Localization of Blvr, biliverdin reductase, on mouse chromosome 2

Biliverdin reductase, Blvr, has been mapped on mouse chromosome 2, using an electrophoretic variant. The gene order obtained from a five-point cross and calculating genetic distance as percentage recombination +/- SE was Blvr-3.7 +/- 1.8-pa-0.9 +/- 0.9-we-5.6 +/- 2.2-un-2.8 +/- 1.6-a. Thus, Blvr must be closely linked to several genes, limb deformity (ld), Strong's luxoid, (1st), and small eye (Sey), involved in limb and/or craniofacial development. In man, GCPS, Greig cephalopolysyndactyly syndrome, associated with limb anomalies and craniofacial dysmorphism has been assigned to 7p13. Thus GCPS probably maps near to BLVR, the human homolog of Blvr, and also to TCRG, T-cell receptor gamma. However, in mouse, Blvr and Tcrg are asyntenic, and the proposed murine homolog of GCPS is extra toes (Xt), closely linked to Tcrg on chromosome 13. Possibly in the common ancestor of man and mouse there was a cluster of genes for craniofacial and limb development, which remains linked to BLVR and TCRG in man, but has become broken up in the mouse with the loss of synteny of Blvr and Tcrg, although linkage of some genes in the cluster to Blvr and Tcrg has been retained.