Evolution of the Gonadotropin Hormone Beta (CGB) genes. Duplication of ancestral Luteinizing Hormone Beta (LHB) gene in primate lineage has given rise to a novel gene, CGB. (A) A simplified schematic presentation of the evolution of LHB/CGB genes in primates [15,16]. (B) Comparative structure of the human (GenBank reference: NG_000019) and the chimpanzee LHB/CGB cluster (this study, Genbank: accession number EU000308) drawn to an approximate scale. Coding genes are depicted as wide empty arrows in the direction of transcription on the sense strand. A – E indicate the intergenic regions. B' and C' denote putative duplications of the intergenic regions B and C. Identical color and pattern codes refer to the DNA segments within the cluster with highly similar sequences, the direction of the DNA sequence is indicated on the sense strand. Sequence identity within the cluster: between coding genes 85–99%; intergenic regions A and E 81%; C and C' 96%; B, B' and D ranging 81–98%.
Hallast et al. BMC Evolutionary Biology 2008 8:195 doi:10.1186/1471-2148-8-195