Genetics

Biotechnology & Genetic Engineering: An Overview

Biotechnology is a field of life science that uses living organisms and biological systems to create modified or new organisms or useful products. A major component of biotechnology is genetic engineering.

The popular concept of biotechnology is one of experiments happening in laboratories and cutting-edge industrial advances, but biotechnology is much more integrated into most people’s everyday lives than it seems.

The vaccines you get, the soy sauce, cheese and bread you buy at the grocery store, the plastics in your daily environment, your wrinkle-resistant cotton clothing, the cleanup after news of oil spills and more are all examples of biotechnology. They all "employ" living microbes to create a product.

Even a Lyme disease blood test, a breast cancer chemotherapy treatment or an insulin injection might be the result of biotechnology.

TL;DR (Too Long; Didn't Read)

Biotechnology relies on the field of genetic engineering, which modifies DNA to alter the function or other traits of living organisms.

Early examples of this are selective breeding of plants and animals thousands of years ago. Today, scientists edit or transfer DNA from one species to another. Biotechnology harnesses these processes for a wide variety of industries, including medicine, food and agriculture, manufacturing and biofuels.

Genetic Engineering to Change an Organism

Biotechnology would not be possible without genetic engineering. In modern terms, this process manipulates cells’ genetic information using laboratory techniques in order to change the traits of living organisms.

Scientists may use genetic engineering in order to change the way an organism looks, behaves, functions, or interacts with specific materials or stimuli in its environment. Genetic engineering is possible in all living cells; this includes micro-organisms such as bacteria and individual cells of multicellular organisms, such as plants and animals. Even the human genome can be edited using these techniques.

Sometimes, scientists alter genetic information in a cell by directly altering its genes. In other cases, pieces of DNA from one organism are implanted into the cells of another organism. The new hybrid cells are called transgenic.

Artificial Selection Was the Earliest Genetic Engineering

Genetic engineering may seem like an ultra-modern technological advance, but it has been in use for decades, in numerous fields. In fact, modern genetic engineering has its roots in ancient human practices that were first defined by Charles Darwin as artificial selection.

Artificial selection, which is also called selective breeding, is a method for deliberately choosing mating pairs for plants, animals or other organisms based on desired traits. The reason to do this is to create offspring with those traits, and to repeat the process with future generations to gradually strengthen the traits in the population.

Although artificial selection does not require microscopy or other advanced lab equipment, it is an effective form of genetic engineering. Although it began as an ancient technique, humans still use it today.

Common examples include:

  • Breeding livestock.
  • Creating flower varieties.
  • Breeding animals, such as rodents or primates, with specific desired traits like susceptibility for diseases for research studies.

The First Genetically Engineered Organism

The first known example of humans engaging in the artificial selection of an organism is the rise of Canis lupus familiaris, or as it is more commonly known, the dog. About 32,000 years ago, humans in a an area of East Asia that is now China, lived in hunter-gatherer groups. Wild wolves followed the human groups and scavenged on carcasses that hunters left behind.

Scientists think it is most likely that humans only allowed the docile wolves that were not a threat to live. In this way, the branching off of dogs from wolves began by self-selection, as the individuals with the trait that allowed them to tolerate the presence of humans became the domesticated companions to the hunter-gatherers.

Eventually, humans began to intentionally domesticate and then breed generations of dogs for desired traits, especially docility. Dogs became loyal and protective companions to humans. Over thousands of years, humans selectively bred them for specific traits such as coat length and color, eye size and snout length, body size, disposition and more.

The wild wolves of East Asia of 32,000 years ago that split off 32,000 years ago into dogs comprise almost 350 different dog breeds. Those early dogs are most closely genetically related to the modern dogs called Chinese native dogs.

Other Ancient Forms of Genetic Engineering

Artificial selection manifested in other ways in ancient human cultures, as well. As humans moved toward agricultural societies, they utilized artificial selection with an increasing number of plant and animal species.

They domesticated animals by breeding them generation after generation, only mating the offspring that exhibited desired traits. These traits depended on the purpose of the animal. For example, modern domesticated horses are commonly used in many cultures as transportation and as pack animals, part of a group of animals commonly called beasts of burden.

Therefore, traits that horse breeders might have looked for are docility and strength, as well as robustness in cold or heat, and an ability to breed in captivity.

Ancient societies utilized genetic engineering in ways other than artificial selection, too. 6,000 years ago, Egyptians used yeast to leaven bread and fermented yeast to make wine and beer.

Modern Genetic Engineering

Modern genetic engineering happens in a laboratory instead of by selective breeding, since genes are copied and moved from one piece of DNA to another, or from one organism’s cell to another organism’s DNA. This relies on a ring of DNA called a plasmid.

Plasmids are present in bacterial and yeast cells, and are separate from chromosomes. Although both contain DNA, plasmids are typically not necessary for the cell to survive. While bacterial chromosomes contain thousands of genes, plasmids contain only as many genes as you would count on one hand. This makes them much simpler to manipulate and analyze.

The discovery in the 1960s of restriction endonucleases, also known as restriction enzymes, led to a breakthrough in gene editing. These enzymes cut DNA at specific locations in the chain of base pairs.

Base pairs are the bonded nucleotides that form the DNA strand. Depending on the species of bacteria, the restriction enzyme will be specialized to recognize and cut different sequences of base pairs.

Scientists discovered that they were able to use the restriction enzymes to cut out pieces of the plasmid rings. They were then able to introduce DNA from a different source.

Another enzyme called DNA ligase attaches the foreign DNA to the original plasmid in the empty gap left by the missing DNA sequence. The end result of this process is a plasmid with a foreign gene segment, which is called a vector.

If the DNA source was a different species, the new plasmid is called recombinant DNA, or a chimera. Once the plasmid is reintroduced into the bacterial cell, the new genes are expressed as if the bacterium had always possessed that genetic makeup. As the bacterium replicates and multiplies, the gene will also be copied.

Combining DNA From Two Species

If the goal is to introduce the new DNA into the cell of an organism that is not bacteria, different techniques are required. One of these is a gene gun, which blasts very tiny particles of heavy-metal elements coated with the recombinant DNA at plant or animal tissue.

Two other techniques require harnessing the power of infectious disease processes. A bacterial strain called Agrobacterium tumefaciens infects plants, causing tumors to grow in the plant. Scientists remove the disease-causing genes from the plasmid responsible for the tumors, called the Ti, or tumor-inducing plasmid. They replace these genes with whatever genes they want to transfer into the plant so that the plant will become “infected” with the desirable DNA.

Viruses often invade other cells, from bacteria to human cells, and insert their own DNA. A viral vector is used by scientists to transfer DNA into a plant or animal cell. The disease-causing genes are removed and replaced with the desired genes, which may include marker genes to signal that the transfer occurred.

Modern History of Genetic Engineering

The first instance of modern genetic modification was in 1973, when Herbert Boyer and Stanley Cohen transferred a gene from one strain of bacteria into another. The gene coded for antibiotic resistance.

The following year, scientists created the first instance of a genetically modified animal, when Rudolf Jaenisch and Beatrice Mintz successfully inserted foreign DNA into mouse embryos.

Scientists began applying genetic engineering to a wide field of organisms, for a burgeoning number of new technologies. For example, they developed plants with herbicide resistance so that farmers could spray for weeds without damaging their crops.

They also modified foods, especially vegetables and fruits, so that they would grow much larger and last longer than their unmodified cousins.

The Connection Between Genetic Engineering and Biotechnology

Genetic engineering is the foundation of biotechnology, since the biotechnology industry is, in a general sense, a vast field that involves making use of other living species for humans’ needs.

Your ancestors from thousands of years ago who were selectively breeding dogs or certain crops were making use of biotechnology. So too are modern-day farmers and dog breeders, and so is any bakery or winery.

Industrial Biotechnology and Fuels

Industrial biotechnology is used for fuel sources; this is where the term “biofuels” originates. Micro-organisms consume fats and turn them into ethanol, which is a consumable fuel source.

Enzymes are used to produce chemicals with less waste and cost than traditional methods, or to clean up manufacturing processes by breaking down chemical byproducts.

Medical Biotechnology and Pharmaceutical Companies

From stem cell treatments to improved blood tests to a variety of pharmaceuticals, the face of healthcare has been changed by biotechnology. Medical biotechnology companies use microbes to create new medications, such as monoclonal antibodies (these drugs are used to treat a variety of conditions, including cancer), antibiotics, vaccines and hormones.

A significant medical advance was the development of a process to create synthetic insulin with the help of genetic engineering and microbes. DNA for human insulin is inserted into bacteria, which replicate and grow and produce the insulin, until the insulin can be collected and purified.

Biotechnology and Backlash

In 1991, Ingo Potrykus used agricultural biotechnology research to develop a kind of rice that is fortified with beta carotene, which the body converts to vitamin A, and is ideal to be grown in Asian countries, where childhood blindness from vitamin A deficiency is a particular problem.

The miscommunication between the science community and the public have led to great controversy over genetically modified organisms, or GMOs. There was such fear and outcry over a genetically modified food product such as Golden Rice, as it is called, that despite having the plants ready for distribution to Asian farmers in 1999, that distribution has not yet occurred.

References

About the Author

Rebecca E. received a degree in human development before attending graduate school in writing. She has an extensive background in cognition and behavior research, particularly the neurological bases for personality traits and psychological illness. As a freelance writer, her specialty is science and medical writing. She's written for Autostraddle, The Griffith Review and The Sycamore Review. More information about Rebecca can be found at www.rebeccathewriter.com.