Pharming (Genetics)
Pharming is a biotechnological process that involves inserting genes from foreign species into plants, animals, and bacteria to create genetically modified organisms (GMOs) with medicinal applications. This technique aims to produce pharmaceutical products that are more affordable than those manufactured through traditional methods. By using genetic engineering, pharming can generate human proteins through food sources like milk or through blood transfusions, potentially reducing drug costs, especially in developing countries where access to medications can be limited.
The term "pharming" combines "pharmaceutical" and "farming," and it is also known as plant molecular farming or biopharming. The process typically begins with the splicing of DNA, known as a transgene, into the genome of a fertilized embryo. While both plants and animals can be used for pharming, animals are often preferred for their efficiency in protein production, particularly through milk. However, some scientists favor plants due to lower risks of disease transmission.
Although the costs associated with creating transgenic animals can be significant, the return on investment can be substantial, with a single animal capable of producing pharmaceuticals worth millions over its lifetime. Despite its potential benefits, pharming faces ethical concerns regarding animal welfare and safety issues related to GMOs. Nevertheless, it is viewed as a promising avenue for making healthcare more accessible and affordable globally.
Pharming (Genetics)
Pharming is the technological process of inserting genes from foreign species into plants, animals, and bacteria for the purpose of creating genetically modified organisms (GMOs). The goal of pharming is to create products that have medicinal value and that are less expensive than drugs manufactured through more traditional methods. This form of biotechnology is primarily used to make human proteins that are passed along to people through the consumption of food products, such as milk, or through blood transfusions. As the expense of producing such substances is lower, pharming has the potential to reduce the costs of drugs, particularly in third world nations where such drugs may be prohibitively expensive for the poor.
Background
The word pharming is a combination of the words pharmaceutical and farming. Pharming is known by several other names, including plant molecular farming (PMF) and biopharming. The initial goals of this form of genetic engineering were to create plants and animals that were more disease-resistant and to produce crops that required less fertilizer. Early research focused on crops such as corn and tobacco. Since then, other crops, including safflower, duckweed, rice, alfalfa, and algae, have been successfully grown using genetic engineering.
In 1990, scientists at the Roslin Institute in Scotland were able to produce a genetically engineered sheep they named Tracy. This sheep was created using a fertilized embryo called a zygote that had been injected with human DNA. This DNA contained an enzyme called alpha antitrypsin, which has applications for treating diseases such as emphysema and cystic fibrosis. As a result of this process, Tracy was able to produce alpha antitrypsin in her milk that could be used to treat people. The Roslin Institute later cloned a sheep named Dolly with the intent of quickly producing more sheep like Tracy that could naturally produce the alpha antitrypsin enzyme. In 1997, the institute also produced a sheep with a clotting factor known as human factor IX that could be used to treat hemophiliacs who are unable to naturally produce this substance.
The first drug approved for human use in the United States and made from genetically modified livestock was a drug called ATryn. It was made from the milk of goats that had been manufactured to produce a plasma protein called antithrombin. This protein is an anticoagulant (a type of drug that prevents blood from clotting) used to treat people with a rare disease called antithrombin III deficiency. Formerly, scientists relied on blood donations to gather the proteins needed to create this type of drug; however, one genetically modified goat is capable of producing as much antithrombin as that processed from ninety thousand blood donations.
Pharming uses genetic engineering to create plants, animals, and bacteria with new DNA. This occurs by splicing DNA, which is called a transgene, from one species into another. The resulting plant, animal, or bacteria is called transgenic. This process of creating hybrid genes is done through the use of recombinant DNA techniques. Recombinant DNA is formed in the laboratory by taking a piece of desired DNA (like the one that creates certain proteins) and adding it to a single cell (such as a fertilized embryo) before it begins cell division.
In mammals, this process begins by providing a hormone to a donor animal that causes it to produce many eggs. The eggs are removed and fertilized as normal with donor sperm. Scientists then add the transgene by microinjecting the foreign DNA into the male pronucleus with a micropipette needle. The transgenic pronucleus fuses with the female egg. The transgene then links with the genome in the egg. If the DNA has been successfully added to the cell, the cell will create copies of itself that contain the new genetic structure. Scientists then test the resulting embryos to collect any containing the desired transgenic structure. About 10 to 30 percent of mouse embryos have been shown to successfully carry transgenic DNA, but the process had only a 5 percent success rate in larger mammals such as cows, pigs, and sheep. The transgenic embryos are then placed in a surrogate mother, where they develop naturally into animals containing the new transgene.
Animals have proven to be particularly successful in producing desirable proteins because they naturally use the same cellular processes required to produce proteins. However, some scientists prefer using plants for pharming because animals carry a greater risk of spreading existing pathogens that carry disease than plants do. In mammals, scientists have achieved the greatest success in producing the desired proteins through milk products rather than through eggs or urine, though these delivery methods may become viable alternatives in time.
Overview
Many scientists believe that pharming may help improve health on a global level. Pharming is typically less expensive than traditional pharmaceutical methods. While pharming can require large initial investments to cover research and manufacturing expenses, it generally becomes much less expensive over time. Plants and animals are comparatively inexpensive to maintain. They can produce the necessary proteins for pharmaceuticals faster and in greater quantities than traditional methods.
Estimates about the economics of pharming have suggested that it may cost as much as $25,000 to $500,000 dollars to successfully produce one transgenic animal; however, that single animal may produce between $200 and $300 million worth of pharmaceutical drugs during its life span. Since the establishment of this practice, scientists have been able to identify and splice transgenic DNA more quickly and with greater success, thereby potentially reducing the initial costs required of pharming. Factories containing the necessary facilities to produce pharmaceuticals may cost between $200 and $400 million to build over the course of several years, while five genetically engineered goats may require only $1.5 million and less than two years to develop.
Some critics argue that it is unethical to use animals as DNA factories. The process of creating transgenic animals often costs the lives of many animals to achieve the desired offspring. Additionally, pharming has been subject to criticism that GMOs may be unsafe to eat. Concerns about the lack of consistent testing methodologies with regard to GMOs have been raised. The potential also exists for modified plants to contaminate farmed crops that are not intended to be sold as GMOs. Despite such concerns, pharming is still regarded as a promising way to produce and sell more affordable medicines.
Bibliography
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