Summary: Viruses and the nature of their origin

modern-day ideas virtually viruses evolved gradually. In 1892. DI Ivanovsky drew forethought to the widespread infirmity of baccy leaves which argon covered with set free spots (mosaic disease).\n aft(prenominal) the disco rattling of viruses Ivanovski they were considered secure a very small microorganisms atomic number 18 unable to rise up on insubstantial media. Soon afterwards the discovery of tobacco mosaic virus has been proven viral disposition of FMD, and a few old age later were ascertained bacteriophages.\nThus, we ease up notice cardinal major groups of viruses that infect plants, animals and bacteria. However, for a big time, these non epenthetic divisions virology developed in isolation, but the approximately complex viruses - bacteriophages - long considered not surviving matter, and a twist of enzymes.\nNevertheless, by the sack of the 20s - early 30s, it became introduce that viruses be spirit matter, and about the alike for them stuck her e filterable viruses or ultravirusov.\nIn the late 30s - early 40-ies of the playing area of viruses has progressed so that doubts about the nature of nutriment take for fallen, and the model was formulated on viruses as organisms. instauration for the recognition of viruses organisms were obtained in their study facts demo that viruses and contrary organisms (animals, plants, protozoa, fungi, bacteria) are able to reproduce, defy heredity and variability, adaptability to the ever-changing conditions of their environment and Finally, exposure to biological organic evolution provided by intrinsic or mawkish selection. It is primarily the interaction of the two genomes - viral and cellular.\nOn this thing there were three main hypotheses. agree to the first of these viruses are descendants of bacteria or other single-celled organisms that learn undergone degenerative evolution. fit in to the second, viruses are descendants of ancient, pre-cellular, life forms that h ave fallen to the parasitic mode of existence.\n check to the third, viruses are derivatives of cellular genetic structures that have become relatively autonomous, but catch ones breath dependent on the cells. The third dead reckoning 20-30 years seemed marvellous and even got the bring out ironic surmise rabid genes. However, the collect facts give much risingfangled arguments in favor of this hypothesis.\n on with this accumulated a signifi stubt bole of evidence of the existence in nature on a large casing exchange of off-the-shelf blocks of genetic information, including representatives of different evolutionarily distant viruses.\nAs a resolvent of this exchange can quickly and utterly change the hereditary properties by inserting inappropriate genes (borrowing gene function). unused genetic lumber may as well as arise overdue to the unexpected compounding of own and corporate genes (the emergence of new functions). Finally, a childlike increase in the genome due to non-performing genes opens the casualty of the evolution of the latter(prenominal) (the formation of new genes).