Evolutionary diversification of cathepsin genes in vertebrates

Abstract

Paralogous genes are a clear example of duplications and source of diversification in the evolution of the genomes of living beings. Here we addressed CTS genes that give rise to the proteolytic enzymes called cathepsins. After a thorough search in bibliographic databases and molecular sequences we found information about these genes is confusing. In order to identify the processes involved in their evolutionary diversification since the origin of terrestrial vertebrates to the present we analysed the phylogenetic relationships between the amino acid sequences of cathepsins. The species included in this study belong mainly to some specific taxa such as Mammals (Primates, Rodents, Ungulates, Carnivora and Marsupials), Birds and Bony Fishes. In general terms, among the 32 genes found in vertebrates, at least 4 of them have arisen due to duplications subsequent to the colonization of the terrestrial environment and 2 of them seem  to have been  lost in  the lineage of the Birds. Other modifications observed are mainly due to mutations such as amino acid substitutions or insertions/deletions (indels).