Knowledge Class: Genetic Engineering

Showing posts with label Genetic Engineering. Show all posts

Jun 22, 2025

The Power of Genetic Engineering: How Transgenic Organisms Are Transforming Biotechnology

Biotechnology has revolutionized how we harness nature to benefit humanity. At the heart of this innovation are transgenic organisms—living beings that carry foreign genes deliberately introduced through genetic engineering. From bacteria to plants and animals, these organisms are designed to perform specific tasks, from producing medicines to cleaning the environment.

Transgenic Bacteria: Microscopic Factories of Biotechnology

Using recombinant DNA technology, scientists create bacteria that can manufacture valuable substances inside industrial vats known as bioreactors. These engineered microbes can produce large quantities of proteins, hormones (like insulin), and vaccines when the inserted foreign gene is both replicated and expressed efficiently.

Enhancing Agriculture Through Bacterial Engineering

Genetically modified bacteria are now helping farmers protect crops. For instance, bacteria that typically encourage ice formation on leaves have been re-engineered to prevent frost damage. Others, modified to carry genes for insect-killing toxins, can protect crops like corn by naturally defending plant roots against pests.

Bioremediation: Nature’s Clean-Up Crew

Some bacteria are designed to clean up environmental hazards. Scientists have enhanced the natural oil-degrading capabilities of certain bacteria to make them more effective at clearing oil spills. Others serve as biofilters to trap airborne pollutants or are used to remove sulfur from coal. Special safety features, like "suicide genes," ensure these bacteria self-destruct after completing their tasks, reducing environmental risks.

Using Bacteria to Manufacture Chemicals

Modern biotechnology allows scientists to manipulate the genes responsible for producing industrial chemicals. One successful example involves bacteria engineered to produce phenylalanine, a key ingredient in NutraSweet. These modified bacteria now serve as cost-effective, reliable producers of such compounds.

Mining and Metal Extraction with Microbes

Major mining companies already use bacteria to extract metals like copper, gold, and uranium from low-grade ores. Genetic engineering is enhancing these processes, improving both efficiency and environmental sustainability. Research is also underway to use genetically modified organisms in the paper industry for more effective bleaching.

Transgenic Plants: From Lab to Farm

Because not all plant cells accept bacterial plasmids naturally, scientists developed techniques to introduce foreign DNA into protoplasts—plant cells with the wall removed. Using electric currents, they create small openings in the plasma membrane to allow DNA entry. These modified cells can regenerate into fully functional plants.

More than 50 genetically engineered plant varieties have undergone field trials. Commonly modified crops include corn, soybeans, rice, cotton, alfalfa, and potatoes, with traits like resistance to insects, viruses, and herbicides. Some plants have even been engineered to produce human hormones and therapeutic proteins in their seeds.

Innovations include crops like mouse-ear cress, which can produce biodegradable plastic, and corn that generates antibodies capable of targeting cancer cells or treating diseases like genital herpes.

Transgenic Animals: Engineering for Health and Growth

In animals, gene insertion typically involves vortex mixing, which allows DNA to enter egg cells through microscopic holes created with silicon-carbide needles. This technique has produced larger livestock such as cattle, rabbits, pigs, and fish, with enhanced growth due to the introduction of bovine growth hormone (rbGH). These genetically engineered animals are strictly contained to prevent ecological disruption.

Gene Pharming: Turning Animals Into Pharmaceutical Producers

Gene pharming is the use of transgenic animals to produce therapeutic proteins in their milk. For example, cows or goats can be engineered to express human genes so that their milk contains drugs used to treat infections or chronic diseases. In one case, a bull carrying the gene for human lactoferrin passed this trait to offspring, resulting in a sustainable source of the medication.

Interestingly, scientists have also engineered mice to produce human growth hormone in urine, making collection and extraction easier than from milk.

Cloning Transgenic Animals: A Leap in Reproductive Technology

Cloning creates exact genetic copies of animals. In 1997, a landmark achievement occurred when scientists at the Roslin Institute in Scotland successfully cloned a sheep named Dolly using a nucleus from an udder cell inserted into an egg with its nucleus removed. The egg was then implanted into a surrogate mother, resulting in a healthy, cloned lamb.

Soon after, researchers in Hawaii and Japan cloned mice and cows using nuclei from cumulus cells, demonstrating rapid advancements in reproductive cloning. However, the cloning of humans remains legally and ethically prohibited.

Key Takeaways for Curious Minds

Transgenic bacteria are widely used to produce medicines, clean up pollution, and manufacture chemicals.
Genetic engineering has led to crops with improved yields, pest resistance, and even medical capabilities.
Transgenic animals are being used to produce therapeutic proteins, improve food production, and aid scientific research.
Cloning and gene pharming are pushing the boundaries of biotechnology, showing both promise and ethical challenges.
Biotechnology continues to reshape agriculture, medicine, and industry, offering sustainable solutions for the future.

Apr 28, 2023

Patenting Genetically Engineered Microorganisms: Legal and Scientific Implications

For a long time, scientists in the petrochemical industry were aware of certain bacteria that could break down hydrocarbons in crude oil into simpler and less harmful substances. However, since no single strain of bacteria could metabolize all hydrocarbons present in crude oil, multiple strains were used during oil spills. Unfortunately, not all of these strains could survive in varying environmental conditions, and they sometimes competed with each other, leading to reduced effectiveness.

In 2013, the Supreme Court made a significant decision that prevented the patenting of human genes. The case involved a breast cancer test that relied on the detection of a faulty BRCA1 gene. The impact of this ruling could extend to other naturally occurring substances, such as proteins from animal or human sources, microorganisms sourced from soil or sea, and compounds extracted from plants.

In 1971, Ananda Chakrabarty, an Indian American microbiologist working at General Electric, discovered plasmids that could degrade crude oil. These plasmids could be transferred to the bacterium Pseudomonas to create a genetically engineered species that did not exist in nature. This newly created "oil-eating" bacterium was capable of consuming oil several times faster than the earlier four strains combined, breaking down two-thirds of the hydrocarbons present in a typical oil spill. But, the question arose whether a living organism could be patented.

The US Constitution's Article I, Section 8 granted the right to grant patents to promote the progress of science and useful arts. It granted a fixed-term monopoly to the inventor in exchange for publicly sharing knowledge of the invention. In 1873, Louis Pasteur was granted a US patent for a purified yeast cell. The Plant Patent Act of 1930 allowed plants to be patented, as they were an exception and could foster agricultural innovation. However, in 1980, Sidney Diamond, the Commissioner of the Patent and Trademark Office, challenged the patentability of the "oil-eating" Pseudomonas on the basis that, as bacteria, they were products of nature.

In Diamond v. Chakrabarty, the US Supreme Court, in a 5-4 decision, held that "the fact that micro-organisms are alive is without legal significance for the purposes of patent law" and that "anything under the sun made by man" is patentable. This landmark decision led to an avalanche of biotechnology patent applications and approvals, including the first transgenic animal, the "Harvard Mouse," in 1988, and genetically engineered crops in 1990. Only Canada prohibited patents on higher life forms, such as mice. However, in 2013, the US Supreme Court held that naturally occurring DNA sequences were ineligible for patents.

Mar 5, 2016

Revolutionizing Albumin Production: Growing Human Serum Albumin in Rice

Albumin is a vital protein found in the blood plasma of mammals, making up 50-55% of plasma proteins in humans. Synthesized in the liver, it acts as a carrier protein for various substances including hormones, bile salts, and blood clotting factors. However, its primary role is regulating blood volume by attracting water into the circulatory system, particularly in the capillaries. In medical settings, albumin is used as a plasma expander to treat shock caused by blood loss or burns, and in emergency situations to stabilize the wounded. It also plays a critical role in drug and vaccine production.

Although human serum albumin (HSA) is extracted from blood plasma, natural sources are insufficient to meet demand. Synthetic or laboratory versions of HSA have been difficult to produce, with past attempts using potato plants and tobacco leaves proving unsuccessful. Genetic engineering has provided new tools to produce HSA, with researchers successfully growing HSA in rice grains after introducing a gene for encoding HSA using bacteria (Agrobacterium) and activating it during seed production.

A green terraced rice field in Chiangmai, Thailand.

The HSA produced in rice was chemically and physically identical to human-derived HSA and biologically equivalent in rats. This breakthrough has enormous implications for HSA production, with approximately 2.8 grams of HSA produced from 1 kilogram of brown rice, making it an extremely cost-effective method with an almost unlimited supply. This development may help meet the demand for HSA in the medical field, particularly in areas affected by blood loss and shock.

Keywords: albumin, blood plasma, carrier protein, blood volume regulation, plasma expander, shock treatment, genetic engineering, rice grain, HSA production, cost-effective, medical field.

Feb 26, 2016

The Pioneering Discovery and Transformative Role of Plasmids in Molecular Biology

In 1952, Joshua Lederberg, a renowned geneticist at the University of Wisconsin-Madison, introduced the term "plasmid" to describe a unique category of DNA molecules distinct from the chromosomal DNA. Lederberg’s goal was to create a general term that could encompass a diverse array of genetic elements that had previously been referred to by various names such as parasites, symbionts, organelles, or genes. This new classification paved the way for a deeper understanding of genetic material outside the chromosomal structure and its significant role in various biological processes.

The Rise of Plasmids in Molecular Biology

The significance of plasmids took a dramatic leap forward in the 1970s when they were found to be invaluable tools in the burgeoning field of molecular biology and genetic engineering. This breakthrough was largely thanks to the combined efforts of geneticist Herbert Boyer and biologist Stanley Cohen, who made a landmark discovery in 1973. They demonstrated the potential of plasmids as vehicles for genetic transfer by successfully transferring a gene from one species (frog) to another (bacterium Escherichia coli). Their work revealed that not only could a gene be transferred, but it could also function normally within the new host, proving the concept of gene transfer across species and laying the foundation for modern genetic engineering.

Beyond their use in gene transfer, plasmids also play a critical role in the evolution of microbial resistance and in enabling microorganisms to become pathogenic. Their ability to carry genetic information that confers survival advantages makes them crucial players in microbial adaptability.

Understanding Plasmid Structure and Function

Plasmids are small, circular DNA molecules that replicate independently of the chromosomal DNA within a cell. Their structure typically consists of two main types of genes: backbone genes and accessory genes.

Backbone genes are essential for the plasmid’s replication and maintenance within the host cell.
Accessory genes, on the other hand, are not vital for the survival of the host but provide it with certain advantages. These advantages may include the ability to degrade environmental pollutants, resist the toxic effects of heavy metals or antibiotics, or even enable the host to use specific nutrients as a carbon and nitrogen source.

Moreover, plasmids are not confined to a single bacterial species; they can be transferred between different bacterial species, which facilitates the rapid spread of beneficial traits. This gene transfer mechanism is a key factor in bacterial evolution, enabling them to adapt quickly to changing environments and acquire traits such as antibiotic resistance or virulence factors.

Plasmids as Tools in Genetic Engineering

The role of plasmids in genetic engineering cannot be overstated. They are foundational in techniques such as gene cloning, gene therapy, and recombinant protein production. One of the earliest and most influential applications of plasmids was in the production of synthetic human insulin, a breakthrough achieved by Herbert Boyer in 1978. By inserting a gene for insulin into a plasmid and introducing this recombinant plasmid into bacterial cells, Boyer was able to harness the bacterial replication machinery to produce large quantities of insulin. This method revolutionized the production of proteins for medical use, leading to the mass production of human insulin for diabetic patients.

The Future of Plasmid-Based Biotechnology

The use of plasmids in biotechnology continues to evolve, with applications ranging from targeted gene therapies to the production of complex biologics and vaccines. Their ability to transfer and replicate foreign genetic material makes plasmids indispensable in the development of novel therapeutic strategies and in advancing our understanding of genetics at the molecular level.

Final Words: The Lasting Impact of Plasmids on Science and Medicine

From their initial discovery as separate genetic elements to their role in modern genetic engineering, plasmids have proven to be indispensable in the fields of molecular biology and biotechnology. Their ability to carry and transfer genetic material has not only deepened our understanding of gene function and microbial evolution but has also paved the way for innovations in medicine, such as recombinant protein production and gene therapy. As we continue to explore and harness the potential of plasmids, their impact on science and medicine will undoubtedly grow, offering new possibilities for treating diseases and advancing biotechnology.

Joshua Lederberg at work in his laboratory at the University of Wisconsin, 1958. In addition to his discovery that bacteria can exchange genes, he is also well known for his contributions to artificial intelligence and space exploration.

Jan 8, 2016

Genetic Engineering and the Power of Recombinant DNA: A Beginner-Friendly Guide

Genetic engineering is the process of inserting a gene from one organism into the DNA of another. This makes the modified cell capable of producing a new and useful protein—something it could not do before. This technique forms the foundation of modern biotechnology.

Formation of recombinant DNA

Understanding Recombinant DNA (rDNA)

Recombinant DNA, often abbreviated as rDNA, is a strand of DNA formed by combining genetic material from two or more sources. This new DNA can be inserted into a host cell, allowing the host to express a gene that wasn’t originally part of its genome.

What Are Vectors?

Vectors act as carriers for transferring genes. A common vector is a plasmid, a small circular DNA molecule found in bacteria that replicates independently of the bacterial chromosome. Viruses, such as phages, can also serve as vectors. They inject their DNA into host cells, and this DNA can be engineered to include foreign genes.

When a plasmid is combined with foreign DNA using genetic tools, it becomes recombinant DNA. Once inserted into a bacterium, this plasmid replicates as the bacterium divides—cloning the inserted gene along the way.

The Five Key Steps of Genetic Engineering

Isolate the Gene: Extract the desired gene from the donor organism.
Insert into a Vector: Introduce this gene into a plasmid or virus.
Transfer to Host Cell: Move the vector into a bacterial host.
Identify Modified Cells: Screen for host cells that accepted the foreign DNA.
Clone the Gene: Allow the modified cells to reproduce, copying the gene.

Restriction Enzymes: Nature’s Molecular Scissors

Genetic engineers rely on restriction enzymes—proteins that naturally occur in bacteria—to cut DNA at specific sequences known as recognition sites. These sites are often palindromic sequences, meaning the sequence reads the same forward and backward.

One commonly used enzyme is EcoRI, which recognizes and cuts at the sequence GAATTC. The cuts produce sticky ends—single-stranded overhangs that help link DNA from different sources.

How DNA Fragments Are Joined

Once the sticky ends of different DNA strands find their match, the enzyme DNA ligase seals them together, forming strong covalent bonds. This final product is recombinant DNA, a hybrid molecule with genes from multiple sources.

Steps showing formation of rDNA using restriction enzyme and DNA ligase

How Recombinant DNA is Cloned

To clone a gene:

Isolate the desired gene and plasmid vector.
Cut both with the same restriction enzyme to create matching sticky ends.
Mix them together so the sticky ends pair up.
Use DNA ligase to permanently join the fragments.
Insert the recombinant plasmid into bacteria via transformation.
Allow the bacteria to multiply, copying the foreign gene during cell division.

Gene Libraries and cDNA

Plasmid and Bacteriophage Libraries

Plasmid libraries: Collections of bacteria carrying different DNA fragments.
Phage libraries: Collections of viruses engineered with DNA fragments.

These libraries hold an entire organism’s genome broken into smaller segments, ready for analysis or future use.

Using cDNA Instead of Genomic DNA

Bacteria cannot process introns—non-coding regions in DNA. To solve this, scientists use reverse transcriptase to convert mature mRNA into complementary DNA (cDNA), which contains only the coding regions of a gene. This cDNA can then be cloned and expressed in bacterial cells.

Cloning a Gene in a Bacterial Plasmid

Finding a Gene with a Probe

If scientists already know part of a gene’s sequence, they can create a probe—a short piece of RNA or DNA that matches the sequence. These probes are labeled with radioactive or fluorescent tags. When added to a sample, they bind to the target gene through base pairing, allowing researchers to locate and isolate it for further study.

The Polymerase Chain Reaction (PCR)

What Is PCR?

Developed by Kary Mullis in 1983, PCR is a method that allows scientists to make millions of copies of a specific DNA segment in a test tube. This is done without needing to clone the gene in a living cell.

How PCR Works

PCR uses:

Primers: Short sequences that match the start and end of the target DNA.
Taq polymerase: A heat-resistant enzyme from hot spring bacteria.
Thermocycler: A machine that rapidly heats and cools samples to carry out DNA replication.

This method is highly specific and efficient, allowing scientists to study very small amounts of DNA.

DNA Fingerprinting and RFLPs

When DNA is treated with restriction enzymes, it breaks into fragments of different lengths. These fragments vary from person to person due to differences in DNA sequences, known as restriction fragment length polymorphisms (RFLPs).

Using gel electrophoresis, the fragments are separated by size, creating a unique pattern—similar to a barcode—that can be used for:

Criminal identification
Paternity testing
Diagnosing genetic diseases

Preparation of a genomic library

Sequencing DNA with Gel Electrophoresis

In this process, DNA fragments move through a gel under electric current. Smaller fragments move faster and farther. This allows scientists to identify and analyze the DNA based on the pattern of separated fragments. The gel is later stained to visualize the results.

Real-World Applications

Genetic engineering is not just a scientific marvel—it’s a tool with real-life impact. Its uses include:

Creating insulin and other medications
Identifying criminals and victims through DNA evidence
Tracking genetic diseases and mutations
Mapping evolutionary relationships
Developing genetically modified crops and organisms

Reverse Transcriptase helps make DNA for cloning

Key Takeaways for Curious Minds

Genetic engineering makes it possible to modify life at the molecular level.
Recombinant DNA technology is the foundation of modern biotechnology and medicine.
PCR revolutionized how we copy and study DNA—quickly, accurately, and in tiny amounts.
Restriction enzymes and DNA ligase act like scissors and glue to build new DNA.
Probes and DNA fingerprinting help solve crimes, track diseases, and study evolution.

With these technologies, we're not just studying life—we’re reshaping it for better health, safer environments, and a deeper understanding of who we are.

Identification of a cloned gene

Polymerase chain reaction (PCR)

Gel electrophoresis

Jan 1, 2016

The Rise of Genetic Engineering: How DNA Technology Is Shaping Our World

The rediscovery of Gregor Mendel’s work in 1900 sparked a revolution in our understanding of heredity. What began as the study of pea plants soon evolved into the complex field of modern genetics. By the mid-1970s, biology entered a groundbreaking phase with the emergence of recombinant DNA technology—a method that allows scientists to manipulate genetic material in unprecedented ways.

This breakthrough didn’t just expand our knowledge—it transformed how we approach biological research, medicine, agriculture, and even environmental protection.

What Is Recombinant DNA Technology?

Recombinant DNA (rDNA) technology is the process of combining DNA from different sources to create a new genetic sequence. These custom-made DNA strands can be inserted into living cells, allowing the organism to gain new traits—traits it wouldn’t naturally have.

This technique laid the foundation for genetic engineering, which involves directly altering the DNA of an organism to produce specific results.

Genetic Engineering: Redefining What’s Possible

Genetic engineering allows scientists to modify the genetic code of plants, animals, and microbes to express desired traits. This could mean creating pest-resistant crops, developing bacteria that produce life-saving drugs, or engineering animals to grow faster or resist disease.

This approach has led to a revolution in biotechnology—the use of living systems and organisms to solve real-world problems or produce useful products.

Biotechnology: From Ancient Practices to Modern Precision

While biotechnology might sound like a product of the digital age, its roots go back thousands of years. Early farmers unknowingly practiced a form of it when they selectively bred animals and plants for favorable traits—like sweeter fruits, stronger livestock, or disease resistance.

Even ancient civilizations harnessed microbes to make bread, cheese, and fermented beverages. What we do today with genetic engineering is an advanced, targeted version of this natural process—only now, we can alter life at the molecular level with pinpoint accuracy.

How Bacteria Became Microscopic Factories

Through genetic engineering, bacteria have been turned into efficient producers of substances that benefit humans in countless ways. For example:

Medicines: Engineered bacteria now produce insulin, growth hormones, and clotting factors used to treat diabetes, dwarfism, and hemophilia.
Vaccines: Microbes can be modified to produce proteins that act as safe, effective vaccines.
Laboratory tools: Scientists use engineered DNA and RNA molecules in research, diagnostics, and gene therapy.

Beyond Bacteria: Transforming Plants, Animals, and Humans

Genetic engineering isn’t limited to single-celled organisms. Scientists have developed techniques to change the genetic makeup of plants and animals, influencing how they grow, what traits they express, and how they respond to their environment.

Crops can be engineered to resist pests, tolerate harsh climates, or produce more nutritious food.
Animals can be modified for increased productivity or better disease resistance.
Human medicine now explores gene editing to treat inherited disorders and prevent genetic diseases from being passed on.

Genetic Engineering and the Environment

Biotechnology is also being used to tackle some of our most pressing environmental challenges:

Bioremediation: Engineered bacteria help clean up oil spills, toxic waste, and industrial pollutants.
Soil health: Certain microbes have been modified to enhance nutrient levels in the soil, boosting crop yields.
Eco-friendly pest control: Genetically altered organisms can target and reduce populations of harmful pests without damaging the ecosystem.

Key Takeaways for the Curious Mind

🧬 Genetic engineering allows scientists to directly modify DNA to create organisms with new, beneficial traits.
💉 Biotechnology now enables bacteria to produce medicines, vaccines, and research tools that were once impossible to obtain synthetically.
🌾 Agriculture and food production have been revolutionized by genetically modified plants and animals, increasing yield and reducing waste.
🌍 Environmental benefits of biotechnology include cleaning pollutants, improving soil health, and offering sustainable alternatives to chemical pesticides.
🧠 The future of medicine could include curing genetic diseases at their root—by fixing the DNA itself.