Involved in the homologous recombination repair (HRR) pathway of double-stranded DNA breaks arising during DNA replication or induced by DNA-damaging agents. Homodimer. Interacts with XRCC3. Detected in various tissues. More expressed in reproductive tissues than in vegetative tissues, with the highest level in young flower buds. By genotoxic stress and by DNA damage. May be due to a competing donor splice site. Belongs to the RecA family. RAD51 subfamily.