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Beneficial Genetic Mutations Examples

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Last Updated: 02 July 2021

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No; only a small percentage of mutations cause genetic disordersamost have no impact on health or development. For example, some mutations alter a gene's DNA sequence but do not change the function of protein made by the gene. Often, gene mutations that could cause genetic disorder are repaired by certain enzymes before a gene is expressed and an altered protein is produce. Each cell has a number of pathways through which enzymes recognize and repair errors in DNA. Because DNA can be damaged or mutate in many ways, DNA repair is an important process by which the body protects itself from disease. A very small percentage of all mutations actually have a positive effect. These mutations lead to new versions of proteins that help an individual better adapt to changes in his or her environment. For example, beneficial mutation could result in protein that protects individuals and future generations from new strains of bacteria. Because a person's genetic code can have large number of mutations with no effect on health, diagnosing genetic conditions can be difficult. Sometimes, genes thought to be related to particular genetic condition have mutations, but whether these changes are involved in development of condition has not been determine; these genetic changes are known as variants of unknown significance or. Sometimes, no mutations are found in suspected disease - related genes, but mutations are found in other genes whose relationship to particular genetic condition is unknown. It is difficult to know whether these variants are involved in disease. The University of Utah Genetic Science Learning Center provides information about genetic disorders that explains why some mutations cause disorders but others do not. The National Human Genome Research Institute provides information about human genomic variation. Cold Spring Harbor National Laboratoryas DNA From Beginning explains the discovery of DNA repair mechanisms in cells and introduces researchers who work to understand these mechanisms. Force explains the significance of variants of unknown significance in cancer.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

The Unusually Well

Mutations are changes in genetic sequence, and they are the main cause of diversity among organisms. These changes occur at many different levels, and they can have widely differing consequences. In biological systems that are capable of reproduction, we must first focus on whether they are heritable; specifically, some mutations affect only individuals that carry them, while others affect all of the carrier organism's offspring, and further descendants. For mutations to affect organism's descendants, they must: 1 occur in cells that produce the next generation, and 2 affect hereditary material. Ultimately, interplay between inherit mutations and environmental pressures generates diversity among species. Although various types of molecular changes exist, word mutation typically refers to change that affect nucleic acids. In cellular organisms, these nucleic acids are building blocks of DNA, and in viruses they are building blocks of either DNA or RNA. One way to think of DNA and RNA is that they are substances that carry long - term memory of information required for organism's reproduction. This article focuses on mutations in DNA, although we should keep in mind that RNA is subject to essentially the same mutation forces. If mutations occur in non - germline cells, then these changes can be categorized as somatic mutations. The word somatic comes from the Greek word soma, which means body, and somatic mutations only affect the present organism's body. From an evolutionary perspective, somatic mutations are uninteresting, unless they occur systematically and change some fundamental property of an individual - such as capacity for survival. For example, cancer is a potent somatic mutation that will affect a single organism's survival. As different focus, evolutionary theory is mostly interested in DNA changes in cells that produce the next generation. The statement that mutations are random is both profoundly true and profoundly untrue at the same time. The true aspect of this statement stems from the fact that, to the best of our knowledge, consequences of mutation have no influence whatsoever on the probability that this mutation will or will not occur. In other words, mutations occur randomly with respect to whether their effects are useful. Thus, beneficial DNA changes do not happen more often simply because organisms could benefit from them. Moreover, even if an organism has acquired beneficial mutation during its lifetime, corresponding information will not flow back into DNA in the organism's germline. This is fundamental insight that Jean - Baptiste Lamarck got wrong and Charles Darwin got right. However, idea that mutations are random can be regarded as untrue if one considers the fact that not all types of mutations occur with equal probability. Rather, some occur more frequently than others because they are favor by low - level biochemical reactions. These reactions are also the main reason why mutations are inescapable property of any system that is capable of reproduction in the real world.

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* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Pathways to Therapeutics

Table

NameDiseaseMolecular DefectDonor CellAgeSex
ADAADA-SCIDGGG > AGG, exon 7 and Del(GAAGA) exon 10, ADA geneFibroblast3MMale
GDGaucher's disease type IIIAAC > AGC, exon 9, G-insertion, nucleotide 84 of cDNA, GBA geneFibroblast20YMale
DMDDuchenne muscular dystrophyDeletion of exons 45-52, dystrophin geneFibroblast6YMale
BMDBecker muscular dystrophyUnidentified mutation in dystrophin geneFibroblast38YMale
DS1Down syndromeTrisomy 21Fibroblast1Y,1MMale
PDParkinson's diseaseMultifactorialFibroblast57YMale
JDMJuvenile diabetes mellitusMultifactorialFibroblast42YFemale
SBDSShwachman-Bodian-Diamond syndromeIV2 + 2T > C and IV3 - 1G > A, SBDS geneBone marrow mesenchymal cells4MMale
HDHuntington's disease72 CAG repeats, huntingtin geneFibroblast20YFemale
LNScLesch-Nyhan syndrome (carrier)Heterozygosity of HPRT1Fibroblast34YFemale

Wellderly, there is only one harboring potential genetic gems; examining infectious disease survivors offers another promising avenue. Wherever there is a profound infectious disease infecting the community, looking at survivors enables you to look for resistance genes which may cast enormous light on the etiology of disease and potentially lead to new treatment, says neurologist John Collinge of University College London. Researchers, for example, are investigating drugs to fight the Ebola virus that target protein known as Niemann Pick type C. Genes that encode it, when mutate, cause rare version of Niemann Pick Disease that is usually fatal in childhood to people with two copies. But in animal studies, individuals with only one mutated copy of gene resist Ebola infection because viruses need a working version of protein to infect host cells. In other recent research, investigators have looked for gene mutations that protect against infection, or severe illness from influenza and other pathogens. In October, researchers with MalariaGEN international consortium identified a gene variant that affects blood cell surface receptor and protects against severe cases of malaria. Collinge and his colleagues have been studying survivors of more exotic epidemic: kuru, deadly neurological illness similar to Creutzfeld Jakob Disease. Like CJD, kuru is transmitted by misshapen proteins called prions, and, in the 1950s and 1960s, it spread rapidly among members of cannibalistic tribe in Papa New Guinea. When someone dies of kuru, ritualistic consumption of their body means that those participating in the ceremony would contract the disease too. In some villages, almost all women of childbearing age perish. But decades later, there were also survivorspeople who partaken in feasts and never got sick. In the early 1990s, Collinge began sequencing their genomes. Over the past two decades, hes revealed mutations in their prion protein gene, PRNP, that protect them from kuru. In those families with polymorphism, there is hardly any kuru despite very high levels of exposure, says Collinge. This year, Collinge and his colleagues report in Nature that mice with one of the mutations were protected from 18 different kinds of prion disease. This particular finding is incredibly powerful, says Collinge. We GO from 100 percent of mice dying to 0 percent. Now, researchers are working on determining the structure of protective risk and protection are really just flip sides of the same coin. Sekar Kathiresan prion proteins, which could shed light on how to mimic mutations in the rest of the human population, possibly leading to treatments for not just kuru but a variety of prion diseases. Ideally, discovery of protective mutation could inform development of drugs that mimic its molecular effects in the body. Inhibitors of CETP, Study by Barzilai, have been explored as cholesterol drugs, although none has reached the market.


What Is a Gene?

Sometimes scientists alter genes on purpose. For many years, researchers have altered genes in plants to produce other plants with special characteristics, such as increased resistance to disease and pests or ability to grow in difficult environments. We call this genetic engineering. Gene therapy is a promising new field of medical research. In gene therapy, researchers try to supply copies of healthy genes to cells with variant or missing genes so that good genes will take over. Viruses are often used to carry healthy genes into targeted cells because many viruses can insert their own DNA into targeted cells. But there are problems with gene therapy. Scientists still don't quite know what every gene in the human body does. Huge scientific efforts like the Human Genome Project and related projects have a complete map of the entire Human Genome, but it will take many more years to find out what each gene does and how they interact with one another. For most diseases, scientists don't know if and how genes play a role. Plus, there are major difficulties inserting normal genes into proper cells without causing problems for the rest of the body. There are also concerns that people might try changing genes for ethically troubling reasons, such as to make smarter or more athletic children. No one knows what the long - term effects of that kind of change will be. Still, for many people who have genetic diseases, gene therapy holds hope that they or their children will be able to live better, healthier lives.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

A Struggle Against Statistics

Table

Gene VariantEnvironmental ExposureRelative Risk (XP)Relative Risk (PKU)Relative Risk (emphysema)
AbsentAbsent1.01.01.0
PresentAbsent~1.01.0Modest
AbsentPresentModest1.0Modest
PresentPresentVery HighVery HighHigh

Wellderly, there is only one harboring potential genetic gems; examining infectious disease survivors offers another promising avenue. Wherever there is a profound infectious disease infecting the community, looking at survivors enables you to look for resistance genes which may cast enormous light on the etiology of disease and potentially lead to new treatment, says neurologist John Collinge of University College London. Researchers, for example, are investigating drugs to fight the Ebola virus that target protein known as Niemann Pick type C. Genes that encode it, when mutate, cause rare version of Niemann Pick Disease that is usually fatal in childhood to people with two copies. But in animal studies, individuals with only one mutated copy of gene resist Ebola infection because viruses need a working version of protein to infect host cells. In other recent research, investigators have looked for gene mutations that protect against infection, or severe illness from influenza and other pathogens. In October, researchers with MalariaGEN international consortium identified a gene variant that affects blood cell surface receptor and protects against severe cases of malaria. Collinge and his colleagues have been studying survivors of more exotic epidemic: kuru, deadly neurological illness similar to Creutzfeld Jakob Disease. Like CJD, kuru is transmitted by misshapen proteins called prions, and, in the 1950s and 1960s, it spread rapidly among members of cannibalistic tribe in Papa New Guinea. When someone dies of kuru, ritualistic consumption of their body means that those participating in the ceremony would contract the disease too. In some villages, almost all women of childbearing age perish. But decades later, there were also survivorspeople WHO partaken in feasts and never got sick. In the early 1990s, Collinge began sequencing their genomes. Over the past two decades, hes revealed mutations in their prion protein Gene, PRNP, that protect them from kuru. In those families with polymorphism, there is hardly any kuru despite very high levels of exposure, says Collinge. This year, Collinge and his colleagues report in Nature that mice with one of the mutations were protected from 18 different kinds of prion disease. This particular finding is incredibly powerful, says Collinge. We GO from 100 percent of mice dying to 0 percent. Now, researchers are working on determining the structure of protective prion proteins, which could shed light on how to mimic mutations in the rest of the human population, possibly leading to treatments for not just kuru but a variety of prion diseases. Ideally, discovery of protective mutation could inform development of drugs that mimic its molecular effects in the body. Inhibitors of CETP, Study by Barzilai, have been Explore as cholesterol drugs, although none has reached the market.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Effects of Mutations

Some mutations have a positive effect on the organism in which they occur. They are called beneficial mutations. They lead to new versions of proteins that help organisms adapt to changes in their environment. Beneficial mutations are essential for evolution to occur. They increase organisms ' changes of surviving or reproducing, so they are likely to become more common over time. There are several well - known examples of beneficial mutations. Here are just two: mutations in many bacteria that allow them to survive in the presence of antibiotic drugs. Mutations lead to antibiotic - resistant strains of bacteria. Unique mutation is found in people in small towns in Italy. Mutation protects them from developing atherosclerosis, which is a dangerous buildup of fatty materials in blood vessels. The individual in which mutation first appear has even been identify.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

1. Introduction

Evolution is a process by which populations of organisms change over generations. Genetic variations underlie these changes. Genetic variations can arise from gene mutations or from genetic recombination. These variations often alter gene activity or protein function, which can introduce different traits in organism. If a trait is advantageous and helps individuals survive and reproduce, genetic variation is more likely to be passed to the next generation. Over time, as generations of individuals with traits continue to reproduce, advantageous traits become increasingly common in population, making population different than ancestral one.S Sometimes population becomes so different that it is considered a new species. Not all mutations lead to evolution. Only hereditary mutations, which occur in egg or sperm cells, can be passed to future generations and potentially contribute to evolution. Some mutations occur during personas lifetime in only some bodyas cells and are not hereditary, so natural selection cannot play a role. Also, many genetic changes have no impact on the function of genes or proteins and are not helpful or harmful. In addition, environment in which populations of organisms live is integral to the selection of traits. Some differences introduced by mutations may help organisms survive in one setting, but not in other example, resistance to certain bacteria is only advantageous if that bacteria is found in a particular location and harms those who live there. So why do some harmful traits, like genetic diseases, persist in populations instead of being removed by natural selection? There are several possible explanations, but in many cases, answer is not clear. For some conditions, such as neurological condition Huntington disease, signs and symptoms do not occur until after person has children, so gene mutation can be passed on despite being harmful. For other harmful traits, phenomenon called reduce penetrance, in which some individuals with disease - associate mutation do not show signs and symptoms of condition, can also allow harmful genetic variations to be passed to future generations. For some conditions, having one mutated copy of gene in each cell is advantageous, while having two mutated copies causes disease. The best - studied example of this phenomenon is sickle cell disease: Having two mutated copies of HBB gene in each cell results in disease, but having only one copy provides some resistance to malaria. This disease resistance helps explain why mutations that cause sickle cell disease are still found in many populations, especially in areas where malaria is prevalent.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Sickle Cell

Sickle cell disease is a group of disorders that affect hemoglobin, molecule in red blood cells that delivers oxygen to cells throughout the body. People with this disease have atypical hemoglobin molecules called hemoglobin S, which can distort red blood cells into a sickle, or crescent, shape. Signs and symptoms of sickle cell disease usually begin in early childhood. Characteristic features of this disorder include low number of red blood cells, repeat infections, and periodic episodes of pain. The severity of symptoms varies from person to person. Some people have mild symptoms, while others are frequently hospitalized for more serious complications. Signs and symptoms of sickle cell disease are caused by sickling of red blood cells. When red blood cells sickle, they break down prematurely, which can lead to anemia. Anemia can cause shortness of breath, fatigue, and delayed growth and development in children. Rapid breakdown of red blood cells may also cause yellowing of eyes and skin, which are signs of jaundice. Painful episodes can occur when sickled red blood cells, which are stiff and inflexible, get stuck in small blood vessels. These episodes deprive tissues and organs, such AS lungs, kidneys, spleen, and brain, of oxygen - rich blood and can lead to organ damage. A particularly serious complication of sickle cell disease is high blood pressure in blood vessels that supply lungs, which can lead to heart failure. Pulmonary hypertension occurs in about 10 percent of adults with sickle cell disease. Sickle cell disease affects millions of people worldwide. It is most common among people whose ancestors come from Africa; Mediterranean countries such AS Greece, Turkey, and Italy; Arabian Peninsula; India; and Spanish - speaking regions in South America, Central America, and parts of the Caribbean. Sickle cell disease is the most common inherited blood disorder in the United States, affecting an estimated 100 000 Americans. The disease is estimated to occur in 1 in 500 African Americans and 1 in 1 000 to 1 400 Hispanic Americans. Mutations in HBB gene cause sickle cell disease. The Hbb gene provides instructions for making one part of hemoglobin. Hemoglobin consists of four protein subunits, typically, two subunits called alpha - globin and two subunits called beta - globin. Hbb gene provides instructions for making beta - globin. Various versions of beta - globin result from different mutations in the HBB gene. One particular HBB gene mutation produces an abnormal version of beta - globin known as AS hemoglobin S. Other mutations in the HBB gene lead to additional abnormal versions of beta - globin such AS hemoglobin C and hemoglobin E. Hbb gene mutations can also result in unusually low levels of beta - globin; this abnormality is called beta thalassemia. In people with sickle cell disease, at least one of the beta - globin subunits in hemoglobin is replaced with hemoglobin S. In sickle cell anemia, which is the most common form of sickle cell disease, hemoglobin S replaces both beta - globin subunits in hemoglobin. In other types of sickle cell disease, just one beta - globin subunit in hemoglobin is replaced with hemoglobin S.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Some Examples of Beneficial Mutation

The vast majority of mutations are neutral or deleterious. Extensive study of such mutations has explained genetic diversity in many populations and has been useful for inferring population parameters and histories from data. Yet beneficial mutations, despite their rarity, are what cause long - term adaptation and can also dramatically alter genetic diversity at link sites. Unfortunately, our understanding of their dynamics remains poor by comparison. When beneficial mutations are rare and selection is strong, positive selection results in succession of selective sweeps. Mutations occur, spread through the population due to selection, and soon fixes. Some time later, another such event may occur. This situation is sometimes called strong - selection weak - mutation regime. To make its character clear, we refer to it as a successional - mutations regime: between sweeps, there is a single ruling population. In this regime, effect of positive selection on patterns of genetic variation is reasonably well understood. Selective sweep reduces genetic variation in regions of genome link, over timescale of sweep, to site at which beneficial mutation occurs: other mutations in these regions hitchhike to fixation. Successional - mutation behavior typically occurs in small - to moderate - sized populations in which beneficial mutations are sufficiently rare. However, different regimes occur in larger populations, in which beneficial mutations occur frequently. When beneficial mutations are common enough that many mutant lineages can be simultaneously present in the population, selective sweeps will overlap and interfere with one another. If, in addition, selection is strong enough that it is not dominated by random drift, we have a strong - selection strong - mutation regime. For clarity, we refer to this as concurrent - mutations regime. Effects of concurrent mutations in asexual populations are the focus of this article. As we will see, concurrent - beneficial - mutations regime is not an unusual special case: many viral, bacterial, and simple eukaryotic populations likely experience evolution via multiple concurrent mutations. In populations that contain many different beneficial mutants, there will be substantial variation in fitness within the population. This variation will be acted on by selection. But in the absence of new mutations, variation will soon disappear. Thus, traditional approach to evolution of quantitative traitsto assumes that genetic variation always exists fails badly. New mutations are crucially needed to maintain variation on which further selection can act. Thus, to understand adaptation when multiple mutations are involve, it is essential to analyze the interplay between selection and new beneficial mutations, especially how the latter maintain variation act on the former. Understanding this beneficial mutation - selection balance and resulting dynamics is the primary goal of this article. Both successional - and concurrent - mutation regimes require that selection dominate drift except while mutants are very rare. Qualitatively different regimes occur with weakly beneficial mutations: these do not sweep in the traditional sense because drift dominates their dynamics. This weakly beneficial regime most readily occurs in small populations, where selective forces cannot overcome drift, or when considering mutations of very small effect, such as those that affect synonymous codon usage.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Beyond good and bad

But we also know that categorising mutations as good or bad can sometimes be very difficult. Often it depends on context,. For example, whether mutation helps organism use particular food source or fight off disease present during its lifetime. And some mutations can be beneficial if just one copy is inherit, but harmful if two copies are inherit. One example of gene mutation subject to this kind of balancing selection is sickle cell disease. People with sickle - cell disease have gene mutation that produce an altered form of haemoglobin, protein in red blood cells that carry oxygen around the body. Altered haemoglobin produces long sickle - shaped blood cells that can get stuck in small blood vessels. This causes pain in the chest and joints, as well as anaemia, increasing the risk of infections and other problems. Yet despite these potentially devastating health effects, disease is relatively common in certain countries. An estimated 300 000 infants who inherit two copies of sickle - cell gene mutation are born with the disease every year, mostly in Nigeria, Democratic Republic of Congo, and India. This is because people with one copy of mutation are resistant to malaria, and so are more likely to survive to adulthood and pass mutated gene on to their children. So, even though having sickle disease is an evolutionary disadvantage, unaffected carriers of gene mutation have survival advantage in countries where malaria was rife. A recent US study suggests that all people living with the condition today descended from a single ancestor who lived around 7 300 years ago in either Sahara or west - central Africa. This shows how a single mutation can spread to many, many individuals in the population if it bestows significant benefit, even if it also has potential to do harm. Similarly, there is evidence that a single copy of cystic fibrosis gene mutation may have provided our ancestors with resistance to cholera, and that carriers of Tay - Sachs disease have tuberculosis resistance. Better understanding of the effects of mutations could play a big role in treating disease. For example, studying mutation rates in different cell types could shed light on how cancer arises in different body tissues. And understanding bacterial mutation rates could help scientists fight microbes that have evolved resistance to antibiotics. This will eventually help usher in a new era of medicine, in which many diseases will be diagnosed and treated with the help of genetic information. And that get to be good.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

8. Super Vision

As far AS color Vision GO, humans have pretty keen sight relative to other animals. Having three types of cones present in our eyes gives us an evolutionary advantage as hunter - gatherers by better enabling us to spot fruits and berries than animals with only two types of cones. Color blindness is a condition caused by gene mutation that disables one of these cones. It is much more common in males, since genes responsible for detecting colors red and green are found only on the X chromosome. Because men only have one X copy, if mutations on the X chromosome occur theyre more likely to exhibit altered traits than women who have two X chromosomes. But what if instead of disabling one of the cones, mutation increased the range of colors it was able to detect? If mutation occur in man it would likely only result in slightly shifted color spectrum. But in woman, if one of her X chromosomes had this mutation and the other one didnt, it would hypothetically result in her possessing the ability to see an increased range of colors undetectable by most people. According to a study published in Journal of Vision, roughly 12% of women have this sort of super Vision, although scientists have officially labelled condition tetrachromacy.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Sources

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

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