Category Archives: Genetic Engineering

Melissa Nolan

By the end of this chapter, students should be able to:

Those beautiful blue eyes you inherited from your mother are actually a result of a complex science known as Genetics. The scientific field of genetics studies genes in our DNA. Genes are units of heredity transferred from a parent to offspring and determine some characteristic of offspring. Your genes are responsible for coding all of your traits- including hair color, eye color, and so on. In recent years, scientists began exploring the concept of gene editing, which is the deliberate manipulation of genetic material to achieve desired results. Gene editing can potentially alter any given trait in an organism- from height to hair texture to susceptibility for certain diseases.

Gene editing applied to humans is referred to as Human Genetic Engineering, or HGE. There is extensive debate in and out of the scientific community regarding the ethics of HGE. Much of this debate stems from how this technology will affect society, and vice versa. Individuals may harbor concerns about the rise of designer babies or scientists playing God by determining the traits of an individual. On the contrary, HGE presents potential cures to diseases caused by genetic mutations. Human Genetic Engineering (HGE) is a novel technology which presents various ethical concerns and potential consequences. HGE should be approached cautiously and with extensive governmental regulation given its history, its current state, and the potential it has to change the world in the future.

Genetic Encoding of Proteins by MIT OpenCourseWare is licensed under CC BY-NC-SA 2.0

HGE utilizes CRISPR/Cas9 gene editing tools to cut out specific genes and replace them with a newly designed gene.

HGE encompasses a variety of methods which all work to produce a deliberate change in the human genome. The most common and prevalent way to edit the human genome is via CRISPR/Cas9. CRISPR stands for clustered regularly interspaced short palindromic repeats, and Cas9 is a protein that functions as scissors to cut DNA/genes. The CRISPR/Cas9 system originally developed as a part of a bacterias immune system, which can recognize repeats in DNA of invading viruses, then cut them out. Since then, scientists have harnessed the CRISPR/Cas9 system to cut DNA sequences of their choice and then insert new DNA sequences in their place.

The CRISPR/Cas9 system allows for designer genomes, and rapid engineering of any cells programming. With the use of CRISPR/Cas9, scientists can cut out certain traits from an individuals cells and insert new traits into those same cells.

CRISPR Cas9 System by Marius Walter is licensed under CC-BY-SA-4.0

Gene therapy is a recently-developed technology which can be applied to both somatic and germline genome editing.

Gene therapy concepts were initially introduced in the 1960s, utilizing outdated methods, such as recombinant DNA technology and viral vectors, to edit microorganisms genomes. Recombinant DNA consists of genetic material from multiple sources. The first experiments involved transferring a genome from one bacteria to another via a viral vector. Soon after was the first successful transformation of human cells with foreign DNA. The success of the experiment prompted public concern over the ethics of gene therapy, and led to political regulation. In the gene therapy report of the Presidents Commission in the United States, germline genome editing was deemed problematic over somatic genome editing. Also, non-medical genome editing was deemed problematic over medical genome editing. Germline genome editing occurs when scientists alter the genome of an embryo, so that the entire organism has altered genes and the traits can be passed to offspring. Somatic genome editing involves editing only a few cells in the entire organism so that traits can not be passed down to offspring. In response to the report, the rDNA Advisory Committee of the National Institutes of Health was formed and proposed the first guidelines for the gene therapy clinical trials. This is an example of technological determinism, in which technology determines the development of its social structure and cultural values or regulations.

In the past few decades, gene editing has advanced exponentially, introducing state-of-the-art technologies such as the CRISPR/Cas9 system, which was developed to induce gene modifications at very specific target sites. Thus, gene editing became a major focus for medical research (Tamura, 2020). Gene editing has led to the potential for development of treatment strategies for a variety of diseases and cancers. So far, somatic genome editing has shown promise in treating leukemia, melanoma, and a variety of other diseases. In this way, HGE may be demonstrative of cultural determinism, in which the culture we are raised presents certain issues which necessitate the development of a specific technology.

DNA CRISPR Scissors by Max Pixel is licensed under CC0 1.0

CRISPR/Cas9 is the primary technology proposed for use in HGE. HGE presents a variety of pros and cons to society.

Somatic genome editing in HGE via the CRISPR/Cas9 system has proven to be effective at editing specific genome sites. Since 2015, genome editing technologies have been used in over 30 human clinical trials and have shown positive patient outcomes. The treatment of disease may be a positive benefit of HGE, but there are also various potential risks. Various forms of deliberative democracies formed in recent years to address scientific and ethical concerns in HGE. Deliberative democracies afrm the need to justify technological decisions made by citizens and their representatives with experts in the field via deliberation. Overall, the consensus remains that the pros and cons of HGE are not equivalent enough to justify widespread use of the technology.

Current human clinical trials show successful transformation of human immune cells to HIV-resistant cells. This implies that HGE may be the cure for HIV(Hu, 2019). Other successful somatic genome editing trials treated myeloma, leukemia, sickle cell disease, various forms of epithelial cancers, and hemophilia. Thus, gene editing has provided novel treatment options for congenital diseases and cancers (Tamaura, 2020). Congenital diseases are those present from birth, and typically have a genetic cause. For these reasons, scientific summits concluded HGE is ethical for research regarding somatic genome editing in congenital diseases and cancers.

There are many safety concerns regarding CRISPR applications, mainly in germline genome editing. As a result of technological determinism, a leading group of CRISPR/Cas9 scientists and ethicists met for the international Summit on Human Gene Editing. The summit determined that heritable genome research trials may be permitted only following extensive research on risks and benefits of HGE. However, the summit concluded that federal funding cannot be used to support research involving human embryos with germline editing techniques. These decisions were made to avoid potential risks such as the following.

The major concerns regarding germline genome editing in HGE include: serious injury or disability, a blurry line between therapeutic applications of HGE and medical applications, misapplications, potential for eugenics ( the study of how to arrange reproduction within a human population to increase the occurrence of heritable characteristics regarded as desirable), and inequitable access to the technology.

HGE is a complex technology which presents a variety of risk factors for the coming decades. Deliberative democracy is necessary to keep this technology in check, ethically.

The future of HGE is uncertain and requires immense forethought. The American Society of Human Genetics workgroup developed a position statement on human germline engineering. The statement argues that it is inappropriate to perform germline gene editing that culminates in human pregnancy; and that in vitro(outside of an organism) germline editing should be permitted with appropriate oversight. It also states future clinical human germline editing requires ethical justification, compelling medical rationale, and evidence that supports its clinical usage. Many of these decisions were made based on the potential concerts over the future possibilities of the technology.

At the societal level, there may be concerns related to eugenics, social justice, and accessibility to technology. Eugenics could potentially reinforce prejudice and enforce exclusivity in certain physical traits. Traits can be preselected for, thus labeling some as good and others as unfavorable. This may perpetuate existing racist ideals, for example.

Moreover, germline genome editing may also increase the amount of inequality in a society. Human germline editing is likely to be very expensive and access may be limited to certain geographic regions, health systems, or socioeconomic statuses. Even if human genetic engineering is only used for medical purposes, genetic disease could become an artifact of class, location, or ethnic group. Therefore, preclinical trials are necessary to establish validity, safety, and efficacy before any wide scale studies are initiated.

Others argue that HGE may lessen genetic diversity in a human population, creating a biological monoculture that could lead to disease susceptibility and eventual extinction. Analyses have predicted that there will be negligible effect on diversity and will more likely ensure the health and longevity of humans (Russel, 2010). Legacy thinking may be responsible for the hesitations towards continuing forward with HGE, as there are also many potential pros for genetic engineering. Legacy thinking is using outdated thinking strategies and actions which may not be useful anymore.

In an alternative modernity, we can imagine HGE as an end-all for most congenital diseases and cancers. Moreover, it may be used in germline gene editing to prevent certain birth defects or heritable diseases. So, although HGE has a variety of potential risk factors, there is also great promise for novel medical therapies in the coming decades. The continued use of this technology should be approached cautiously and with extensive governmental regulation, allowing for research regarding its medical applications only.

In 2016, germline gene editing was proven feasible and effective in chickens by leading researchers in genetic engineering, Dimitrov and colleagues. In this study, scientists used CRISPR/Cas9 to target the gene for an antibody/ immunoglobulin commonly produced in chickens. Antibodies are proteins produced in immune response. In the resulting population, the chickens grew normally and healthily with modified antibodies which conferred drug resistance. This study was the first to prove that germline editing is both feasible and effective.

HGE is a rapidly expanding field of research which presents novel possibilities for the coming decades. HGE utilizes CRISPR/Cas9 gene editing tools to cut out specific genes and replace them with a newly designed gene. As important as this technology is, it is also important to recognize how new it is. Gene therapy research began in the 1960s, with somatic cell editing only commencing in the past two decades. This has presented many advantages for the potential treatment of congenital diseases, but also presents various risks. Those risks stem from germline gene editing and include eugenics and inequitable access to the technology creating large socio economic divides. In the future, more regulation should be placed on the advancement of HGE research before larger-scale studies take place.

1. What is the primary technology proposed for use in HGE?

A. Recombinant DNA technology

B. CRISPR/Cas9

C. Bacterial Transformation

D. Immunoglobulin

2. When was gene therapy concepts first introduced?

A. 1920s

B. 1940s

C. 1960s

D. 1980s

3. What is a major ethical concern regarding HGE addressed in this chapter?

A. Potential for ageism

B. Gene editing is only 50% effective

C. HGE can only be used in Caucasians

D. Potential for eugenics

Answers:

Baltimore, D. et. al.(2015). A prudent path forward for genomic engineering and germline gene modification. Science. https://doi.org/10.1126/science.aab1028

Brokowski, C., & Adli, M. (2019). CRISPR Ethics: Moral Considerations for Applications of a Powerful Tool. Journal of Molecular Biology. https://doi.org/10.1016/j.jmb.2018.05.044

Cong, L., Ran, F., & Zhang, F. (2013). Multiplex Genome Engineering Using CRISPR/Cas9 Systems. Science. https://doi.org/10.1126/science.1231143

Dimitrov, L., et. al. (2016). Germline Gene Editing in Chickens by Efficient CRISPR-Mediated Homologous Recombination in Primordial Germ Cells. Plos One. https://doi.org/10.1371/journal.pone.0154303

Hu, C. (2019). Safety of Transplantation of CRISPR CCR5 Modified CD34+ Cells in HIV-Infected Subjects with Hematological Malignancies. U.S National Library of Medicine. https://clinicaltrials.gov/ct2/show/NCT03164135

Ormond, K., et. al.(2017). Human Germline Genome Editing. AJHG. https://doi.org/10.1016/j.ajhg.2017.06.012

Russell P.(2010) The Evolutionary Biological Implications of Human Genetic Engineering, The Journal of Medicine and Philosophy: A Forum for Bioethics and Philosophy of Medicine. https://doi.org/10.1093/jmp/jhq004

Tamura, R., & Toda, M. (2020). Historic Overview of Genetic Engineering Technologies for Human Gene Therapy. Neurologia medico-chirurgica. https://doi.org/10.2176/nmc.ra.2020-0049

Thomas, C. (2020). CRISPR-Edited Allogeneic Anti-CD19 CAR-T Cell Therapy for Relapsed/Refractory B Cell Non-Hodgkin Lymphoma. ClinicalTrials. https://clinicaltrials.gov/show/NCT04637763

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18 Human Genetic Engineering - Clemson University

Genetic engineering is the process of altering the genetic composition of plants, animals, and humans. The most practical application of genetic engineering is to create a more sustainable food system for the people of Earth, but there are other ways we can use it to our advantage as well.

Unfortunately, there are both pros and cons of genetic engineering. For every benefit, there is a list of concerns and potential problems we need to consider. There is a substantive argument on both sides of genetic engineering, and well explore both ahead.

Most people tend to focus on the negatives of genetic engineering, but there are some substantial positive we need to consider as well. Genetic engineering is a debate, and there are some good points on each side. You have to look at both the pros and cons of genetic engineering if you want to make an informed decision on the matter.

Evolution takes thousands of years to adapt to our surroundings, but genetic engineering offers a quicker path forward. With the assistance of genetic engineering, we could force our bodies to adapt to the changing climate of our planet.

Additionally, we could tack-on some extra years to our lives by altering our cells, so our bodies dont deteriorate as quickly as they currently do. The fountain of youth might be within our reach, and many look forward to advancements in the area of genetic engineering.

If we choose to go down this path, well feel better as we age and be able to outlast some of the diseases that currently take us down. We still wont be able to live forever, but genetic engineering shows promise in extending the prime of our lives.

Food shortage is a massive problem in the world, especially with the growing population. Were destroying natural habitats to make way for farmland, and overgrazing is causing current pastures to become dry and uninhabited.

The answer to this problem could come in the form of genetic engineering. If we can alter the composition of vegetables and animals, we can create new foods that might have more nutritional value than nature creates on its own.

We might even be able to advance to a point where foods give us medicines we need to combat widespread viruses and illnesses. Food is one of the most promising spaces when considering the prospect of genetic engineering.

A lot of diseases depend on genetic predisposition. Some people are more likely to get cancer, Alzheimers and other diseases than their neighbor. With genetic engineering, we can get rid of these genetic predispositions once and for all.

There will likely still be some environmental concerns that will cause diseases, but if we start altering the genes of humans, we may become resistant to genetic abnormalities. Family history wont mean anything when it comes to things like cancer, and we can start eliminating diseases that are completely based on genetics.

There are already a handful of diseases and illnesses we can detect while a baby is still in the womb. We even can genetically engineer some diseases and illnesses out of a babys system before theyre born.

Finding out your baby has a disease can be devastating, and some parents make the difficult choice to spare their child possible pain. If you know that your baby might suffer and die a few months after theyre born, you have to decide whether or not you want to roll the dice.

In the future, we might be able to eliminate the chances of unhealthy babies. Diseases like Huntingtons offer a substantial chance that the carrier will pass it onto their child. If the child isnt positive for the disease, theyll still be a carrier and have to deal with the same dilemma when it comes time to have kids of their own.

Genetic engineering has the potential to stop these threats in their tracks. Parents wont have to worry about birthing a healthy son or daughter. Science will guarantee that every baby is happy and healthy when they come into this world.

Of course, genetic engineering isnt entirely positive. There is an upside to the ability to genetically alter humans and animals, but only in ideal situations.

Our world isnt perfect, and scientists make mistakes all the time. We cant assume that genetic engineering will be available to the entirety of the human population, which is a flaw in itself.

The negatives of genetic engineering seem to outweigh the positives, especially since there is so much room for error. We dont know what were tampering with, which opens the door to a host of potential problems.

There are a couple of ethical problems with genetic engineering that we need to consider as a society. Those who subscribe to religion will see genetic engineering as blasphemy, for instance. Wed be playing God, in a sense. Anyone who believes in creation will be expressly against genetic engineering especially in human children.

Those who are on the opposite side of the spectrum from religious people probably wont love genetic engineering either. Genetically engineered food might work, but changing the genes of people will add to the overpopulation problem were currently experiencing.

Diseases are one of the most effective forms of population control. We dont have the heart to eliminate other humans in the name of population control, so disease does it for us. If we eliminate diseases, humans will have virtually no threat left on this planet.

Living longer lives might be ideal, but it isnt practical. If we extend the prime of our lives, were opening the door to having more children. Since all children would be in perfect health, well see a population increase that could have devastating consequences.

If genetic engineering becomes a reality, it will likely only be available to the richest members of society. Theyll be able to extend their lives, limit diseases, and make sure their children are always healthy when theyre born

When this happens, natural selection is completely obsolete. Instead, the wealthiest in society will thrive while the poor will die-out. Eventually, genetic diversity will completely disappear as genetically engineered children all express the most desirable characteristics

This problem also arises in nature if we decide to engineer plants and animals genetically. These organisms might start as food, but could introduce themselves to the wild and take over. Theyll decimate natural species, and eventually be the only thing left.

One of the biggest hurdles in genetic engineering is the possibility of errors or genetic defects, especially in humans. Scientists have a general understanding of what creates a functioning human, but they dont yet have all the pieces to the puzzle.

When it comes down to changing humans at a cellular level, scientists dont yet have the understanding of how small changes can affect the development of a growing baby. Changing genes could result in more damaging birth defects or even miscarriages.

Furthermore, tampering with diseases could end up creating a super-disease that is even harder to combat. There are too many variables in the human body for genetic engineering to work to the fullest potential. Even if it could, people will probably be too nervous to trust scientists tampering with the cells of their future children.

Science still isnt at a point where they can alter the genes of humans to prevent all diseases in unborn children, but it might be there soon. When that time comes, some might take genetic engineering to its logical extreme.

Our priority will be to create healthy children. Once we perfect this process, though, where to, we go? The next logical step is the ability to pick certain traits that our children will have. We might be able to select whether we have a boy or girl. Then, we can decide what eye color and hair color they have.

Pretty soon, were selecting every trait that our child has before they leave the womb. Nature will be virtually out of the question at this point, and people with enough money will design their babies from scratch.

Since the pros and cons of genetic engineering are compelling, its worth it to explore the possibility further. We still havent reached a place where scientists fully understand the opportunities genetic engineering presents, so they still have years of research on their hands.

In the end, though, no system of genetically altering humans, animals, or plants will be perfect. There is a massive potential for errors, and we likely wont have equal opportunities if and when scientists ever crack the case.

Although the positives of genetic engineering are convincing, the negatives can be terrifying. If we ever get to the point where we can genetically alter humans, we need to consider the moral, ethical, and practical application of technology before going any further.

The rest is here:
Pros and Cons of Genetic Engineering - Benefits and Risks

Introduction

Heard about genes? The biological things that are responsible for the characteristics of any living organism. Be it me, you, or an animal, or a microbe.

Genes define the characteristics of the organism, they are made up of DNA and most of the genes act as an instruction manual to make protein. Generally, these genes come from the parents. Each organism has two sets of genes, one from each parent.

The majority of genes are identical in all humans, but a small number of genes (less than 1% of the total) vary slightly. Alleles are variants of the same gene with minor variations in DNA base sequence. These minor variations contribute to the individuality of each person's physical features.

Genes are given special names by scientists to keep track of them. Sometimes, these names are too long, so scientists keep track of them with symbols or numbers.

Now that we know what genes are. Let me ask you a simple question. Are genes only naturally occurring and can one gain them from their parents only?

No, they can be changed or manufactured using other genes. New genes can be formed in the laboratory. The best answer to the above question lies in the concept of genetic engineering. So, let us dive into the topic and explore what genetic engineering is.

The use of recombinant DNA (rDNA) technology to insert desired characters into species is known as genetic engineering. A genetically engineered (GE) animal is one that has a new trait, thanks to the recombinant DNA (rDNA) definition.

Although traditional breeding methods have long been used to improve animal traits, genetic engineering is a much more effective method of incorporating desirable traits into animals.

Still, lets understand the significance of recombinant DNA (rDNA) in genetic engineering;

Recombinant DNA is nothing but a technology that uses enzymes to cut and paste desirable parts of DNA sequences. In this way, a new gene is formed by the use of rDNA which contains the characteristics which we desired to insert into an animal. This newly formed rDNA is then ferried to the suitable host cell where it can be copied in order to get the desired result.

Human DNA, for example, can be engineered in such a way that it can be repeated or replicated in bacteria or yeast.

Attaching suitable elements to a piece of DNA and then moving it into a bacterial or yeast cell, with those elements instructing the bacterial or yeast cell to copy this DNA alongside its DNA, is what this method entails. DNA cloning is the term for this procedure and the resulting DNA is called Recombinant DNA or rDNA.

(Must read: Nanotechnology Applications in Biology)

Genetic engineering techniques have the following types-

Here rDNA is used to create a new gene and then gene transfer is carried out by inserting the gene into plasmid liquid and then transferring it into the host cell.

Gene delivery is the technique of inserting the desired gene in the host genome to get the characteristics we wanted to insert. Some methods used in it are Electroporation, solicitation and viral vector-mediated gene transfer, and liposome-mediated gene transfer

The modern method using electric current to carry out genetic engineering. In this, pores are created in cells using the current to enable the transfer of nucleic acid in a cell. This process is also referred to as electrotransfer.

A gene-editing technique is used to edit the genome, allowing for the removal of unwanted DNA sequences or the insertion of a new gene into the host genome. Some well-known gene-editing techniques used in gene therapy experiments include CRISPR-CAS9, TALEN, and ZFN.

Now you must be curious that even though these techniques are used, what is the process of genetic engineering?

(Also read: AI applications in Chemistry)

The majority of recombinant DNA technology entails inserting foreign genes into the plasmids of typical laboratory bacteria strains. Plasmids are the tiny DNA rings that are not part of a bacterium's chromosome (chromosome is the organism's major reservoir of genetic information).

Despite this, they are capable of guiding protein synthesis and, like chromosomal DNA, they are replicated and passed on to the bacteriums progeny.

Researchers are then able to generate an essentially infinite number of copies of the inserted gene by introducing foreign DNA (for example, a mammalian gene) into a bacterium.

Furthermore, if the inserted gene is functional (that is if it drives protein synthesis), the transformed bacteria will create the protein that the foreign DNA specifies.

In the end of all the creation, scientists figure out and choose the best technique for insertion or placing of the engineered gene in the desired genome taking the process to completion.

Many theoretical and practical aspects of gene function and organization have been substantially improved thanks to genetic engineering.

In medicine, genetic engineering has been used to mass-produce human insulin, human growth hormones, alpha-interferon, a hepatitis B vaccine.

Follistim (a fertility treatment), human albumin, monoclonal antibodies, antihemophilic factors, vaccinations, and a variety of other medications have been discovered with the help of genetic engineering.

Many other therapeutically important compounds have also been developed using recombinant DNA technology.

Still, the most important of them remains the manufacturing of genetically engineered crops. For example, let us suppose, there is a crop that grows in hilly areas and isnt prone to rains. But after a few years in that area, it rains like the daily sunlight.

In that case, the farmers there will need a crop that will grow like the same crop but will be resistant to water. So, some genetic engineering will be required here to insert the desired characteristic in the specific crop.

This genetic engineering technique has helped a lot in the creation of hybrid plants and has saved the souls of many farmers.

Some of the other rDNA traits used in crop development are-

Also, genetically engineered food is a prime application of it. (Source)

An example of genetic engineering as used by some researchers is in the making of a goat that produces spider silk.

As we know, the stretchable spider web is one of the strongest fibers found around us. It has high tensile strength and is even stronger than steel.

Theoretically, it might have changed use from the making of fake tendons to the ropes for parachutes. On the off chance that alone we had the option to create it in adequate amounts.

Nexia Biotechnologies Company said it has an answer: " goat milk contains proteins of cobweb! The scientists embedded the quality from arachnid DNA quality into goats' DNA so that it secretes in their milk the protein for building the net.

This milk can be utilized to create Biosteel material with attributes like cobwebs. The webs formed from this process, i.e. the process of genetic engineering are called recombinant webs resembling the rDNA used in their creation.

In the field of genetic engineering, bacteria were the very first creatures to be genetically modified in 1973, followed by mice in 1974. Since then, scientists and researchers have come a long way and they mostly owe it to technology rapidly evolving each day.

(Also read: What is Clean Energy?)

Gene is one of the most crucial components of a living organism and genetic engineering is like a blessing to natural scientists.

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What is Genetic Engineering? Types, Process & Applications

How artificial skin is made and its uses, from treating burns to skin cancer  South China Morning Post

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How artificial skin is made and its uses, from treating burns to skin cancer - South China Morning Post

Fernando PardoManuel-de-VillenaChairProfessorUNC Department of Genetics

The mission of the department is to provide basic and applied genetic/genomic research, education and training at the interface between biology, chemistry, physics, computer science, mathematics, the social sciences, public health and medicine in order to have a profound effect on how medicine will be practiced in the future.

Our graduate programs train students to be creative, sophisticated research scientists prepared to pursue careers focused in genetics and genomics working in academic science, government, or commercial positions. Students conduct their dissertation research using diverse experimental approaches from classical genetics to the most modern molecular methods to address a broad range of contemporary problems in biomedical science.

The Department also includes a clinical arm focused on medical genetics, which covers the broad spectrum of clinical genetic research from disease prevention to diagnosis and treatment. This specialty includes evaluation, mutation discovery, counseling and risk assessment through analysis and genetic testing. Locating the clinical group alongside basic scientists facilitates integration of cutting edge genetic research with patient care.

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Welcome to the UNC Department of Genetics | Department of Genetics

Global Genetically Modified Crops Market Is Projected To Grow At A 6% Rate Through The Forecast Period  EIN News

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Global Genetically Modified Crops Market Is Projected To Grow At A 6% Rate Through The Forecast Period - EIN News

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Genetic engineering is often used in combination with traditional breeding to produce the genetically engineered plant varieties on the market today.

For thousands of years, humans have been using traditional modification methods like selective breeding and cross-breeding to breed plants and animals with more desirable traits. For example, early farmers developed cross-breeding methods to grow corn with a range of colors, sizes, and uses. Todays strawberries are a cross between a strawberry species native to North America and a strawberry species native to South America.

Most of the foods we eat today were created through traditional breeding methods. But changing plants and animals through traditional breeding can take a long time, and it is difficult to make very specific changes. After scientists developed genetic engineering in the 1970s, they were able to make similar changes in a more specific way and in a shorter amount of time.

A Timeline of Genetic Modification in Modern Agriculture

PDF: 152KB

Circa 8000 BCE: Humans use traditional modification methods like selective breeding and cross-breeding to breed plants and animals with more desirable traits.

1866: Gregor Mendel, an Austrian monk, breeds two different types of peas and identifies the basic process of genetics.

1922: The first hybrid corn is produced and sold commercially.

1940: Plant breeders learn to use radiation or chemicals to randomly change an organisms DNA.

1953: Building on the discoveries of chemist Rosalind Franklin, scientists James Watson and Francis Crick identify the structure of DNA.

1973: Biochemists Herbert Boyer and Stanley Cohen develop genetic engineering by inserting DNA from one bacteria into another.

1982: FDA approves the first consumer GMO product developed through genetic engineering: human insulin to treat diabetes.

1986: The federal government establishes the Coordinated Framework for the Regulation of Biotechnology. This policy describes how the U.S. Food and Drug Administration (FDA), U.S. Environmental Protection Agency (EPA), and U.S. Department of Agriculture (USDA) work together to regulate the safety of GMOs.

1992: FDA policy states that foods from GMO plants must meet the same requirements, including the same safety standards, as foods derived from traditionally bred plants.

1994: The first GMO produce created through genetic engineeringa GMO tomatobecomes available for sale after studies evaluated by federal agencies proved it to be as safe as traditionally bred tomatoes.

1990s: The first wave of GMO produce created through genetic engineering becomes available to consumers: summer squash, soybeans, cotton, corn, papayas, tomatoes, potatoes, and canola. Not all are still available for sale.

2003: The World Health Organization (WHO) and the Food and Agriculture Organization (FAO) of the United Nations develop international guidelines and standards to determine the safety of GMO foods.

2005: GMO alfalfa and sugar beets are available for sale in the United States.

2015: FDA approves an application for the first genetic modification in an animal for use as food, a genetically engineered salmon.

2016: Congress passes a law requiring labeling for some foods produced through genetic engineering and uses the term bioengineered, which will start to appear on some foods.

2017: GMO apples are available for sale in the U.S.

2019: FDA completes consultation on first food from a genome edited plant.

2020: GMO pink pineapple is available to U.S. consumers.

2020: Application for GalSafe pig was approved.

GMO (genetically modified organism) has become the common term consumers and popular media use to describe foods that have been created through genetic engineering. Genetic engineering is a process that involves:

How Are GMOs Made? Fact Sheet

The following example gives a general idea of the steps it takes to create a GMO plant. This example uses a type of insect-resistant corn called Bt corn. Keep in mind that the processes for creating a GMO plant, animal, or microorganism may be different.

To produce a GMO plant, scientists first identify what trait they want that plant to have, such as resistance to drought, herbicides, or insects. Then, they find an organism (plant, animal, or microorganism) that already has that trait within its genes. In this example, scientists wanted to create insect-resistant corn to reduce the need to spray pesticides. They identified a gene in a soil bacterium called Bacillus thuringiensis (Bt), which produces a natural insecticide that has been in use for many years in traditional and organic agriculture.

After scientists find the gene with the desired trait, they copy that gene.

For Bt corn, they copied the gene in Bt that would provide the insect-resistance trait.

Next, scientists use tools to insert the gene into the DNA of the plant. By inserting the Bt gene into the DNA of the corn plant, scientists gave it the insect resistance trait.

This new trait does not change the other existing traits.

In the laboratory, scientists grow the new corn plant to ensure it has adopted the desired trait (insect resistance). If successful, scientists first grow and monitor the new corn plant (now called Bt corn because it contains a gene from Bacillus thuringiensis) in greenhouses and then in small field tests before moving it into larger field tests. GMO plants go through in-depth review and tests before they are ready to be sold to farmers.

The entire process of bringing a GMO plant to the marketplace takes several years.

Learn more about the process for creating genetically engineered microbes and genetically engineered animals.

Scientists are developing new ways to create new varieties of crops and animals using a process called genome editing. These techniques can make changes more quickly and precisely than traditional breeding methods.

There are several genome editing tools, such as CRISPR. Scientists can use these newer genome editing tools to make crops more nutritious, drought tolerant, and resistant to insect pests and diseases.

How GMOs Are Regulated in the United States

GMO Crops, Animal Food, and Beyond

How GMO Crops Impact Our World

See more here:
Science and History of GMOs and Other Food Modification Processes

Top Questions

What is genetics?

Genetics is the study ofheredityin general and ofgenesin particular. Genetics forms one of the central pillars ofbiologyand overlaps with many other areas, such as agriculture,medicine, andbiotechnology.

Is intelligence genetic?

Intelligenceis a very complex human trait, the genetics of which has been a subject of controversy for some time. Even roughly measured via diverse cognitive tests, intelligence shows a strong contribution from the environment.

How is genetic testing done?

Genetic testing typically is issued only after a medical history, a physical examination, and the construction of a family pedigree documenting familialgenetic diseaseshave been considered. The genetic tests themselves are carried out using chemical, radiological, histopathologic, and electrodiagnostic procedures. Genetic testing may involve cytogenetic analyses to investigate chromosomes, molecular assays to investigate genes and DNA, or biochemical assays to investigateenzymes,hormones, oramino acids.

Summary

genetics, study of heredity in general and of genes in particular. Genetics forms one of the central pillars of biology and overlaps with many other areas, such as agriculture, medicine, and biotechnology.

Since the dawn of civilization, humankind has recognized the influence of heredity and applied its principles to the improvement of cultivated crops and domestic animals. A Babylonian tablet more than 6,000 years old, for example, shows pedigrees of horses and indicates possible inherited characteristics. Other old carvings show cross-pollination of date palm trees. Most of the mechanisms of heredity, however, remained a mystery until the 19th century, when genetics as a systematic science began.

Genetics arose out of the identification of genes, the fundamental units responsible for heredity. Genetics may be defined as the study of genes at all levels, including the ways in which they act in the cell and the ways in which they are transmitted from parents to offspring. Modern genetics focuses on the chemical substance that genes are made of, called deoxyribonucleic acid, or DNA, and the ways in which it affects the chemical reactions that constitute the living processes within the cell. Gene action depends on interaction with the environment. Green plants, for example, have genes containing the information necessary to synthesize the photosynthetic pigment chlorophyll that gives them their green colour. Chlorophyll is synthesized in an environment containing light because the gene for chlorophyll is expressed only when it interacts with light. If a plant is placed in a dark environment, chlorophyll synthesis stops because the gene is no longer expressed.

Genetics as a scientific discipline stemmed from the work of Gregor Mendel in the middle of the 19th century. Mendel suspected that traits were inherited as discrete units, and, although he knew nothing of the physical or chemical nature of genes at the time, his units became the basis for the development of the present understanding of heredity. All present research in genetics can be traced back to Mendels discovery of the laws governing the inheritance of traits. The word genetics was introduced in 1905 by English biologist William Bateson, who was one of the discoverers of Mendels work and who became a champion of Mendels principles of inheritance.

Although scientific evidence for patterns of genetic inheritance did not appear until Mendels work, history shows that humankind must have been interested in heredity long before the dawn of civilization. Curiosity must first have been based on human family resemblances, such as similarity in body structure, voice, gait, and gestures. Such notions were instrumental in the establishment of family and royal dynasties. Early nomadic tribes were interested in the qualities of the animals that they herded and domesticated and, undoubtedly, bred selectively. The first human settlements that practiced farming appear to have selected crop plants with favourable qualities. Ancient tomb paintings show racehorse breeding pedigrees containing clear depictions of the inheritance of several distinct physical traits in the horses. Despite this interest, the first recorded speculations on heredity did not exist until the time of the ancient Greeks; some aspects of their ideas are still considered relevant today.

Hippocrates (c. 460c. 375 bce), known as the father of medicine, believed in the inheritance of acquired characteristics, and, to account for this, he devised the hypothesis known as pangenesis. He postulated that all organs of the body of a parent gave off invisible seeds, which were like miniaturized building components and were transmitted during sexual intercourse, reassembling themselves in the mothers womb to form a baby.

Aristotle (384322 bce) emphasized the importance of blood in heredity. He thought that the blood supplied generative material for building all parts of the adult body, and he reasoned that blood was the basis for passing on this generative power to the next generation. In fact, he believed that the males semen was purified blood and that a womans menstrual blood was her equivalent of semen. These male and female contributions united in the womb to produce a baby. The blood contained some type of hereditary essences, but he believed that the baby would develop under the influence of these essences, rather than being built from the essences themselves.

Aristotles ideas about the role of blood in procreation were probably the origin of the still prevalent notion that somehow the blood is involved in heredity. Today people still speak of certain traits as being in the blood and of blood lines and blood ties. The Greek model of inheritance, in which a teeming multitude of substances was invoked, differed from that of the Mendelian model. Mendels idea was that distinct differences between individuals are determined by differences in single yet powerful hereditary factors. These single hereditary factors were identified as genes. Copies of genes are transmitted through sperm and egg and guide the development of the offspring. Genes are also responsible for reproducing the distinct features of both parents that are visible in their children.

In the two millennia between the lives of Aristotle and Mendel, few new ideas were recorded on the nature of heredity. In the 17th and 18th centuries the idea of preformation was introduced. Scientists using the newly developed microscopes imagined that they could see miniature replicas of human beings inside sperm heads. French biologist Jean-Baptiste Lamarck invoked the idea of the inheritance of acquired characters, not as an explanation for heredity but as a model for evolution. He lived at a time when the fixity of species was taken for granted, yet he maintained that this fixity was only found in a constant environment. He enunciated the law of use and disuse, which states that when certain organs become specially developed as a result of some environmental need, then that state of development is hereditary and can be passed on to progeny. He believed that in this way, over many generations, giraffes could arise from deerlike animals that had to keep stretching their necks to reach high leaves on trees.

British naturalist Alfred Russel Wallace originally postulated the theory of evolution by natural selection. However, Charles Darwins observations during his circumnavigation of the globe aboard the HMS Beagle (183136) provided evidence for natural selection and his suggestion that humans and animals shared a common ancestry. Many scientists at the time believed in a hereditary mechanism that was a version of the ancient Greek idea of pangenesis, and Darwins ideas did not appear to fit with the theory of heredity that sprang from the experiments of Mendel.

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Genetics | History, Biology, Timeline, & Facts | Britannica

human genetics, study of the inheritance of characteristics by children from parents. Inheritance in humans does not differ in any fundamental way from that in other organisms.

The study of human heredity occupies a central position in genetics. Much of this interest stems from a basic desire to know who humans are and why they are as they are. At a more practical level, an understanding of human heredity is of critical importance in the prediction, diagnosis, and treatment of diseases that have a genetic component. The quest to determine the genetic basis of human health has given rise to the field of medical genetics. In general, medicine has given focus and purpose to human genetics, so the terms medical genetics and human genetics are often considered synonymous.

A new era in cytogenetics, the field of investigation concerned with studies of the chromosomes, began in 1956 with the discovery by Jo Hin Tjio and Albert Levan that human somatic cells contain 23 pairs of chromosomes. Since that time the field has advanced with amazing rapidity and has demonstrated that human chromosome aberrations rank as major causes of fetal death and of tragic human diseases, many of which are accompanied by intellectual disability. Since the chromosomes can be delineated only during mitosis, it is necessary to examine material in which there are many dividing cells. This can usually be accomplished by culturing cells from the blood or skin, since only the bone marrow cells (not readily sampled except during serious bone marrow disease such as leukemia) have sufficient mitoses in the absence of artificial culture. After growth, the cells are fixed on slides and then stained with a variety of DNA-specific stains that permit the delineation and identification of the chromosomes. The Denver system of chromosome classification, established in 1959, identified the chromosomes by their length and the position of the centromeres. Since then the method has been improved by the use of special staining techniques that impart unique light and dark bands to each chromosome. These bands permit the identification of chromosomal regions that are duplicated, missing, or transposed to other chromosomes.

Micrographs showing the karyotypes (i.e., the physical appearance of the chromosome) of a male and a female have been produced. In a typical micrograph the 46 human chromosomes (the diploid number) are arranged in homologous pairs, each consisting of one maternally derived and one paternally derived member. The chromosomes are all numbered except for the X and the Y chromosomes, which are the sex chromosomes. In humans, as in all mammals, the normal female has two X chromosomes and the normal male has one X chromosome and one Y chromosome. The female is thus the homogametic sex, as all her gametes normally have one X chromosome. The male is heterogametic, as he produces two types of gametesone type containing an X chromosome and the other containing a Y chromosome. There is good evidence that the Y chromosome in humans, unlike that in Drosophila, is necessary (but not sufficient) for maleness.

A human individual arises through the union of two cells, an egg from the mother and a sperm from the father. Human egg cells are barely visible to the naked eye. They are shed, usually one at a time, from the ovary into the oviducts (fallopian tubes), through which they pass into the uterus. Fertilization, the penetration of an egg by a sperm, occurs in the oviducts. This is the main event of sexual reproduction and determines the genetic constitution of the new individual.

Human sex determination is a genetic process that depends basically on the presence of the Y chromosome in the fertilized egg. This chromosome stimulates a change in the undifferentiated gonad into that of the male (a testicle). The gonadal action of the Y chromosome is mediated by a gene located near the centromere; this gene codes for the production of a cell surface molecule called the H-Y antigen. Further development of the anatomic structures, both internal and external, that are associated with maleness is controlled by hormones produced by the testicle. The sex of an individual can be thought of in three different contexts: chromosomal sex, gonadal sex, and anatomic sex. Discrepancies between these, especially the latter two, result in the development of individuals with ambiguous sex, often called hermaphrodites. Homosexuality is unrelated to the above sex-determining factors. It is of interest that in the absence of a male gonad (testicle) the internal and external sex anatomy is always female, even in the absence of a female ovary. A female without ovaries will, of course, be infertile and will not experience any of the female developmental changes normally associated with puberty. Such a female will often have Turner syndrome.

If X-containing and Y-containing sperm are produced in equal numbers, then according to simple chance one would expect the sex ratio at conception (fertilization) to be half boys and half girls, or 1 : 1. Direct observation of sex ratios among newly fertilized human eggs is not yet feasible, and sex-ratio data are usually collected at the time of birth. In almost all human populations of newborns, there is a slight excess of males; about 106 boys are born for every100 girls. Throughout life, however, there is a slightly greater mortality of males; this slowly alters the sex ratio until, beyond the age of about 50 years, there is an excess of females. Studies indicate that male embryos suffer a relatively greater degree of prenatal mortality, so the sex ratio at conception might be expected to favour males even more than the 106 : 100 ratio observed at birth would suggest. Firm explanations for the apparent excess of male conceptions have not been established; it is possible that Y-containing sperm survive better within the female reproductive tract, or they may be a little more successful in reaching the egg in order to fertilize it. In any case, the sex differences are small, the statistical expectation for a boy (or girl) at any single birth still being close to one out of two.

During gestationthe period of nine months between fertilization and the birth of the infanta remarkable series of developmental changes occur. Through the process of mitosis, the total number of cells changes from 1 (the fertilized egg) to about 2 1011. In addition, these cells differentiate into hundreds of different types with specific functions (liver cells, nerve cells, muscle cells, etc.). A multitude of regulatory processes, both genetically and environmentally controlled, accomplish this differentiation. Elucidation of the exquisite timing of these processes remains one of the great challenges of human biology.

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Human genetics | Description, Chromosomes, & Inheritance

Overview

Genetic testing involves examining your DNA, the chemical database that carries instructions for your body's functions. Genetic testing can reveal changes (mutations) in your genes that may cause illness or disease.

Although genetic testing can provide important information for diagnosing, treating and preventing illness, there are limitations. For example, if you're a healthy person, a positive result from genetic testing doesn't always mean you will develop a disease. On the other hand, in some situations, a negative result doesn't guarantee that you won't have a certain disorder.

Talking to your doctor, a medical geneticist or a genetic counselor about what you will do with the results is an important step in the process of genetic testing.

When genetic testing doesn't lead to a diagnosis but a genetic cause is still suspected, some facilities offer genome sequencing a process for analyzing a sample of DNA taken from your blood.

Everyone has a unique genome, made up of the DNA in all of a person's genes. This complex testing can help identify genetic variants that may relate to your health. This testing is usually limited to just looking at the protein-encoding parts of DNA called the exome.

Genetic testing plays a vital role in determining the risk of developing certain diseases as well as screening and sometimes medical treatment. Different types of genetic testing are done for different reasons:

Generally genetic tests have little physical risk. Blood and cheek swab tests have almost no risk. However, prenatal testing such as amniocentesis or chorionic villus sampling has a small risk of pregnancy loss (miscarriage).

Genetic testing can have emotional, social and financial risks as well. Discuss all risks and benefits of genetic testing with your doctor, a medical geneticist or a genetic counselor before you have a genetic test.

Before you have genetic testing, gather as much information as you can about your family's medical history. Then, talk with your doctor or a genetic counselor about your personal and family medical history to better understand your risk. Ask questions and discuss any concerns about genetic testing at that meeting. Also, talk about your options, depending on the test results.

If you're being tested for a genetic disorder that runs in families, you may want to consider discussing your decision to have genetic testing with your family. Having these conversations before testing can give you a sense of how your family might respond to your test results and how it may affect them.

Not all health insurance policies pay for genetic testing. So, before you have a genetic test, check with your insurance provider to see what will be covered.

In the United States, the federal Genetic Information Nondiscrimination Act of 2008 (GINA) helps prevent health insurers or employers from discriminating against you based on test results. Under GINA, employment discrimination based on genetic risk also is illegal. However, this act does not cover life, long-term care or disability insurance. Most states offer additional protection.

Depending on the type of test, a sample of your blood, skin, amniotic fluid or other tissue will be collected and sent to a lab for analysis.

The amount of time it takes for you to receive your genetic test results depends on the type of test and your health care facility. Talk to your doctor, medical geneticist or genetic counselor before the test about when you can expect the results and have a discussion about them.

If the genetic test result is positive, that means the genetic change that was being tested for was detected. The steps you take after you receive a positive result will depend on the reason you had genetic testing.

If the purpose is to:

Talk to your doctor about what a positive result means for you. In some cases, you can make lifestyle changes that may reduce your risk of developing a disease, even if you have a gene that makes you more susceptible to a disorder. Results may also help you make choices related to treatment, family planning, careers and insurance coverage.

In addition, you may choose to participate in research or registries related to your genetic disorder or condition. These options may help you stay updated with new developments in prevention or treatment.

A negative result means a mutated gene was not detected by the test, which can be reassuring, but it's not a 100 percent guarantee that you don't have the disorder. The accuracy of genetic tests to detect mutated genes varies, depending on the condition being tested for and whether or not the gene mutation was previously identified in a family member.

Even if you don't have the mutated gene, that doesn't necessarily mean you'll never get the disease. For example, the majority of people who develop breast cancer don't have a breast cancer gene (BRCA1 or BRCA2). Also, genetic testing may not be able to detect all genetic defects.

In some cases, a genetic test may not provide helpful information about the gene in question. Everyone has variations in the way genes appear, and often these variations don't affect your health. But sometimes it can be difficult to distinguish between a disease-causing gene and a harmless gene variation. These changes are called variants of uncertain significance. In these situations, follow-up testing or periodic reviews of the gene over time may be necessary.

No matter what the results of your genetic testing, talk with your doctor, medical geneticist or genetic counselor about questions or concerns you may have. This will help you understand what the results mean for you and your family.

Explore Mayo Clinic studies of tests and procedures to help prevent, detect, treat or manage conditions.

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Genetic testing - Mayo Clinic