Characterization of the opossum immune genome provides insights into the evolution of the mammalian immune system
- Katherine Belov1,7,
- Claire E. Sanderson1,
- Janine E. Deakin2,
- Emily S.W. Wong1,
- Daniel Assange3,
- Kaighin A. McColl3,
- Alex Gout3,4,
- Bernard de Bono5,
- Alexander D. Barrow6,
- Terence P. Speed3,
- John Trowsdale6, and
- Anthony T. Papenfuss3
- 1 Faculty of Veterinary Science, University of Sydney, Sydney NSW 2006, Australia;
- 2 ARC Centre for Kangaroo Genomics, Research School of Biological Sciences, The Australian National University, Canberra ACT 0200, Australia;
- 3 Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, Parkville 3050, Australia;
- 4 Department of Medical Biology, The University of Melbourne, Victoria 3010, Australia;
- 5 European Bioinformatics Institute, Cambridge CB10 1SD, United Kingdom;
- 6 Immunology Division, University of Cambridge, Cambridge CB2 5DS, United Kingdom
Abstract
The availability of the first marsupial genome sequence has allowed us to characterize the immunome of the gray short-tailed opossum (Monodelphis domestica). Here we report the identification of key immune genes, including the highly divergent chemokines, defensins, cathelicidins, and Natural Killer cell receptors. It appears that the increase in complexity of the mammalian immune system occurred prior to the divergence of the marsupial and eutherian lineages ∼180 million years ago. Genomes of ancestral mammals most likely contained all of the key mammalian immune gene families, with evolution on different continents, in the presence of different pathogens leading to lineage specific expansions and contractions, resulting in some minor differences in gene number and composition between different mammalian lineages. Gene expansion and extensive heterogeneity in opossum antimicrobial peptide genes may have evolved as a consequence of the newborn young needing to survive without an adaptive immune system in a pathogen laden environment. Given the similarities in the genomic architecture of the marsupial and eutherian immune systems, we propose that marsupials are ideal model organisms for the study of developmental immunology.
Footnotes
-
↵7 Corresponding author.
↵7 E-mail kbelov{at}vetsci.usyd.edu.au; fax 61-2-9351-3957.
-
[Supplemental material is available online at www.genome.org.]
-
Article published online before print. Article and publication date are at http://www.genome.org/cgi/doi/10.1101/gr.6121807
-
- Received November 14, 2006.
- Accepted February 5, 2007.
-
Freely available online through the Genome Research Open Access option.
- Copyright © 2007, Cold Spring Harbor Laboratory Press
