Although the terms genetics and genomics are used interchangeably, it’s important to remember that they do not mean the same thing. Let’s examine the definition of these terms, look at their differences, and understand the importance behind the science.

Definitions

According to the World Health Organization (WHO, 2019):

• Genetics is the study of heredity.
• Genomics is defined as the study of genes and their functions, and techniques related to this study.

Examples of genetic or inherited disorders include cystic fibrosis, Huntington's disease, sickle cell anemia, Von Willebrand Disease, and phenylketonuria (PKU). Genomics refers to the scientific study of complex diseases such as heart disease, asthma, diabetes, and cancer. These diseases are typically caused by a combination of genetic and environmental factors than by individual genes. Genomics offers new promises for treatments and therapies for some complex diseases, as well as new diagnostic methods.
 
So, while genetics closely examines the operation and configuration of the single gene, genomics addresses all genes and their interrelationships with the intention of identifying their combined influence on the growth and development of the organism.

A Closer Look (The Jackson Library, 2019; NIH, 2018; NIH, 2019)

In genetics, we analyze the way certain traits or conditions are passed down from one generation to another through deoxyribonucleic acid (DNA). You might recall from your school days that genetics dates back to scientist and Augustinian friar, Gregor Mendel, who studied heredity in pea plants in the mid-1800s. A gene is a unit of DNA located on a chromosome that determines your characteristics. Your genes direct body development, cause disease, and respond to medication.
 
DNA is stored as a code made up of four chemical bases that include adenine (A), guanine (G), cytosine (C), and thymine (T). Human DNA has about 3 billion bases, and more than 99% of the bases are the same in all people! It’s important to remember that the order of the bases influences the information available for building and maintaining an organism. DNA bases pair up and each is attached to a sugar molecule and a phosphate molecule. This whole “package” is called a nucleotide. Nucleotides are assembled in two long strands that form a spiral called a double helix (looks like a ladder). DNA replicates or makes copies of itself. Each strand of DNA can be a pattern for duplicating the sequence of bases.
 
Genomics was first described by scientist Dr. Tom Roderick at the Jackson laboratory in Maine in 1986 to encompass sequencing, mapping, and new technologies in the field of genetics. With genomics, the entirety of an organism’s genes, also known as the genome, is studied. Researchers study vast amounts of DNA-sequence data (3 billion units of DNA across 23,000 genes) to find differences that cause disease or cause a response to treatments.

What’s the Importance? (NIH, 2018)

Genomics helps us understand why some individuals become ill from certain infections, environmental factors, and behaviors, while others do not. An example of this is a person who exercises regularly, eats a healthy diet, and has regular checkups, but dies of a heart attack at age forty. Another example is of a person who smokes cigarettes over a lifetime, but lives into their nineties. Interestingly, genomic factors play a role in nine of the ten leading causes of death in the United States. It is amazing to think that every person is 99.9% identical in their genetic makeup, with 0.1% holding clues about the causes of diseases (Rosenberg et. al, 2002).  
 
In general, genetics and genomics both play a vital role in our overall state of health and development of disease. If you have ever used a genetic testing services (i.e. 23andme, AncestryDNA®), you know these can help you learn about inherited conditions, screening, testing, and treatment.
 
Genomics may assist us in improving our health and help us understand what we can do to prevent the onset of some diseases. Since our health is shaped by our family history and environmental influences, understanding these factors can help us recognize factors for conditions that also have a genetic component.
 
Additional Resources
National Institutes of Health (NIH) Genetics Health Reference
National Institutes of Health (NIH) Genetic and Rare Disease Center
 

References:
National Institutes of Health (NIH). (2018). Genetics vs. Genomics Fact Sheet. Retrieved from https://www.genome.gov/about-genomics/fact-sheets/Genetics-vs-Genomics
 
National Institutes of Health (NIH). (2019). What is DNA? Retrieved from https://ghr.nlm.nih.gov/primer/basics/dna
 
Rosenberg, N., Pritchard, K., Weber, J., Cann, H., Kidd, K., Zhivotovsky, L., Feldman, M. (2002). Genetic Structure of Human Populations. Science, 298(5602). doi: 10.1126/science.1078311
 
The Jackson Library. (2019). Genetics vs genomics. Retrieved from https://www.jax.org/personalized-medicine/precision-medicine-and-you/genetics-vs-genomics
 
World Health Organization (WHO). (2019). Human Genomics in Global Health. Retrieved from https://www.who.int/genomics/geneticsVSgenomics/en/