Evolutionary pathways of the calcitonin genes.

Since the development of molecular biology, knowledge about polypeptide hormones has increased rapidly. Recombinant DNA techniques have made it possible to establish the structure of genes encoding polypeptide hormones. The results have provided insight into the mechanisms underlying the increasing diversity of polypeptide hormones. Comparison of nucleotide sequences of various genes has revealed surprising similarities and variations. The calcitonin (CT) genes offered an opportunity for speculation about the evolutionary origin on one hand and relationships between these genes on the other.