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Báo cáo y học: "New evolutionary frontiers from unusual virus genomes"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: New evolutionary frontiers from unusual virus genomes. | Minireview New evolutionary frontiers from unusual virus genomes Christopher Desjardins Jonathan A Eisen and Vishvanath Nene Address The Institute for Genomic Research 9712 Medical Center Drive Rockville MD 20854 USA. Correspondence Vishvanath Nene. E-mail nene@tigr.org. Jonathan Eisen. E-mail jeisen@tigr.org Published 2 March 2005 Genome Biology 2005 6 212 The electronic version of this article is the complete one and can be found online at http genomebiology.com 2005 6 3 212 2005 BioMed Central Ltd Abstract The sequences of two giant viral genomes Mimivirus and a polydnavirus have recently been published. Mimivirus has the largest known viral genome and encodes an unprecedented number of proteins whereas the polydnavirus genome has an extremely low coding density and does not encode DNA-replication proteins. These and other unusual features challenge the way we view the evolution and definition of viruses. If an alien landed on Earth and studied the biology here it might justifiably conclude that viruses run the planet. They are numerically the most abundant biological entities 1 and they are profoundly important in shaping the ecology and evolution of just about every species on Earth 2 . Yet viruses are not considered to be alive by most biologists and they have arguably fallen by the wayside in the genomics revolution 3 . The recent publication of the genome sequences of two unusual viruses however highlights the wealth of information that remains to be discovered through viral genomics. Here we discuss Mimivirus 4 and Cotesia congregata Bracovirus 5 CcBV and the interesting questions they raise concerning the biology and evolution of viruses. Both Mimivirus and CcBV are classified as double-stranded DNA dsDNA viruses and some of their features are summarized in Table 1. Mimivirus was discovered in amoebae 6 and it has a cycle of viral transmission and replication that is typical of many dsDNA viruses Figure 1a . Its name is derived from mimicking microbe in .