Among bacteria can spread DNA, making them dangerous to human life.
Scientists from Canada and the USA have discovered why the harmless bacteria transformed into pathogenic microorganisms that can cause epidemics. It turned out that the reason is not only the transfer of genes from pathogenic microbes, but also in the adaptation of virulence polymorphism.
Adaptive polymorphism is a situation where in the population there are several varieties, the survival of each of which under certain conditions favored by natural selection. Famous example — butterfly birch moth (Biston betularia), which may have light or dark color. Morpha typica, whose wings have white-grayish color and dark spots, hiding from birds, camouflaged against the background of trunks birches. However, near cities and industrial areas the trees can be covered with soot, so have the advantage of butterfly morpha carbonaria with black wings.
Scientists have suggested that, by analogy with the B. betularia, part harmless bacteria have DNA that contribute to the emergence of infectious strains. To prove this, the researchers analyzed 43 of the genome sticks cholera (Vibrio cholerae). These bacteria, living in water, form many different groups. One of them includes microbes that have pathogenic DNA, which encodes the exotoxin is a protein, causing deadly diarrhea. However, genes of exotoxin and are nonpathogenic bacteria.
Researchers have decoded the DNA of microbes and compared their genomes. Was discovered gene variants (alleles) that enhance the ability of the bacteria to penetrate into the host organism, as well as those that weaken it. Scientists believe that the existence of adaptive polymorphism of virulence in the population is facilitated by certain environmental conditions. The alleles themselves are a breeding ground conducive to the consolidation of pathogenic genes that fall into V. cholerae by horizontal transfer.
Horizontal gene transfer — process in which an organism transfers genetic material to another organism other than its offspring. The result among bacteria can spread DNA, making them dangerous to human life. According to scientists, this phenomenon was also the reason for the appearance of multicellular life.
© 2016, z-news.link. All rights reserved.