Strength of the Homo Sapiens Gene Pool
Overview
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The technological and medical advancements that humans have made has increased our life spans and improved the quality of life for individuals who are not very biologically fit due to medical conditions. For example, the MMR (measles, mumps and rubella) vaccine saved an estimated 17.1 million lives between 2000 to 2014. Therefore, without that vaccine, natural selection would have acted against those individuals who contracted measles, mumps or rubella and they would not have survived to reproductive age. The MMR vaccine enabled 17.1 million people to survive and possibly reproduce to pass their alleles to the next generation.
In addition in the 'Extinction Events' page, the effects of interbreeding within the royal family was discussed. This interbreeding increased the amount of males expressing the x-linked recessive trait, haemophilia in their phenotype. For example, Queen Victoria's 8th child, Prince Leopold, Duke of Albany, had haemophilia. Due to this condition, any minor bruise or cut could cause him to die. But at the age of 31, he died from a minor fall. Nowadays, haemophilia can be treated with blood transfusions and infusions of a clotting factor into the affected individuals blood (Aronova, 2003). Therefore, haemophiliacs may be more likely to survive, reproduce and pass their alleles to the next generation. Therefore, whilst the gene pool of humans is genetically diverse and therefore strong, the effects of natural selection are slowing down and enabling individuals who are not biologically fit to survive and reproduce. Thus, the allele frequencies for genetic conditions is increasing in our gene pool. |
Stem Cell Differentiation
Stem cells are obtained from embryos or the placental umbilical cord of the mother. Stem cells are able to differentiate into any type of cell and can therefore be used to replace damaged or diseased cells with healthy, functioning ones. Therefore, stem cell differentiation in the future will allow individuals who are biologically less fit (because they have unfavourable phenotypic traits) to survive. reproduce and pass their alleles to the next generation. Therefore, this medical advancement will further allow humans to slow down the process of natural selection and increase the allele frequencies for unfavourable phenotypes in the population.
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Genetic Screening
Genetic screening can be used to identify whether an embryo has chromosomal abnormalities or inherited conditions. Genetic screening has the potential to change the gene pool of Homo sapiens since the parents may choose to terminate the pregnancy or the affected individuals may choose to not have children. Therefore, genetic screening further slows down the rate of natural selection.
In addition, in vitro fertilisation allows parents to select desirable traits by fertilising specific sperm and eggs with the appropriate alleles. This results in the offspring having genotypes composed of favourable alleles and therefore may be biologically fitter than other individuals. This method will increase the rate of natural selection, but may decrease the amount of genetic diversity within the Homo sapien gene pool if it becomes commonplace. |
Gene Therapy
Gene therapy is a method used by humans to intervene in evolutionary processes. Gene therapy involves the insertion of genes into an individual who has a genetic condition to replace the defective alleles with functioning ones.
Gene therapy has been used to treat individuals with cystic fibrosis, which has enabled the affected individuals to live longer and potentially reproduce to pass their alleles to the next generation. Since gene therapy alters the DNA of somatic (body) cells, the individual is treated, but their germline (reproductive) cells still contain the DNA with the faulty alleles. Therefore, the faulty alleles for cystic fibrosis can inherited by offspring and the frequency of alleles for this chronic illness may increase within the Homo sapien gene pool and slow down the rate of natural selection.
Gene therapy has been used to treat individuals with cystic fibrosis, which has enabled the affected individuals to live longer and potentially reproduce to pass their alleles to the next generation. Since gene therapy alters the DNA of somatic (body) cells, the individual is treated, but their germline (reproductive) cells still contain the DNA with the faulty alleles. Therefore, the faulty alleles for cystic fibrosis can inherited by offspring and the frequency of alleles for this chronic illness may increase within the Homo sapien gene pool and slow down the rate of natural selection.
Bacterial Transformations
Bacterial transformations requires inserting a gene of interest into the plasmid of a bacterium to form a recombinant plasmid. The transformed bacteria then reproduce, all of which will express that gene. Bacterial transformations can be used to treat conditions, such as diabetes because the bacteria can be transformed to synthesise the protein insulin. This technique also influences the strength of the human gene pool since it enables individuals with diabetes to live longer and potentially reproduce. Thus, bacterial transformations is also enabling humans to slow down the rate of natural selection in our species.
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Overall
In my personal opinion, some of these medical and technological advancements are currently amazing since they have the ability to save many lives. However, the medical technology of in vitro fertilisation to produce 'designer babies' raises many ethical issues that I do not believe are right. Furthermore, I believe that techniques, such as gene therapy could end up having severe implications for our species because it would allow the allele frequencies of genetic conditions to increase in our population.
In addition, humans are constantly fighting bacterial infections with antibiotics, However, scientists have estimated that by 2050, around 10 million people may die every year due to a superbug. A superbug is a strong strand of bacteria that has become immune to the current antibiotics that we have invented. These superbugs will make infections incurable unless we are able to produce new antibiotics to target that specific superbug. Therefore, minor operations and infections could become life-threatening. The over-use of antibiotics in our society is what has caused these superbugs to arise (Lambert, 2016). Therefore, even though medical advancements have currently saved millions of lives, eventually we may be unable to intervene with evolutionary processes, which would weaken the Homo sapien gene pool.
In addition, humans are constantly fighting bacterial infections with antibiotics, However, scientists have estimated that by 2050, around 10 million people may die every year due to a superbug. A superbug is a strong strand of bacteria that has become immune to the current antibiotics that we have invented. These superbugs will make infections incurable unless we are able to produce new antibiotics to target that specific superbug. Therefore, minor operations and infections could become life-threatening. The over-use of antibiotics in our society is what has caused these superbugs to arise (Lambert, 2016). Therefore, even though medical advancements have currently saved millions of lives, eventually we may be unable to intervene with evolutionary processes, which would weaken the Homo sapien gene pool.
Strength of Other Species Gene Pools
Selective Breeding
Selective breeding is another technique in which humans have intervened with evolutionary processes. Selective breeding entails humans selecting certain animals with desirable traits to breeds so that the offspring produced express the desired trait. Selective breeding not only increases the allele frequency for the desirable traits, but also the traits that are linked (on the same chromosome as the desirable traits). This technique increases the number of homozygous organisms and decreases the amount of heterozygous organisms, thus causing a decrease in the genetic diversity of the species. A lowered genetic diversity makes a population more susceptible to selective pressures and therefore increases the species chances of extinction.
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Cloning
A clone is a genetically identical copy of an organism. Cloning is another form of human intervention in evolutionary processes as it leads to a loss of genetic diversity within the population of the species being cloned. Therefore, cloning could make species more likely to become extinct as their gene pool would become very weak. Cloning in humans could provide a treatment for autoimmune, degenerative or cancerous diseases as the diseased tissue could be replaced with cultured tissue.
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Deforestation
Deforestation is the destruction of forests in order to clear land for humans to use or to make paper. Between 1990 and 2000, Australia lost an average of 325,900 hectares of forest every year. Deforestation is not only destroying millions of hectares of forests every year around the world, but it's destroying the organisms that inhabit those forests. The trees within forests provide us with oxygen and reduces the amount of carbon dioxide in the atmosphere. Therefore, if we continue to obliterate our forests, there will be a higher amount of carbon dioxide in the atmosphere. When this carbon dioxide is absorbed by seawater, the pH of the ocean is lowered, causing the ocean to become more acidic. Calcifying species, such as oysters, clams, sea urchins, shallow water corals, deep sea corals and calcareous plankton, may be dramatically effected by ocean acidification. If these shelled organisms are jeopardised, the entire food web may be endangered. This would not only destroy Earth's ecosystems, but also our economy since the seafood industry provides many individuals with jobs.
In Australia, for every tree planted, 100 trees are bulldozed. Humans often replace these sites of destruction with factories, shopping centres or housing estates to facilitate for our growing population. Fossil fuels are burnt to provide electricity to these establishments. When fossil fuels combust, sulfur dioxides and nitrogen dioxides are released into the atmosphere, which react with oxygen to create mild solutions of sulfuric and nitric acid. This causes acid rain to form which causes severe environmental problems, such as lowering the pH of waterways, which could make entire ecosystems susceptible to extinction. Furthermore, acid rain destroys forests at high altitudes by replacing vital nutrients within the soil with aluminium, preventing the plants from absorbing water. This destroys the leaves and bark of the plant, whilst stunting their growth. Subsequently, the plants are more susceptible to disease and have a lowered ability to withstand cold temperatures and insects.
Therefore, not only are humans destroying Earth and the unique organisms that inhabit it, we are lowering the genetic diversity of a variety of animal and populations and increasing their chances of extinction. If we continue to destroy our planet, we may end up destroying ourselves.
In Australia, for every tree planted, 100 trees are bulldozed. Humans often replace these sites of destruction with factories, shopping centres or housing estates to facilitate for our growing population. Fossil fuels are burnt to provide electricity to these establishments. When fossil fuels combust, sulfur dioxides and nitrogen dioxides are released into the atmosphere, which react with oxygen to create mild solutions of sulfuric and nitric acid. This causes acid rain to form which causes severe environmental problems, such as lowering the pH of waterways, which could make entire ecosystems susceptible to extinction. Furthermore, acid rain destroys forests at high altitudes by replacing vital nutrients within the soil with aluminium, preventing the plants from absorbing water. This destroys the leaves and bark of the plant, whilst stunting their growth. Subsequently, the plants are more susceptible to disease and have a lowered ability to withstand cold temperatures and insects.
Therefore, not only are humans destroying Earth and the unique organisms that inhabit it, we are lowering the genetic diversity of a variety of animal and populations and increasing their chances of extinction. If we continue to destroy our planet, we may end up destroying ourselves.
Finding Another Earth
Not only have humans destroyed the surface of Earth, but we have also contaminated the Earth's atmosphere with hundreds of thousands of pieces of debris or "space junk." This debris orbits the Earth and includes nonfunctional spacecraft, abandoned launch vehicle stages, mission-related debris and fragmentation debris. More than 20,000 pieces of debris circling the Earth is larger than the size of a softball. This debris can travel at a speed of 17,500 mph, which could destroy a satellite or spacecraft. Around 500,000 pieces of space junk are approximately the size of a marble. Since this debris is so small, NASA are unable to track it (Garcia, 2016). The small debris poses a severe threat to space missions as it cannot be avoided and could cause horrendous damage the space-craft
NASA are currently trying to discover planets that are similar to Earth, so that eventually we may be able to escape the damage that we have caused to Earth. In 2015, NASA discovered a new exoplanet, Kepler-452b, using the Kepler space telescope.The habitable zone is the band of congenial temperatures for planetary orbits. Kepler-452b is located within the right temperature of the habitable zone around it's sun-like star to make it similar to the Earth-sun system of our solar system. Kepler-452b is approximately one-and-a-half times the diameter of Earth, orbiting a star that is very similar to our own sun (Brennan, 2015). Eventually, humans may be able to develop the technology that could enable us to inhabit another planet and escape the destruction that we have inflicted on Earth.
NASA are currently trying to discover planets that are similar to Earth, so that eventually we may be able to escape the damage that we have caused to Earth. In 2015, NASA discovered a new exoplanet, Kepler-452b, using the Kepler space telescope.The habitable zone is the band of congenial temperatures for planetary orbits. Kepler-452b is located within the right temperature of the habitable zone around it's sun-like star to make it similar to the Earth-sun system of our solar system. Kepler-452b is approximately one-and-a-half times the diameter of Earth, orbiting a star that is very similar to our own sun (Brennan, 2015). Eventually, humans may be able to develop the technology that could enable us to inhabit another planet and escape the destruction that we have inflicted on Earth.