CSHL scientists are part of consortium that sequences platypus genome

In all, the team identified 180 novel miRNAs that appear to be unique in the platypus and monotremes, most notably a large cluster of miRNAs on platypus chromosome X1, expressed almost exclusively in the testis. The cluster appears to be evolving rapidly, which is characteristic of the mammalian trait of fast-evolving male reproductive machinery. Also of special interest was evidence that the platypus genome encodes three proteins of the so-called PIWI family, which is involved in the genesis of a newly discovered class of small RNAs called piwi-, or piRNAs. In platypus, in contrast to other mammals studied to date, the piRNA system appears to play an active role in germline defense, within the mature testis.

In sum, Dr. Hannon noted, “the small RNA complement of the platypus has highlighted both unique and conserved roles for miRNAs and piRNAs in monotremes; at the same time, it has given us fascinating insight into the evolution of small RNA pathways in mammals.”

“Conservation of small RNA pathways in platypus,” appears in Genome Research on May 9, 2008. The full citation is: Elizabeth P. Murchison, Pouya Kheradpour, Ravi Sachidanandam, Carly Smith, Emily Hodges, Zhenyu Xuan, Manolis Kellis, Frank Grutzner, Alexander Stark, and Gregory J. Hannon. The article appears online at: http://www.genome.org/cgi/doi/10.1101/gr.073056.107.

The consortium’s paper, “Genome analysis of the platypus reveals unique signatures of evolution,” appears in Nature on May 9, 2008. The lead author is Wesley C. Warren; CSHL authors include: Elizabeth P. Murchison, Ravi Sachidanandam, Carly Smith, and Gergory J. Hannon. The paper can be obtained online at: http://www.nature.com/nature/journal/v453/n7192/pdf/nature06936.pdf

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