In the article Unwinding Genetic Dogma: New Study Reveals Yin Yang At Work in Human Genes, I highlighted a recent study led by scientists at Thomas Jefferson University in Philadelphia that provides evidence that human cells write pieces of RNA back into DNA code, a process previously thought impossible. But the conversion of RNA Messages into DNA code is nothing new for people familiar with pathogenic microorganisms, virology, and a unique class of viruses called retroviruses.
Decades ago, the discovery of retroviruses already had begun to help revise the traditional central dogma of molecular biology and its touted unidirectional flow of genetic information. These enveloped single-stranded RNA viruses are named retro because they reverse the typical flow of genetic information, from RNA to DNA, in the following manner:
RNA → DNA → RNA → proteins
Retroviruses contain a special enzyme called reverse transcriptase that is used to generate complementary DNA (cDNA) from an RNA template in a process called reverse transcription or retrotranscription. With the exception of hepatitis B virus (HBV) and a few other non-retroviral viruses, viruses that rely on retrotranscription are called retroviruses.
Only a limited number of human retroviruses have been discovered, including human T-cell leukemia or lymphotropic virus type 1 and 2 (HTLV-1, HTLV-2) related to cancer leukaemias and lymphomas, and human immunodeficiency virus type 1 and 2 (HIV-1, HIV-2) related to acquired immunodeficiency syndrome (AIDS).
While retroviruses are excellent hijackers of cells, they are in fact a very important part of the human species. Scientists have estimated that up to a whopping 8% of DNA in human cells is retroviral in origin.
Resulting from ancient infections caused by now extinct retroviruses, scientists believe this retroviral material has helped shape the body's innate immune response, our birth-given first line of defense against pathogens before they can start an infection.
Although most of this retroviral material now lies dormant, recent research suggests it has played a far bigger role than just shaping our response to external pathogens. This retroviral material appears to have also played a crucial part in the shaping and evolution of the human genome, and it has contributed to establishing very specific patterns of gene expression.
Recent research also suggests that pieces of this genetic retroviral graveyard may still be recognized as viral components by our immune system. Elevated expression of this retroviral material has been associated with a variety of autoimmune disorders, neurological diseases, and cancers.
Supported by this new research and the overwhelming percentage of retroviral genetic information in human cells, retroviruses are now being used within an emerging frontier in biomedical science called precision medicine.
What is Precision Medicine?
Precision medicine is a new model of medicine that proposes customizing healthcare with medical decisions, treatments, practices, or products that are tailored to a subgroup of patients. Instead of a one‐drug‐fits‐all model, precision medicine looks at the genes, environments, and lifestyles of people in order to select treatment that could work best for them.
But in reality, precision medicine largely focuses on targeting treatments for unique genetic profiles, and this is why it is sometimes also referred to as genomic medicine.
At the heart of precision or genomic medicine are retroviruses. Without losing its regulating signals, genes from retroviruses can be spliced and replaced with just about any DNA sequence. The new 'hybrid' retrovirus can then be released into the host and be delivered at various targeted sites throughout the targeted genome.
An important component of precision medicine is the reverse transcription-polymerase chain reaction (RT-PCR) test. These tests use retroviral RNA as starting material for in vitro nucleic acid amplification. Originally they were designed for forensic applications in law enforcement relating to paternity and crime scene investigations. They would later be applied in genetic detection of diseases such as cancer.
Recently during the coronavirus pandemic of 2020, several biotech companies developed test kits and machines that leveraged the RT-PCR testing process in an effort to identify the COVID-19 genome in a patient's sample. Although several problems and limitations have been reported with the RT-PCR test, moving forward it appears it will become a new medical testing standard for a wide variety of applications in 21st Century medicine.
CRISPR Tool & Superhero Gene Therapy
Another important component of precision medicine are gene editing tools that, similar to word processing software, can precisely alter and rearrange DNA. One such tool, called Clustered Regularly Interspaced Short Palindromic Repeats, or CRISPR, features an "autocorrect" feature to automatically make corrections to one or more letters of DNA.
To ensure the CRISPR gene editing tool is delivered to the right parts of the body safely and is not destroyed by the immune system, it is commonly carried by... you guessed it— retroviruses.
Gene editing tools like the CRISPR are not new but they remain relatively untested in humans. However within the next decade, ongoing advances in CRISPR will give rise to the potential of rewriting a disease prone segment of DNA to a disease resistant version, promising a revolutionary new approach in the treatment and prevention of various diseases, from infections to cancers.
Speculation is already surrounding the development of a "superhero" injection that could deliver health and performance enhancing DNA code that is more disease resistant from the bodies of centenarians, olympians and world class athletes into the bodies of those of the average person with more disease prone DNA.
Precision medicine and the use of retroviruses to splice and edit genes is a very new and still developing field in medicine that promises to revolutionize healthcare. Using retroviruses in this way, theoretically any DNA segment in any cell type can be targeted and replaced, inviting the idea of massive potential for treating and preventing infections, genetic-type diseases and cancers, as well as autoimmune diseases and diseases of the nervous system.
However there is still much to be done in terms of ensuring the technology is safe. With the third leading cause of death in the US already being attributed to errors in medical decision making and wrongful and negligent use of medicine, the technology must above all be proven safe for consumers before it is rolled out to the masses.
The technology also involves some major social and ethical issues, as the system could be used by one sociopathic person or group of people to sculpt genetic architecture of human embryos deemed superior, or as a means to create bioweapons that cause pandemic disease and death on a global scale.
Even if these issues are addressed, editing and splicing genes in the effort to somehow create an improved "superhero" human is misanthropic and surely a fool's errand that will likely not end well. Science has repeatedly proven that we know very little about the human species, let alone our genes.
Say for example that human DNA were to be genetically modified to withstand cancer— cancer may be edited out of the human genome, but what would this splicing do to our resistance to anemia, the common cold, malaria, etc? Where would this endeavor end? The expression "cutting your nose to spite your face" certainly applies here.
Beyond that, science has also repeatedly shown that relying on your own genetics will react favorably when limiting exposure to harmful environmental toxins and pathogens, eating a nutritious plant-based diet, leading a balanced lifestyle, and most importantly— having a positive mental attitude and surrounding yourself with love and happiness in all aspects of your life.
While scientists continue searching for a way to control nature, you can rest assured that you have been given everything you need to be as naturally healthy as possible without the use of editing and splicing your genes by way of retroviruses.
Instead of hoping science may one day help mutate your genes and turn you into a some sort of "superhero", ask yourself what things are you doing right now in your own life to maximize this potential that already exists inside of you?
You already are a "superhero" in many more ways than you know and better get on with fulfilling your purpose— life won't wait.
- Dewannieux, M. & Heidmann, T. (2013). Endogenous retroviruses: acquisition, amplification and taming of genome invaders. Current Opinion in Virology, 3,(6). https://doi.org/10.1016/j.coviro.2013.08.005.
- Feschotte, C. and Gilbert, C. (2012). Endogenous viruses: insights into viral evolution and impact on host biology. Nature Reviews Genetics, 10. https://doi.org/10.1038/nrg3199 .
- Grandi, N. and Tramontano, E. (2018). Human Endogenous Retroviruses Are Ancient Acquired Elements Still Shaping Innate Immune Responses. Frontiers in Immunology, 10. https://doi.org/10.3389/fimmu.2018.02039 .
- Saini, S. K., et al. (2020). Human endogenous retroviruses form a reservoir of T cell targets in hematological cancers. Nature Communications, 11. https://doi.org/10.1038/s41467-020-19464-8 .
- Skalka, Anna Marie. (2018). Discovering Retroviruses: Beacons in the Biosphere. Cambridge, Massachusetts: Harvard University Press.
- Stoye, J. P. (2012). Studies of endogenous retroviruses reveal a continuing evolutionary saga. Nature Reviews Microbiology, 10. https://doi.org/10.1038/nrmicro2783 .