Genome of the marsupial Monodelphis domestica reveals innovation in non-coding sequences

Nature. 2007 May 10;447(7141):167-77. doi: 10.1038/nature05805.


We report a high-quality draft of the genome sequence of the grey, short-tailed opossum (Monodelphis domestica). As the first metatherian ('marsupial') species to be sequenced, the opossum provides a unique perspective on the organization and evolution of mammalian genomes. Distinctive features of the opossum chromosomes provide support for recent theories about genome evolution and function, including a strong influence of biased gene conversion on nucleotide sequence composition, and a relationship between chromosomal characteristics and X chromosome inactivation. Comparison of opossum and eutherian genomes also reveals a sharp difference in evolutionary innovation between protein-coding and non-coding functional elements. True innovation in protein-coding genes seems to be relatively rare, with lineage-specific differences being largely due to diversification and rapid turnover in gene families involved in environmental interactions. In contrast, about 20% of eutherian conserved non-coding elements (CNEs) are recent inventions that postdate the divergence of Eutheria and Metatheria. A substantial proportion of these eutherian-specific CNEs arose from sequence inserted by transposable elements, pointing to transposons as a major creative force in the evolution of mammalian gene regulation.

MeSH terms

  • Animals
  • Base Composition
  • Conserved Sequence / genetics
  • DNA Transposable Elements / genetics
  • Evolution, Molecular*
  • Genome / genetics*
  • Genomics*
  • Humans
  • Opossums / genetics*
  • Polymorphism, Single Nucleotide / genetics
  • Protein Biosynthesis
  • Synteny / genetics
  • X Chromosome Inactivation / genetics


  • DNA Transposable Elements