In the July 19, 2013 issue of the journal Science, an interesting article describes the discovery and characterization of two “giant” viruses that are proposed to comprise the first members of the “Pandoravirus” genus.
Nadege Philippe and co-workers obtained the viruses from sediment samples in Chile and Australia and found that they have no morphological resemblance to any previously defined virus families. The investigators isolated the genomes of these viruses and sequenced them using a variety of NextGen methodologies. They then assembled the reads into contigs and characterized them using various sequence similarity algorithms (including NCBI’s BLAST and CD-Search). Interestingly, while related to each other, the genomes were not similar to those of any other organism or virus. Additionally, 93% of protein-coding sequences had no recognizable homologs.
The annotated sequences are now part of GenBank and are accessible by searching the Nucleotide database with the accessions KC977571 and KC977570. (Please note that the accessions originally reported in the Science article were incorrect.)
- Isolated from coastal sediments collected at the mouth of the Tunquen river on the coast of central Chile, the sequence in KC977571 consists of 2,473,870 base pair DNA sequence encoding 2,542 putative proteins.
- Isolated from the mud at the bottom of a freshwater pond near Melbourne, Australia, the sequence in KC977570 consists of 1,908,524 base pair DNA sequence encoding 1,487 putative proteins.
For more information:
- Philippe, et al. “Pandoraviruses: amoeba viruses with genomes up to 2.5 Mb reaching that of parasitic eukaryotes.” Science. 2013 Jul 19;341(6143):281-6. doi: 10.1126/science.1239181.