What is Genetics?
Put simply, genetics is the study of heredity, or how genes are passed down from one organism to another through their genetic information. It involves the study of genetic material like DNA and how different genes impact the phenotype (or physical traits) of an organism.
Gregor Mendel is often said to be the father of genetics. Mendel performed studies on inheritance in pea plants by crossing plants with different traits and observing the traits of the offspring they produced. Although Mendel had no inkling of genes or the structure of DNA, his relatively simple experiments formed the jumping off point for our modern understanding of genetics.
Scientists eventually concluded that the DNA found in a cell’s nucleus was the material responsible for passing genes on to offspring. In 1953, James Watson and Francis Crick (with major contributions from Rosalind Franklin) discovered the double helix structure of DNA. This opened the door to a much more detailed understanding of how and why genes and DNA affect individual traits and heredity.
To understand genetics you have to understand DNA. DNA is contained in the nucleus of every cell in our body, and is divided up into 23 pairs of chromosomes (except in gametes, or cells for sexual reproduction), which are long, tightly coiled strands of DNA. Half of these chromosomes come from one parent and half from the other.
Chromosomes contain genes, or sections of DNA that code for particular physical traits (or parts of physical traits). For example, some genes determine a person’s eye color or height, while others might make someone more likely to go bald in middle age or develop a particular disease. It is estimated that humans have up to 25,000 genes, and we still don’t know what many of them are for.
Just like chromosomes, we have one copy of each gene from each of our parents (so two copies total). It is the interaction between these two gene copies that ultimately determines our physical makeup.
In addition to being fascinating and allowing us to learn more about ourselves, the study of genetics also has many practical applications. Genetic testing can be used to determine whether two people are biologically related, or it can let people know whether they are at a higher risk for certain diseases. Lately, at-home genetic testing kits like 23 and Me and Ancestry have allowed people to learn more about their genes, locate lost family members, and have even been used to find fugitive criminals through their relatives.
Lachmann-Anke, Peggy and Marco (artists). (2016). DNA White Male 3D Model [digital art]. Retrieved from