1.2 Genetics and Genomics Introduction

Understanding Genomics

Genetics and Genomics – What’s the Difference?

Genetics and genomics both play roles in health and disease. Genetics refers to the study of genes and the way that certain traits or conditions are passed down from one generation to another. Genomics describes the study of all of a person’s genes (the genome).

Genetics is a term that refers to the study of genes and their roles in inheritance – in other words, the way that certain traits or conditions are passed down from one generation to another. Genetics involves scientific studies of genes and their effects. Genes (units of heredity) carry the instructions for making proteins, which direct the activities of cells and functions of the body. Examples of genetic or inherited disorders include cystic fibrosis (See: Learning About Cystic Fibrosis), Huntington’s disease (Learning About Huntington’s Disease), and phenylketonuria (PKU) (Learning About Phenylketonuria).

Genomics is a more recent term that describes the study of a person’s genes (the genome), including interactions of those genes with each other and the person’s environment. Genomics includes the scientific study of complex diseases such as heart disease, asthma, diabetes, and cancer because these diseases are typically caused more by a combination of genetic and environmental factors than by individual genes. Genomics offers new possibilities for therapies and treatments for some complex diseases and new diagnostic methods.

Personalized medicine (or healthcare) is an emerging practice that uses an individual’s genetic profile to guide decisions made regarding disease prevention, diagnosis, and treatment. Knowing a patient’s genetic profile can help doctors select the proper medication or therapy and administer it using the appropriate dose or regimen. Personalized medicine is being advanced through data from the Human Genome Project.

Personalized medicine is a fantastic opportunity to take a “one size fits all” approach to diagnostics, drug therapy, and prevention and turn it into an individualized approach. We all are similar, of course, but we are also different. The idea that medicine would be applied in a fashion that ignores those differences can’t be any more correct than going to the shoe store and buying any old pair of shoes without checking the size. Genomics plays a significant role in the emergence of personalized medicine as it gives us a window in a particular molecular way into those differences between us and allows the opportunity for making individual predictions about disease risk that can help somebody choose a prevention plan that is right for them. It also allows the possibility, in some instances, of picking the right drug at the right dose for the right person instead of the “one size fits all” approach to drug therapy. And ultimately, it will be hard to see how any kind of medicine will not be affected by this as we learn more and more about the individual and as many of us find our complete genomes being sequenced and placed into our medical records to empower that kind of personalized approach. Lots of work to do here, but it may be the biggest revolution in medicine in a very long time.

Precision medicine is a newer term with a similar meaning to the often analogously used “personalized medicine or healthcare.”  The shift away from the word personalized was in response to concerns over misinterpretation of the word “personalized” to imply that each individual could have uniquely tailored care and treatment. Precision medicine/healthcare takes advantage of large data sets of individuals such as their genome or their entire electronic health record to tailor their healthcare to their unique attributes. “Precision medicine consists of identifying which approaches/treatment will be effective for which patients according to the group to which they belong based on their biological characteristics. In this sense, it is more stratified medicine than personalized medicine” (Delpierre & Lefèvre, 2023). It is common sense that no two individuals are the same, so they should not get the same healthcare. Precision healthcare embodies that simple idea.

The Human Genome Project

The Human Genome Project (HGP) is one of the most remarkable scientific feats in history. The project was a voyage of biological discovery led by an international group of researchers looking to comprehensively study all of the DNA (known as a genome) of a select set of organisms. Launched in October 1990 and completed in April 2003, the Human Genome Project’s signature accomplishment – generating the first sequence of the human genome – provided fundamental information about the human blueprint, which has since accelerated the study of human biology and improved the practice of medicine.

Checkout this Human Genome Project timeline of events from the NHGRI

Visit NHGRI to learn more about the Human Genome Project.

Facts About the Human Genome

• Humans have approximately 20,000 genes
• DNA contains 6 billion nucleotides, which amounts to 3 billion base pairs.
• There is a 99.9% similarity in the DNA sequences of humans.
• A human gene may have 1-3 letters that differ from person to person.
• Humans have 23 pairs of chromosomes

Watch History – Making Sense of the Human Genome (4 mins) on YouTube

Genomics Applications

Why Are Genetics and Genomics Important to Health?

Genetics and genomics both play roles in health and disease. Genetics helps individuals and families learn about how conditions such as sickle cell anemia and cystic fibrosis are inherited in families, what screening and testing options are available, and, for some genetic conditions, what treatments are available.

Genomics is helping researchers discover why some people get sick from certain infections, environmental factors, and behaviours while others do not. For example, some people exercise their whole lives, eat a healthy diet, have regular medical checkups, and die of a heart attack at age 40. Some people smoke, never exercise, eat unhealthy foods and live to be 100. Genomics may hold the key to understanding these differences.

Apart from accidents (such as falls, motor vehicle accidents or poisoning), genomic factors play a role in nine of the ten leading causes of death in the United States (for example, heart disease, cancer and diabetes. See: Leading Causes of Death). All human beings are 99.9 percent identical in their genetic makeup. Differences in the remaining 0.1 percent hold important clues about the causes of diseases. Gaining a better understanding of the interactions between genes and the environment using genomics is helping researchers find better ways to improve health and prevent disease, such as modifying diet and exercise plans to prevent or delay the onset of type 2 diabetes in people who carry genetic predispositions to developing this disease.

Why Are Genetics and Genomics Important to the Health of Families?

Understanding more about diseases caused by a single gene (using genetics) and complex diseases caused by multiple genes and environmental factors (using genomics) can lead to earlier diagnoses, interventions, and targeted treatments. A person’s health is influenced by their family history and shared environmental factors. This makes family history an important, personalized tool that can help identify many of the causative factors for conditions with a genetic component. The family history can serve as the cornerstone for learning about genetic and genomic conditions in a family and for developing individualized approaches to disease prevention, intervention, and treatment.

Genomic Literacy

What exactly is meant by “genomic literacy?”

Evidence Informing the Definition of Genomic Literacy

Boerwinkel et al. (2017) conducted a Delphi study to achieve expert consensus on the essential knowledge required for informed decision-making in genomics. Genomic literacy is necessary not only for healthcare professionals delivering genomic services but also for patients receiving them. The authors classified this knowledge into three categories:

Conceptual knowledge: knowledge of genetic concepts;

Sociocultural knowledge: knowledge of how applications of genetic technologies are used in societal activities and in what ways they influence human lives;

Epistemic knowledge: knowledge of the meaning of genetic information. This concerns the knowledge needed to interpret genetic information from different sources and how to use these in argument and decision-making. This knowledge includes Nature of Science aspects such as the certainty and uncertainty of genetic information and how genetic concepts have evolved (Boerwinkel et al., 2017, p.1106).

How Can Genomic Literacy Assist Nurses in Addressing the Social, Ethical, and Equity Issues Associated with Nursing?

Attribution & References

Except where otherwise noted, content on this page is adapted from the following sources.

• Genetics vs. Genomics Fact Sheet, Courtesy of: National Human Genome Research Institute, Public Domain with attribution
• Personalized Medicine, Courtesy of: National Human Genome Research Institute, Public Domain with attribution
• Precision Medicine, Courtesy of: National Human Genome Research Institute, Public Domain with attribution
• 15 Ways Genomics Influences Our World, Courtesy of: National Human Genome Research Institute, Public Domain with attribution
• H5P/video from 10.3 Genomics and Proteomics In Concepts of Biology – 1st Canadian Edition by Charles Molnar and Jane Gair, CC BY 4.0

Adaptations include combining sources, minor grammatical changes, and addition of quotes, videos and commentary to improve student understanding.

References

Boerwinkel, D.J., Yarden, A. & Waarlo, A.J. (2017). Reaching a consensus on the definition of genetic literacy that is required from a twenty-first-century citizen. Science & Education, 26, 1087–1114. https://doi.org/10.1007/s11191-017-9934-y

Delpierre, C., & Lefèvre, T. (2023). Precision and personalized medicine: What their current definition says and silences about the model of health they promote. Implication for the development of personalized health. Frontiers in Sociology, 8, 1112159. https://doi.org/10.3389/fsoc.2023.1112159