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Evolution is often called “blind” because it is not known. objective external forces governing natural selection. Recent studies indicate that mutations occurring in genetic material during evolution not random. These changes are caused on the one hand – physical properties of the genetic code, on the other – the need to preserve the critical properties of the protein. DNA structure is a sequence of pairs nucleotides. A certain combination of amino acids encodes proteins, involved in the construction of cellular structures or performing certain functions in the cell. It is logical to assume that random mutations contribute to better the survival of each organism in accordance with the natural selection. A previous study by Michael Garwin and his colleagues from The University of Alaska was dedicated to studying sections of DNA, responsible for the synthesis of ATP. ATP molecules provide the cell energy. Changes in DNA allow the species adapt to environmental changes, so such mutations referred to as “positive selection”. Garwin once contributed Salmon DNA sequence into your computer. Because of the big the number of repetitions of the same letters he made a mistake, but, not Noticing her, he continued to enter the code. Repeating sequence continued with the correct alternation of amino acids. After analyzing the discovered features, Garwin suggested that in a cell may have a similar error when copying a repeating plot of DNA. “The process is like buttoning a shirt. In the morning, more waking up badly, you can fasten one button incorrectly. When you get to the last button, you have to correct the mistake made at first, “says Garvin. In the cell,” fixing buttons “is manifested by a mutation in DNA in the form of a slip of threads, leading to incorrect pairing of amino acids. The presence of groups of repeats is a physical feature of DNA that allows effect on mutations, researchers say. The presence of a mutated DNA even if the sequence remains unchanged before and after it, leads to production not correctly functioning protein. Plot of DNA between stable Harwin called the mutation hotspot sequences. IN As part of the study, all DNA sites available for “positive selection” (contributing to the adaptation of the body to environment), their proximity to repetitive sequences. Pattern was confirmed in 97% cases. When studying other mutations DNA sequences were found to be combined in 60% of cases with repeating sequences. So most mutations do not happen by chance, at least analyzed in the study of DNA sequences. Most likely, a mutation is it is a combination of opposing forces: mating abnormally amino acids in the process of DNA replication and the desire to preserve protein function.
DNA Evolution
