GEMC1 is a 334 amino acid nuclear protein that regulates DNA replication by promoting the recruitment of Cdc45 onto replication origins. A member of the GEMC1 family, GEMC1 is highly phosphorylated and interacts with chromatin during formation of the pre-replication complex. The gene encoding GEMC1 maps to human chromosome 3, which is made up of about 214 million bases encoding over 1,100 genes. Notably, there is a chemokine receptor gene cluster and a variety of human cancer related loci on chromosome 3. Particular regions of the chromosome 3 short arm are deleted in many types of cancer cells. Key tumor suppressing genes on chromosome 3 encode apoptosis mediator RASSF1, cell migration regulator HYAL1 and angiogenesis suppressor SEMA3B. Marfan Syndrome, porphyria, von Hippel-Lindau syndrome, osteogenesis imperfecta and Charcot-Marie-Tooth Disease are a few of the numerous genetic diseases associated with chromosome 3.