2.2) The History and Applications of Genetic Testing
Mendelian genetics, a simple model of genetic inheritance created by hybridizing pea plants, was originally developed by Gregor Mendel in the 1860s. In 1953, James Watson and Francis Crick first described the double helix structure of DNA and expanded the understanding that DNA held the hereditary material that was the building block of life.
Early research into the inheritance of athleticism was performed during the 1968 Olympic games in Mexico where researchers investigated 1265 competitors using basic methodologies available to them, including karyotyping (examining chromosomes). During the 1976 Olympic games in Montreal genetic frequencies were collected.
Following Hiroshima, it became clear that there needed to be an efficient way to study long-term DNA damage caused by radiation. In 1990, the Human Genome Project was launched. The project set out to sequence the 3 billion bases of human DNA. In 2003, the project was completed at a cost of $3 billion dollars. That was the first time the entire human genome had been sequenced and it became the foundation for rapid advances in genomics.
Since then, advances in DNA research and technology have been increasing exponentially. Researchers have found over 6,000 genetic disorders and learned that there are approximately 10-30 million genetic differences that make each person unique.
From 2008-2015, the 1000 Genomes Project created a public catalog of human genetic diversity with 2504 people from 26 populations. These projects help inform ongoing research.
Genetic Testing
Genetic testing is a relatively new tool. Genetic testing is the process by which a person’s DNA is analyzed for the presence of particular DNA sequences that encode for traits of interest. Genetic testing is used to detect inherited mutations or variations.
Even 10 years ago, genetic testing was out of reach due to cost. Lucky for us, advances in biotechnology have now made genetic testing widely accessible. You can now do limited to extensive genetic testing for under a hundred to just over a thousand dollars.
The increasing focus by governments of various countries, to regulate and create awareness regarding genetic tests, has successfully resulted in the faster adoption of these tests and increasing research and development funding. It is revolutionizing health and medicine.
These are examples of how genetic testing can be used in a medical setting:
Family planning
- Before starting a family to determine carrier status for certain heritable diseases, like cystic fibrosis.
- In prenatal care, pregnant women now have the option to check for chromosome aberrations in the fetus through a simple blood draw instead of a more dangerous amniocentesis.
- For prenatal diagnosis, most frequently to detect abnormalities in chromosome number. A deviation such as an extra copy of chromosome 21, leads to the development of Down’s syndrome.
Risk screening
- To detect common mutations, present in certain conditions like breast cancer.
- To screen for diseases including Cystic Fibrosis, Sickle Cell Anemia, Duchenne Muscular Dystrophy, Thalassemia, Huntington’s disease, Fragile X Syndrome and Tay-Sach’s disease.
Cancer genetics
- In cancer medicine, physicians can now sequence a patient’s tumor to identify the best treatments.
Pharmaceuticals
- With prescriptions, more than 100 different FDA-approved drugs are now packaged with genomic information that tells doctors to test their patients for genetic variants linked to efficacy, dosages or risky side-effects.
Paternity and crime identity
- For paternity tests and crime scene investigation.
Genetic testing was originally offered in medical settings. While genetic testing was previously only available in medical settings, it is now becoming available via direct-to-consumer in many areas.
Applications of direct-to-consumer genetic testing include:
Disease susceptibility
- Susceptibility to chronic disease (e.g., age-related macular degeneration, Celiac disease, Parkinson’s disease, Alzheimer’s disease).
Preventative health and traits
- Nutritional and metabolic assessments (e.g., macronutrient and micronutrient metabolism, food tolerance, concussion and sports injury risk, inflammation).
- Individual traits or characteristics (e.g., bitter taste perception, earwax type).
Ancestry
- Ancestry information (e.g., where your ancestors came from).
Pharmacogenetics
- Which pain or depression medication will be most effective based on your genetics.
Genetic testing provides risk-assessment information, can promote awareness of genetic conditions and allow consumers to take a more proactive role in their health. Depending on the purpose of the test, genetic testing results may confirm a diagnosis, identify an increased risk of developing a condition in the future, indicate the person is a carrier of a particular genetic variation, or suggest a need for further testing.
During the last decade genetic testing companies has increased significantly. More than 250 genetic testing services are available including dnaPower, 23andMe, Ancestry.com and FamilyTreeDNA to name a few. With these companies advertising regularly through TV and social media, it is increasing consumer awareness and comfort with genetic testing. This growth has been driven by the rapidly declining costs for collecting and analyzing genome data and the public’s growing interest. Estimates suggest that the genetic testing market will be worth approximately $15 billion by 2026 (Mordor Intelligence, 2020).
It is encouraging to see the application of genetic testing now growing in preventative health. That will be the focus of this course – the application of genetic testing to diet, fitness and health. The use of DNA information will continue to grow as it becomes more affordable and accessible.
Increasing education about genetic testing can help to use it in a meaningful way to enable individuals to make informed decisions. Although genetic variations cannot be altered, learning about genetic risk can help people modulate risk by implementing lifestyle changes, such as dietary restriction or supplementation, more frequent screenings, refraining from medications with potential adverse effects, or avoiding chemicals that enhance risks. Ultimately, these decisions can improve health and quality of life.
In this course we will strive to inform you about the use of genetic testing to optimize diet, fitness, and health. This is a new and exciting field and studies are ongoing. Let’s dive in to see what the research in this field has found so far.