 in 2003, the "DDB2" gene is located on human chromosome 11p11.2, spans a region of approximately 24 – 26 kb and includes 10 exons.The DDB2 protein contains five putative WD40 repeats (sequences of about 40 amino acids that can interact with each other) positioned downstream from the second exon.The WD40 motif identified in DDB2 is characteristic of proteins involved in the recognition of chromatin proteins.