The Limits of What Mutations Can Achieve

The Limits of What Mutations Can Achieve To try to answer the limits of mutation capacity, there is nothing better than an experiment by Richard Lenski, an evolutionary biologist at the University of Michigan. Lenski began this long experiment, which has been going on since 1988, to answer many questions about evolution, and to understand the nature of evolution and its mechanisms of action. The experiment began with twelve identical strains of Escherichia coli bacteria in about 20 years. An extraordinary experience, a huge number of generations and bacterial cells; it allowed us to closely observe the process of evolution. To realize the picture, you need to know that the number of these bacterial generations is approximately one million years in our lifetime. The results of this experiment were satisfactory to many evolutionists. Changes in modern generations made them more efficient and adapted to the environment in which they grew up in the laboratory. They increased in size and their growth rates over time through mutations and natural selection only. Thanks to the record created by Lenski and his assistants, it was possible to monitor this increase in adaptation in modern generations by putting modern generations and their ancestors in competition with the environment. Many changes have been observed in bacterial generations and a large number of scientific papers have been published, but perhaps those changes that have increased the fitness and adaptation of bacteria have not been as important as promoted by evolutionists, perhaps the event that caused the biggest fuss in that experiment is the development of the ability of bacteria to use citrate acid, which some considered the emergence of a new type of bacteria. One of the advantages of Escherichia bacteria is that they can neither use citric acid nor obtain it from the surrounding environment under aerobic conditions, but after 30,000 generations of Lensky's experiment, bacteria evolved and acquired a new function, i.e., new information; the ability to use citric acid, and rely on it as a carbon source under oxidative conditions. What has happened to the new generations and has increased their fitness and adaptation? What kind of information has the bacteria acquired? Was this remarkable development in the ability of bacteria to adapt as a result of the acquisition of new functions? The addition of new genetic information through mutations and natural selection? Lehigh University biochemist Michael Behe published a paper in the Quarterly Review of Biology detailing the results of the Lensky experiment and examining the molecular mechanisms behind apparent changes that increased the adaptation of new generations to the environment. After examining all the molecular details, Behe concluded that the adaptation and increase in fitness of the new generations of bacteria was not the result of adding new information or gaining new jobs, but on the contrary, this adaptation was the result of the destruction of some pre-existing functions and the loss of information, as a result of mutations that spoiled the work of mechanisms, and these modifications were useful evolutionary (the ability to reproduce quickly) and helped bacteria to develop, but in exchange for the loss of part of information. "By examining the sequences of Escherichia coli DNA around the suture sequences, the researchers found several genes responsible for the metabolism were excreted, as were some cell wall genes and others. In later work, Cooper discovered that all 12 strains were exposed to deletion mutations of the ribose operon actuator, which is responsible for manufacturing ribose sugar. When the number of generations exceeded 20,000, Lenski's team used sophisticated techniques to detect the molecular basis of adaptive changes. Using these techniques, they tracked and monitored the activity of 130 gene expression mutations, and found that 59 of them changed their activity from their ancestors, 47 of which had a lower level of activity or expression. of protein activity. The same genes have been exposed to different mutations but the result is the same; an increase in fitness and adaptability. This is strong evidence that these mutations have disrupted the functioning of the gene, so different mutations cannot have a single function. The mutations have caused a lack of information, not an increase. What does Lenski's experiment tell us? Isn't it a real-life practical example of evolution? Yes, it is an evolution, but an evolution in the wrong direction, not the kind of evolution required to transform the protocell (the common origin) into millions of species of organisms. The theory of evolution assumes that all species are created by regression from a common ancestor, a common ancestor that was very simple, but the species we see on Earth now appear to be highly complex. Evolution is supposed to be a long history of acquiring jobs and adding new information to new species, but Lenski’s experiment tells us nothing about where that information came from and how it was generated. Bacteria have evolved over time to become more viable than their predecessors, but until victory in that struggle for survival has paid a price by eliminating some of their functions, which seem to have served their ability to reproduce; the basic function that natural selection sees and works under, it is to reproduce faster than its predecessors and to achieve advantages that increase adaptation to the environment, sacrifice some other functions. The external appearance gives the impression that the new generations have acquired special features that have allowed them to be lost. All adaptive mutations may not be that bad. Some mutations can increase an individual's ability to adapt by giving them new functions such as the use of citric acid under oxidative conditions, but what is the rate of emergence of those mutations compared to those that tamper with the functions of the cell and spoil it? The ratio of beneficial to harmful adaptive mutations may not exceed one to one hundred as indicated by Behe in his paper, which means that the rate of bacterial function loss is much higher than the rate of new functions. It is not that the incidence of harmful mutations is higher than the incidence of beneficial mutations, but the incidence of mutations that increase the adaptation of bacteria to the surrounding environment by rooting out cell information is higher than the incidence of mutations that increase the adaptation of bacteria to the surrounding environment by adding new information and functions. If Behe is correct, molecular evolution faces many problems. Because the likelihood of loss (or decrease) of function logically requires that the molecular functions in the evolutionary population be depleted as a result of loss or decrease of functions. This experiment, the Lenski experiment, was the largest of its kind, and I couldn't find better ways to find the limits of mutations' ability to add new biological information to organisms, but it seems that we didn't find our prey here, all we found was a disruption of genes, a loss of function, and a reduction in some activities in the cell, those mechanisms can't explain the presence of antibiotic resistance mechanisms in bacteria that are so complex and specialized, but we may see that these mechanisms are some of acquired resistance. (1) Michael J. Behe, “Experimental Evolution, Loss-of-Function Mutations, and ‘The First Rule of Adaptive Evolution’”, The Quarterly Review of Biology, Vol. 85(4):1-27 (December 2010). — Source: Published on Facebook's "Braheen Center" page https://www.facebook.com/braheen.org/posts/pfbid061EQcsuMeMkJdx9ySPHNtaDEjnnQZSk8nPp1NjyVzNuuoMVATsua5ATc71FdGqvCl