The combination of an egg and sperm allows for 64 trillion possible chromosome combinations. With that kind of genetic variation, it is highly unlikely you will meet your exact genetic duplicate any time soon. Although it is fun to imagine finding your doppelganger, this genetic variation is the foundation of evolution and is essentially what keeps the human race thriving.
Technically, even identical twins do not stay genetically identical for their entire lives. Though they will always be an exact genotype match, variations will eventually develop in their phenotypes. As a refresher, your genotype is the set of genes responsible for a trait and your phenotype is the expression of that trait. So, if one identical twin develops a genetic disease such as Parkinson’s, cancer, or diabetes, but the other twin does not, it is safe to assume that phenotype variation played a role.
While the scientific world has known for some time that environmental factors have an impact on gene expression, most research is focused on what caused the unhealthy twin to contract a disease or disorder. At the Pacific Northwest Research Institute (PNRI), our team of scientists is redefining genetic research by working to understand how the healthy twin’s body avoided developing the disease in the first place.
How Your Environment Affects Your Health
Most human disease results from interactions between genetic and environmental factors. We know that what a person eats, pollutants in the air they breathe, or how much sleep they get will, over time, alter their phenotype, impacting their susceptibility to disease. The study of environmental impacts on gene variation — and ultimately on gene expression — is called epigenetics.
Unfortunately, the development of disease in humans is nearly impossible to study in a lab setting until the disease is present. That is why the Nadeau Lab at PNRI, led by Joseph Nadeau, PhD, uses mouse models to study the genetic, epigenetic, and systems control of human disease. Genetically defined lab mice provide a unique opportunity to study the ways genes are impacted by the environment through a full life cycle and across generations.
A Breakthrough Spanning Generations
The Nadeau Lab was the first to discover evidence that someone who is not considered at risk for genetic predisposition to a disease could develop a risk for that disease as a result of ancestral exposure to environmental elements.
So even though you might never discover a long-lost genetic twin, PNRI’s research could someday offer the next best thing: a clearer understanding of how your environment and your genetics interact to affect your health.