Eugenics
Related Terms
Conventional eugenics, designer babies, DNA sequencing, eugenics, gene splicing, gene therapy, genetic engineering, in vitro fertilization, modern eugenics, mutation detection, natural eugenics, PCR, personal genomics, polymerase chain reaction, preimplantation diagnosis, prenatal detection, real-time polymerase chain reaction, recombinant DNA technology, RT-PCR, transfection, transformation.
Background
Eugenics is the study of factors or the science of refining the genetic structure of an organism in order to improve its hereditary characteristics for future generations. The improvement of inherent qualities through genetic means is applicable to plants, animals, and particularly to humans. An example would be changing the genetic characteristics of future generations in such a way that they would not be vulnerable (susceptible) to certain diseases.
The term ''eugenics'' was coined by Francis Galton in 1883, from the Greek word eugenes, meaning ''well-born'' or ''hereditarily endowed with noble qualities.'' It may be thought of as a social, political, and scientific movement, generally referring to humans, and it has been the source of much controversy and ethical debate. While the philosophical argument in favor of eugenics is that it lessens human suffering by preventing the spread of negative genetic traits, it is generally regarded as a violation of human rights. Forced sterilization in individuals (via birth control techniques) who were thought to have negative genetic traits was instituted in the first half of the 20th Century. The Nazi eugenics program took the form of the Holocaust, the planned extermination of European Jews and others during World War II.
Genes: Genes (deoxyribonucleic acid or DNA) are considered the building blocks of life because they provide instructions for all cells in the body. Genes, which are located inside cells, control an organism's development and function by instructing cells to make new molecules (usually proteins). DNA is a long thread-like molecule made up of large numbers of nucleotides. Nucleotides or bases are molecules composed of a nitrogen-containing base, a 5-carbon sugar, and one or more phosphate groups. Long strands of nucleotides form nucleic acids. The sequence of bases in DNA serves as the carrier of genetic (hereditary) information. Alleles are two or more alternate forms of a gene that may occur alternatively at a given site on a chromosome. Chromosomes carry hereditary information in the form of genes. Humans have 22 pairs of chromosomes (autosomes) and a pair of sex chromosomes (X and Y chromosomes).
Eugenics may be conceptually divided into two categories: (1) positive eugenics, which is aimed to encourage reproduction in persons presumed to have desirable inheritable traits; and (2) negative eugenics, aimed at discouraging reproduction by persons having genetic defects or presumed to have undesirable inheritable traits. Eugenics has existed throughout history in three major forms: (1) natural, (2) conventional, and (3) modern.
Natural eugenics: This naturally occurring type of eugenics is known as evolution by natural selection. In the evolutionary process of all organisms and species, the weaker members of a species do not procreate, as they die from various factors that would not kill the stronger members. Even if they survive, the weaker or inferior members of a species are not likely to procreate because most animals naturally prefer to mate with members of their own species who have attractive features that reflect health, reproductivity, longevity, etc. Thus, the genetic makeup and inferior characteristics of weaker members are consequently removed from the gene pool of that species.
Conventional eugenics: Conventional eugenics experimentation, which involves selective breeding in order to accelerate the natural trend of evolution, started with the ancient Greeks. Farmers and animal herders have been applying conventional eugenics for centuries. For example, a breeder decides which animals have the most advantageous characteristics and only allows those animals to reproduce, thereby removing the inferior organisms from the gene pool without waiting for the evolutionary process.
Modern eugenics: The aim of this emerging form of eugenics is unlike natural eugenics (natural selection) or conventional eugenics (selective breeding). Modern eugenics involves the direct manipulation of the genetic material of an organism, which may completely remove the evolution of living beings from the reproductive process. This is completed in a test tube by genetic engineering (in vitro fertilization). Genetic engineering is the artificial modification of the genetic makeup of an organism or population of organisms to achieve a planned and desired result.
Bioethics: With the advent of modern eugenics, bioethical laws have also emerged all over the world in order to avoid the indiscriminate use of genetic technology and its potential abuse in social and political fields. For example, the Genetic Information Nondiscrimination Act (GINA) serves to protect people in the United States from discrimination based on their genetic information for health insurance and employment purposes. Several federal authorities, such as the U.S. Food and Drug Administration (FDA), the U.S. Environmental Protection Agency (EPA), and the Department of Agriculture (USDA), are involved in regulating genetically engineered products.
Methods
General: Eugenics is the study of factors or the science of refining the genetic structure of an organism in order to improve its hereditary characteristics for future generations. Modern eugenics involves a wide spectrum of nucleic acid detection and manipulation techniques, such as mutation detection, genetic engineering, gene therapy, and personal genomics.
Mutation detection: Deoxyribonucleic acid (DNA) is a long thread-like molecule made up of large numbers of nucleotides or bases. Nucleotides are molecules composed of a nitrogen-containing base, a 5-carbon sugar, and one or more phosphate groups. The sequence of bases in DNA serves as the carrier of genetic (hereditary) information. Variations in DNA sequences are known as mutations, which may be associated with the development of certain diseases or which may increase the susceptibility of a person to certain disorders. Several genetic analysis techniques are available to detect gene mutations such as real-time polymerase chain reaction (RT-PCR), DNA sequencing, and DNA microarrays.
Polymerase chain reaction (PCR) is an efficient and sensitive laboratory technique used to amplify (by replication) a specific sequence of DNA into billions of copies, in the presence of sequence-specific oligonucleotide primers and the DNA polymerase enzyme. An oligonucleotide primer is a sequence of nucleotides (usually 20-50 bases) that are complementary to a specific DNA sequence, and which assists in DNA replication. RT-PCR is a PCR-based laboratory technique, which enables the simultaneous detection and quantification (the measurement of the amount) of a specific sequence in a DNA sample. This follows the general principle of the PCR with a key difference, that is, the amplified or increased amount of DNA can be viewed and quantified as it accumulates in the reaction in real time, after each amplification cycle.
DNA sequencing is a process by which the precise sequence of nucleotides in a sample of DNA is determined. It serves as a scanning method for single nucleotide polymorphisms (SNPs), DNA sequence variations that occur when a single nucleotide in the genome sequence is altered. SNPs are often associated with the development of several diseases.
DNA microarrays or chips are miniaturized chemical reaction areas used to test DNA/RNA (ribonucleic acid) fragments by immobilizing the target sequence following hybridization with a probe sample. The hybridized probe-target can be detected with a fluorescent marker on the surface of the chip. The fluorescent color emitted is scanned, and the data is analyzed by a computer, identifying the target sequence. Hybridization refers to the binding of the probe with the target complementary sequence, forming a hybrid. The advantage of microarray technology is that multiple markers or thousands of nucleic acid sequences may be detected and identified in a single reaction, thus assisting in timely treatment decisions and the management of disease(s).
Genetic engineering: Genetic engineering is a deliberate modification of the genetic makeup of an organism or population of organisms to achieve a planned and desired result. It involves the use of recombinant DNA, molecular cloning, and transformation. The result is a genetically modified plant (e.g., crops) or organism.
Recombinant DNA technology refers to DNA that has been altered by joining genetic material from two or more different sources, such that the altered DNA becomes part of the genetic makeup of the host organism and is replicated within the same organism. It usually involves cutting the gene from one organism (gene splicing) and putting it into the genome of a different organism (transplanting), generally of a different species.
Molecular cloning is the biological amplification of a specific DNA sequence by replicating the host cell of an organism that has been transformed or transfected. Transformation refers to any alteration in the genome of the cell due to the uptake, incorporation, or expression of foreign genetic material (i.e., DNA). Transfection is the process of introducing foreign material into eukaryotic cells (complex structures within membranes, e.g., in animals and plants) using a virus vector or other methods of transfer. For the genes to be transfected, they must be delivered inside a carrier, called a vector. Viruses that are grown in a laboratory are the most commonly used vectors.
Gene therapy: Gene therapy is an experimental procedure that involves inserting human genes into a patient in order to treat or prevent inherited disorders and some types of cancer. Several methods of gene therapy are currently being studied, such as the replacement of a gene, the inactivation of a gene, and the insertion of a new gene.
The replacement of a gene involves the insertion of a normal gene into a patient to replace either a missing gene or a mutated gene that is causing an inherited disorder. For instance, a common tumor suppressor gene called P53 normally prevents tumors from growing in the body. Several types of cancer have been linked to either a missing or inactive P53 gene. Researchers hope that by replacing this specific gene, it may help treat or prevent cancer. This is because researchers believe the P53 gene may help the body fight tumors.
Inactivation of a gene involves turning off mutated genes to treat or prevent certain diseases. For example, certain genes called oncogenes are abnormal genes that have been shown to promote cancerous growths. It has been suggested that inactivating these genes may help treat or prevent cancer. Synthetic oligonucleotides have been used to interfere with the patient's mutated gene, preventing or limiting its expression and thereby preventing the development of certain diseases.
The insertion of a new gene has been done to help the body fight certain diseases. For instance, cancer cells often mutate and become resistant to chemotherapy and radiation therapy. Researchers hope that cancer treatment can be made more effective by inserting genes that do not mutate into drug-resistant genes during chemotherapy, thereby enabling the cells to respond to treatment again.
Research
Sickle cell anemia: Researchers have successfully used gene therapy to treat sickle cell anemia in mice. Sickle cell anemia is an inherited disorder that causes blood cells to have an abnormal shape, which may lead to blood clots. Researchers have inserted into mice a new gene that counteracts the mutated gene that causes sickle cell anemia. However, additional research is needed to determine if this therapy is safe and effective in humans. Thus, the development of such a gene in humans may help prevent future generations from developing sickle cell anemia.
Cancer: Many different types of gene therapies have been studied as possible ways to treat or prevent various types of cancer. Hundreds of human medical trials are currently underway to evaluate the safety and effectiveness of gene therapy in a wide variety of cancer patients. Although early research in this area is promising, additional research is needed to determine its safety and effectiveness.
Vaccines: A vaccine is a preparation that produces active immunity in the body to fight specific infections. Researchers are looking into ways of delivering vaccines through genetically modified foods (GMFs). For instance, researchers are trying to develop bananas that can produce human vaccines against infectious diseases such as hepatitis B (a viral infection). Researchers are also working to develop vaccines in other plants (delivery candidates) including tomatoes and potatoes. Scientists hope that these plants will be much easier to ship, store, and administer than traditional vaccines, which need to be refrigerated.
Personal genomics: Personal genomics is the study of the structure and function of genes using various genetic analytical tools, so that these tools may be utilized for personalized medicine (where patients can take genotype-specific drugs for medical treatment). Genotype refers to genes contained in a cell; the cells used may be cancer cells or any other cell to which the drug is targeted. This involves partial or whole genome sequencing for the detection of mutations of individual genes, and using this information to decide on medical treatments that are appropriate for a particular individual.
An example of personalized medicine is choosing a drug specific to the patient that would maximize the probability of obtaining the desired result and minimizing the probability of side effects. As personal genomics may involve the manipulation of genes and genetic characteristics at an individual level, it may affect future generations by changing their characteristics or susceptibility to a disease or disorder. Research is continuing in this area.
Implications
General: Eugenics is the study of factors or the science of refining the genetic structure of an organism in order to improve its hereditary characteristics for future generations. Modern eugenics, with the development of nucleic acid analysis and manipulation techniques, has a wide spectrum of applications and has arrived at a critical juncture in the evolution of the human race.
Genetic screening: A permanent variation in the deoxyribonucleic acid (DNA) sequence of a gene is called a mutation. These mutations in humans may be involved with the development of inheritable diseases or the increased susceptibility of individuals to certain diseases such as cancer, heart diseases, Parkinson's disease (a progressive degenerative disorder of the nervous system). Genetic screening to identify these mutations may help in preventing the development of these diseases or disorders to a certain extent, thereby reducing or removing the impaired genes from a population's gene pool.
Inheritable conditions such as Tay-Sachs disease, cystic fibrosis, and Canavan disease, are more prevalent in Ashkenazi Jewish populations. Thalassemia, an inheritable blood disorder, is very common in Cyprus. These life-threatening genetic disorders may be detected with the help of mutation analysis techniques, such as polymerase chain reaction (PCR) and DNA sequencing. PCR is a laboratory technique conducted to amplify (by replication) a specific sequence of DNA into billions of copies. DNA sequencing is a process in which the precise sequence of nucleotides in a sample of DNA is determined. Thus, mutation analysis along with genetic counseling may help in evaluating the probability of having children with the disorder, based on known risk factors, and in making suitable decisions. However, it is important to realize that genetic tests cannot guarantee accuracy, as there is always a risk of terminating a healthy fetus as well as allowing an abnormal fetus to develop.
Preimplantation genetic diagnosis (PGD): PGD is also known as embryo screening and involves procedures that are performed on embryos prior to implantation. Implantation refers to an event that occurs early in pregnancy in which the embryo adheres to the wall of the uterus. PGD requires in vitro fertilization, where eggs are removed from the mother's ovary and fertilized by sperm in a Petri dish, creating a set of human embryos.
When these embryos are 3-5 days old, they comprise eight cells. One of those cells is removed and genetically tested for diseases, such as intestinal cancer, breast cancer, Down syndrome, or cystic fibrosis, to determine if the embryo is at risk. Researchers can also determine whether the tiny embryo is a boy or a girl. Based on this information, parents can decide which embryos they want to transfer back to the uterus for implantation (embryo selection). Parents choose the traits or embryos they want; the ones they do not choose are not necessarily defective. PGD gives rise to strong and often-conflicting views about the social acceptability of the procedure, and it involves ethical issues.
For example, in Germany the use of PGD is illegal, whereas in other countries, it is permitted by law but governed by regulatory authorities, such as the Human Fertilisation and Embryology Authority (HFEA) in the United Kingdom.
Therapeutic drugs: Genetic engineering refers to the deliberate manipulation of the genetic make up of an organism or population of organisms to achieve a planned and desired result. Genetic engineering technology has provided the means for the large-scale production of proteins, which has found wide applications in medical therapeutics, such as the production of insulin, growth hormone, interferon, etc. Insulin, a polypeptide hormone, is used in the treatment of diabetes mellitus. Hormones are chemical substances normally produced in the body that regulate growth and metabolism. Diabetes mellitus is a long-term disease with serious complications, characterized by excess sugar (glucose) in the blood. Interferons are proteins that are part of the body's immune system that fight infections (e.g., viral infections).
Gene therapy: Gene therapy is an experimental procedure that involves inserting human genes into a patient in order to treat or prevent inherited disorders. Some examples include erythropoietin (EPO) genes and vascular endothelial growth factor (VEGF) gene. EPO is a hormone that boosts the production of red blood cells and is used in the treatment of anemia associated with long-term kidney disease, cancer of the bone marrow, the use anti-cancer drugs (chemotherapy), etc. Synthetic EPO from introduced genes is identical to naturally existing EPO. VEGF is used in the treatment of peripheral atherosclerotic disease, a painful disease that results in the constriction of blood vessels to the limbs, and which can result in the loss of a limb. Introduction of the VEGF gene boosts VEGF levels, which widens blood vessels. EPO and VEGF gene therapy are misused in athletes to enhance their performance.
Genetically modified foods: Scientists have been able to change the genetic makeup of plants and animals that are used for human consumption. These food products are called genetically modified foods (GMFs) or genetically modified organisms (GMOs). Some examples of genetic modification, where genes of animals have been changed include, chickens and cows, so as to increase the animal's size and its productivity of eggs and milk, respectively, and to improve its health and feed efficiency. Other GMFs include crops (such as rice, corn, soybeans, sweet potatoes, apples, tomatoes, cantaloupes, and other fruits and vegetables) to improve taste and quality (including color and size), reduce maturation time, increase nutrition, increase tolerance to extreme temperatures, and improve resistance to disease, pests and herbicides.
Limitations
Deoxyribonucleic acid (DNA) microarrays, or DNA chips, are miniaturized chemical reaction areas used to test DNA/RNA (ribonucleic acid) fragments. With this analytical technique, hundreds or thousands of genes and mutations can be tested at the same time. This technique offers tremendous promise for more accurate, sensitive, and efficient genetic testing. However, this powerful technology dramatically increases the number and scope of ethical concerns accompanying each individual test request, as well as issues concerning informed consent, confidentiality, clinical utility, discrimination, stigmatization, ethnic and population impact, and reimbursement.
Genetic engineering is a deliberate manipulation of the genetic makeup of an organism or population of organisms to achieve a planned and desired result. This technology carries potential dangers such as the creation of new allergens and toxins, the evolution of new weeds and other poisonous or harmful vegetations, harm to wildlife, and the creation of environments favorable to the development of molds and fungi. Some scientists have expressed concern that new disease-causing organisms and increased antibiotic resistance could result from the use of genetically modified organisms in the food chain. Antibiotic resistance refers to the ability of a bacteria or microorganism to survive and reproduce in the presence of an antibiotic previously thought to be effective against them.
The ability to create a wide range of organisms, which may also be used as biological weapons, through genetic engineering is possible now. As a result, modern eugenics has become an imminent danger and should be constantly monitored and regulated.
Future research
As genetic screening becomes increasingly advanced and personal genomes become more commonplace, ongoing research aims to produce improved diagnostic methods, thereby providing better ways to prevent genetic disorders and other genetic conditions.
With the rapid development in genetic modification techniques and modern eugenics, designer babies may not be science fiction forever, thus creating an ethical dilemma on the horizon. Designer babies are children whose genetic characteristics, and consequently their physical characteristics and susceptibility to hereditary diseases, are selected by their parents. The same procedure could be used to enhance other features such as color of hair or skin, body build, and even intelligence.
Genetic engineering of humans to better survive space travel may also be an ethical concern. For instance, the advancement in gene technology may make humans better suited to endure weightlessness and cosmic irradiation (radiation from space) during interstellar transit (travel between the stars). Genetic engineering refers to the deliberate manipulation of the genetic makeup of an organism or population of organisms to achieve a planned and desired result.
Author information
This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
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