National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
Biol Direct. 2013 Oct 23;8:25. doi: 10.1186/1745-6150-8-25.
The recently discovered Pandoraviruses are by far the largest viruses known, with their 2 megabase genomes exceeding in size the genomes of numerous bacteria and archaea. Pandoraviruses show a distant relationship with other nucleocytoplasmic large DNA viruses (NCLDV) of eukaryotes, lack some of the NCLDV core genes and in particular do not appear to be specifically related to the other, better characterized family of giant viruses, the Mimiviridae. Here we report phylogenetic analysis of 6 core NCLDV genes that confidently places Pandoraviruses within the family Phycodnaviridae, with an apparent specific affinity with Coccolithoviruses. We conclude that, despite their many unusual characteristics, Pandoraviruses are highly derived phycodnaviruses. These findings imply that giant viruses have independently evolved from smaller NCLDV on at least two occasions.
最近发现的潘多拉病毒是迄今为止已知的最大病毒，其 2 兆碱基对的基因组大小超过了许多细菌和古菌的基因组。潘多拉病毒与真核生物的其他核质大 DNA 病毒（NCLDV）关系较远，缺乏一些 NCLDV 的核心基因，特别是与其他特征更明显的巨型病毒家族——微病毒科没有明显的关系。在这里，我们报告了 6 个核心 NCLDV 基因的系统发育分析，这些分析明确将潘多拉病毒置于 Phycodnaviridae 科内，与 Coccolithoviruses 有明显的特定亲缘关系。我们的结论是，尽管它们有许多不寻常的特征，但潘多拉病毒是高度衍生的 Phycodnaviridae 病毒。这些发现意味着巨型病毒至少已经从较小的 NCLDV 独立进化了两次。
