A group led by Dr. Mizue Anita of the Graduate School of Life Sciences, Tohoku University discovered that the bacterium Auraymonas has a genome with a very unique composition.
Ribosomal RNA is a fundamental component of life that is responsible for protein synthesis in all living organisms.It has been believed that the RNA gene should be on the chromosome in order to stably convey such important components to the offspring.In fact, in all previously known bacteria, the ribosomal RNA gene was on the chromosome.
In this study, the genome of the bacterial Auraymonas AU20 isolated from soybean is composed of one chromosome and eight small plasmids (DNA separate from the chromosome), and the ribosomal RNA gene is present in the plasmid rather than the chromosome. I confirmed that.It was also found that the plasmid in which the RNA gene was present is composed almost exclusively of ribosomal RNA genes, and there is no mechanism for accurate distribution to cells generated during cell division.
This study revealed that the genome of bacteria is dynamically changing in the process of adaptation and evolution of plants and the like to their habitat.This achievement overturns the conventional wisdom about the genome and gives a new perspective to future research on the regulation of gene function and gene exchange between organisms in nature.
Source: [Tohoku University] Discovery of a bacterium in which the ribosomal RNA gene has disappeared from the chromosome-Overturning the common wisdom of the genome-