Sponge proteins are more similar to those of Homo sapiens than to Caenorhabditis elegans

• Published in: Biological journal of the Linnean Society Vol. 71; no. 4; pp. 821 - 828
• Main Authors: GAMULIN, VERA, MÜLLER, ISABEL M, MÜLLER, WERNER E.G
• Format: Journal Article
• Language: English
• Published: Elsevier Science Ltd 01.12.2000
• Subjects: Caenorhabditis elegans; Porifera
• ISSN: 0024-4066; 1095-8312
• DOI: 10.1006/bijl.2000.0476

We compared 42 phylogenetically conserved proteins from four marine sponges [Porifera] with almost the complete set of Caenorhabditis elegans proteins and all known proteins from humans. The majority of the sponge proteins are significantly more similar to human than to C. elegans orthologues/homologues. This finding reflects the accelerated evolutionary rate in the C. elegans lineage, since sponges split off first from the common ancestor of all multicellular animals. Furthermore, three sponge/human proteins were not found in C. elegans: (2–5)A synthetase, DNA repair helicase and lens βγ -crystallin. Sponges are the source of the most ancient proteins already present in the common ancestor of all multicellular organisms. Some of these proteins were lost later during the evolution of individual animal lineages. These «found/lost» proteins may serve as molecular markers for an improved systematics of Metazoa. In addition, phylogenetically conserved sponge proteins can be very helpful for the evaluation of differences in evolutionary rates in different animal lineages. We therefore propose sponges as the reference animals in molecular evolutionary studies of Metazoa.