Ancient expansion of the ribonuclease A superfamily revealed by genomic analysis of placental and marsupial mammals

Soochin Cho, Jianzhi Zhang

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25 Scopus citations


Members of the ribonuclease (RNase) A superfamily participate in a diverse array of biological processes, including digestion, angiogenesis, innate immunity, and possibly male reproduction. The superfamily is vertebrate-specific, with 13-20 highly divergent members in primates and rodents, but only a few members in chicken and fish. This has led to the proposal that the superfamily started off from a progenitor with structural similarities to angiogenin and that the suerfamily underwent a dramatic expansion during mammalian evolution. To date this evolutionary expansion and understand the functional diversification of the superfamily, we here determine its entire repertoire in the sequenced genomes of dog, cow, and opossum. We identified 7, 20, and 21 putatively functional RNase genes from these three species, respectively. Many of the identified genes are highly divergent from all previously known RNase genes, thus representing new lineages within the superfamily. Phylogenetic analysis indicates that the superfamily expansion predated the separation of placental and marsupial mammals and that differential gene loss and duplication occurred in different species, generating a great variation in gene number and content among extant mammals.

Original languageEnglish
Pages (from-to)116-125
Number of pages10
Issue number1-2
Publication statusPublished - May 24 2006
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Genetics

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