May 10, 2007: Genome Sequence of Opossum Was Completed
Opossum, also known as Monodelphis domestica, is the first marsupial species to be sequenced. The genome sequence of possum provided a unique perspective on the organization and evolution of mammalian genomes, showing that evolutionary pressures lead the way in influencing gene regulatory mechanism followed by changing gene or protein sequence.
Reference
http://www.nature.com/nature/journal/v447/n7141/full/nature05805.html
Image Source
http://animaldiversity.org/collections/contributors/phil_myers/classic/monodelphis/