DNA of 'minimal' cells (mycoplasmas) in the metagenomes of Arctic permafrost

Abstract

During the long geological time enzymes, nucleic acids, viruses and viable microorganisms can be kept in permafrost. It is difficult to get a holistic view of the microbial community of permafrost using only classical microbiological methods. The analysis of metagenomes of permafrost allowed us to identify the genetic material of ancient mycoplasmas - pathogens of humans, animals and plants. Sampling, isolation of total DNA from soil, sequencing (Illumina), metagenomic data processing (MG-RAST, M5nr, UniProt, Krona). Mycoplasma species composition in permafrost soil samples of different origin, but of comparable age (31-32 thousand years), was predicted. A comparative analysis of short polypeptides encoded by fragments of ancient DNA with corresponding parts of proteins of modern mycoplasmas was done. We discuss the phylogenetic history of Mollicutes, the plasticity of mycoplasma genomes, and the pathogenic potential of the permafrost.