A virus found in the sea off Chile is the biggest in the world, harbouring more than 1000 genes, surprised scientists report. The genome of Megavirus chilensis is 6.5 per cent bigger than the DNA code of the previous virus record-holder, Mimivirus, isolated in 2003. Viruses differ from bacteria in that they are usually far smaller and cannot reproduce on their own, needing to penetrate a host cell in which to replicate. Advertisement: Story continues below But M. chilensis is such a giant that it surpasses many bacteria in size and is genetically the most complex DNA virus ever described. It was taken from seawater sample close to the shore of Las Cruces, Chile. Its host organism is unknown. Read more: www.brisbanetimes.com.au...
DNA viruses include pox viruses and herpes viruses, but M. chilensis "doesn't seem to be harmful for humans", said Jean-Michel Claverie, of France's National Centre for Scientific Research.
Originally posted by nineix
I'm always amused at the panicky old lady reaction from most people when anyone says words like 'virus', or 'radiation'.
Most viruses are completely harmless to humans.
Implications of discovery
Two Megavirus specific features are of fundamental importance. First, even if its new record-sized genome only represent a small 6% increment compared to the second largest Mamavirus genome, it indicates that we have not yet reached the limit of viral genome sizes, and that even more complex viruses may remain to be discovered, most likely in aquatic environment, the viral diversity of which has been barely scratched by recent metagenomic studies.
Second, the presence of three additional aminoacyltRNA synthetases in the Megavirus genome, with a total of seven, definitely rules out their independent acquisition by lateral transfer from a host. In addition, the phylogenic analysis of their amino acid sequences does not cluster them with any known protozoan clade, but rather connect them deeply to eukaryotic domain.
The conclusion then becomes inescapable that the genome of these giant viruses originated from an ancestral cellular genome (thus endowed of a translation apparatus, with all 20 aminoacyl tRNA synthetases) from which today’s Megaviridae derived by a number of lineage specific genome reduction events, a scenario akin to the one followed by all parasitic organisms. As indicated by the deep rooting of their phylogeny, the Megaviridae lineage might be very old, eventually predating the emergence of modern eukaryotes, or be contemporary and/or linked to the emergence of the nucleus. 5 Alternatively, it could be derived from an extinct cellular domain (the controversial 4th domain of the Tree of Life), many genes of which would have managed to persist in today’s giant viral genomes.
Originally posted by ExCommando
reply to post by nineix
I don't see your point. Virus' are potentially huge killers, and this is the "biggest virus on earth", surely there is some justification with ref: to concern of possible effects on humans?