Image: Nature Communication
Biologists from the French National center for scientific research (Paris) found that giant viruses belonging to the genus of pandorabrowse (Pandoravirus) that can create new genes from scratch, which is considered rare and unlikely evolutionary phenomenon. Article scientists published in the journal Nature Communication.
Pandorabrowse infecting amoebae Acanthamoeba castellanii, was opened in 2013 and at that time were the giant viruses. By 2018, the genus includes only three species — Pandoravirus salinus, Pandoravirus dulcis and Pandoravirus inopinatum. The first type was isolated from shallow sediments in Chile, the second of the mud from the bottom of the pond in Australia and a third in a patient with amoebic keratitis in Germany. However, in the new work, the group of scientists has described three strains of pandorabrowse: Pandoravirus quercus, isolated from soil in France, Pandoravirus neocaledonia from a mangrove swamp in New Caledonia (Pacific ocean) and Pandoravirus macleodensis from a freshwater pond in Australia.
The researchers analyzed and compared the genome, the transcriptome (set of transcripts, DNA) and protein in all of six kinds of pandorabrowse. It turned out that 82-87% of the genome subjected to the process of transcription (synthesis of RNA on the matrix DNA), but only 62-68 per cent carrying information about the structure of the protein it was coding.
The analysis also showed that genes specific to clade (a group with common ancestry of the organisms) and strains having a similarity with non-coding intergenic intervals, and the universal genome, that is, the set of genes possessed by each strain.
This is due to the fact that these genes are randomly arose from non-coding regions, however, under the influence of natural selection, they became similar to the genes characteristic of the entire family of viruses. Such an evolutionary scenario in which a new coding genes can emerge from scratch, and not copied or transferred from other organisms, has long been considered statistically unlikely, however, recently it is confirmed by the results of studies of the genomes of yeast, fruit flies, rezhevichi tal, mammals, including primates.
Video, photo All from Russia.