After the completion of the human genome project, the field of genetics began to gain popularity and intrigue with the general public. Genetics, as a field, has been explored since the early 19th century, beginning with Imre Festetics, a long forgotten predecessor to Gregor Mendel, but it wasn’t until recently that it became center stage in our everyday lives-everything from disease, ancestry, medicine, and personality are wrapped up in genetics. This makes sense when you view genes as personal codes: encoding what eye color we have, which hand we write with, and which diseases we are prone to getting. Our genes encode our existence in a very real way, so understanding genetics leads to a better understanding of what it means to be human and what it means to be us.
Genetics can be a daunting and even scary field to study, but now that genetic engineering and personalized medicine are being covered by media and discussed online, it’s time for the general public to have a solid understanding of what genetics is and especially how their own genetics affect them. This is the beginning of a 3-part series regarding genetics and genetic engineering. This first post will cover an overview of genetics and genetic engineering. The next two will discuss tools and techniques used for genetic engineering, such as CRISPR, and the more controversial side of genetics, such as “designer babies” and genetically modified organisms.
What is genetics?
Instead of repeating most of the information that is available online or in text books, I thought it would be more efficient to share some links that I believe cover the topic of genetics well. Understanding genetics is essential to understanding genetic engineering, so before proceeding to the next section I highly recommend checking out at least one of the following links:
- University of Utah’s Learn Genetics: an interactive and in-depth overview of genetics
- Merck Manual: overview of genetics and chromosomes
- National Geographic: simplified overview of genetics
Genetic Engineering: An Introduction
Genetic engineering may seem like a new 21st century technology, especially with its recent boom in media coverage and controversy, but the concept has been in the scientific community since the 70’s and is in fact a naturally occurring process. The technology used for genetic engineering began to form in 1973 when Herbert Boyer and Stanley N. Cohen performed the first successful genetic recombination experiment. Together they were were able to combine two separate plasmids-carriers of genes-and clone the new recombined plasmid into E. coli. The recombined plasmid was functional and provided the E. coli with genes resistant to both tetracycline and kanamycin, both antibiotics. This same process occurs naturally in bacteria, usually with the assistance of viruses (see my previous post for an explanation), and this is why we have “antibiotic resistant” strains of bacteria.
Speaking of naturally occurring cases of genetic engineering, there is the case of the sweet potato. Several studies, including one at the International Potato Center in Lima, Peru, have found that sweet potatoes were genetically modified by bacteria approximately 8,000 years ago. Bacteria, such as Agrobacterium, are present in soils and act like a virus by injecting plant cells with their genes. Once these genes are inside the plant cells, they produce proteins within the plant-effectively changing that plant. Researchers from Peru believe that the modifications caused from the bacterial genes helped make sweet potatoes more edible for humans. Today sweet potatoes are the 7th most important crop in the world according to the Agriculture Organization of the United Nations.
So, what is genetic engineering? And is it all the same? The simple answers are: modification of an organism by the insertion of a functional gene from a different organism, and no. But this isn’t a subject that can boiled down to black and white, or right and wrong, and one that not only requires, but deserves to be looked at in depth. So, with that being said, let’s begin by describing what genetic engineering is.
Defining Genetic Engineering:
Genetic engineering, or genetic modification, can be done using several different processes, but the basic purpose is the same: to alter an organism on the genetic level, by either inserting or removing a gene. The gene could come from the same type of organism (i.e. E. coli to E. coli) or from different organisms, such as the follow-up experiment done by Boyer and Cohen which consisted of taking a gene from the African clawed frog, Xenophs laevis, and inserting it into E. coli.
Genetic engineering is commonly divided into two categories: modification using biotechnology (traditional genetic engineering), or modification through selective breeding or other forms of artificial selection. The latter is often not considered genetic engineering at all, but on the genetic level, they are actually quite similar processes. This will be explained further in the next post.
In order to get a better understanding of genetic modification and the processes used to achieve it, some common terms need to be defined first. When genetic material, either RNA or DNA, is taken from two different organisms and combined together it is considered recombinant nucleic acid (DNA or RNA). When the recombinant nucleic acid is successfully inserted into an organism, that organism is either termed transgenic, if the material came from a different type of organism, or cisgenic, if the material came from the same type of organism. While transgenic and cisgenic are commonly used in the scientific community, the more popularized term for any genetically altered organism is genetically modified organism (GMO). Alternatively, organisms can have a gene “knocked out”, or made non-functional, through gene knockout techniques and these organisms are referred to simply as knockout organisms.
Genetic engineering also has roots in stem cell and cell cloning science, but for the purpose of these posts I’ll be concentrating on the modification of plants and animals through traditional genetic modification and artificial selection. In the second post of this series, I’ll be discussing the tools and actual processes used to create modified organisms. Until then, brush up on your genetics, and enjoy some sweet potatoes.
To Be Continued..