269|PubMed:17515903, ECO:0000269|PubMed:17515904, ECO:0000269|PubMed:18417535, ECO:0000269|PubMed:19303847, ECO:0000269|PubMed:20231364, ECO:0000269|PubMed:20348101, ECO:0000269|PubMed:20413593, ECO:0000269|PubMed:20729859, ECO:0000269|PubMed:22325354, ECO:0000269|PubMed:23509288, ECO:0000269|PubMed:23754376, ECO:0000269|PubMed:24141787, ECO:0000269|PubMed:26253028, ECO:0000269|PubMed:26681308, ECO:0000269|PubMed:27797818, ECO:0000269|PubMed:27941124, ECO:0000269|PubMed:28575658, ECO:0000269|PubMed:31844045, ECO:0000269|PubMed:32640219, ECO:0000269|PubMed:37499663, ECO:0000269|PubMed:38459011, ECO:0000269|PubMed:38509361, ECO:0000269|PubMed:39636933, ECO:0000269|PubMed:41166468, ECO:0000269|PubMed:7988572}.