Required for maintenance of chromosomal stability (PubMed:11239453, PubMed:14517836). Promotes accurate and efficient pairing of homologs during meiosis (PubMed:14517836). Involved in the repair of DNA double-strand breaks, both by homologous recombination and single-strand annealing (PubMed:15671039, PubMed:15650050, PubMed:30335751, PubMed:36385258). The FANCI-FANCD2 complex binds and scans double-stranded DNA (dsDNA) for DNA damage; this complex stalls at DNA junctions between double-stranded DNA and single-stranded DNA (By similarity). May participate in S phase and G2 phase checkpoint activation upon DNA damage (PubMed:15377654). Plays a role in preventing breakage and loss of missegregating chromatin at the end of cell division, particularly after replication stress (PubMed:15454491, PubMed:15661754). Required for the targeting, or stabilization, of BLM to non-centromeric abnormal structures induced by replicative stress (PubMed:15661754, PubMed:19465921). Promotes BRCA2/FANCD1 loading onto damaged chromatin (PubMed:11239454, PubMed:12239151, PubMed:12086603, PubMed:15115758, PubMed:15199141, PubMed:15671039, PubMed:18212739). May also be involved in B-cell immunoglobulin isotype switching. {ECO:0000250|UniProtKB:Q68Y81, ECO:0000269|PubMed:11239453, ECO:0000269|PubMed:11239454, ECO:0000269|PubMed:12086603, ECO:0000269|PubMed:12239151, ECO:0000269|PubMed:14517836, ECO:0000269|PubMed:15115758, ECO:0000269|PubMed:15314022, ECO:0000269|PubMed:15377654, ECO:0000269|PubMed:15454491, ECO:0000269|PubMed:15650050, ECO:0000269|PubMed:15661754, ECO:0000269|PubMed:15671039, ECO:0000269|PubMed:19465921, ECO:0000269|PubMed:30335751, ECO:0000269|PubMed:36385258}. This is the function of FANCD2 (FA complementation group D2, ENSG00000144554).