Genetics Analogies

The Genome as the Harry Potter Series

Written by Kelly A. Hogan, University of North Carolina at Chapel Hill

The genetic code is often described as being analogous to the written language. I expand this analogy to help students understand the hierarchy that exists in genetics, since I find many students don’t understand the relationship between a gene and a chromosome. Imagine a set of books, perhaps the Harry Potter series. The entire series on the shelf is analogous to the genome. Each book can be thought of as a chromosome. Within each book are chapters, these can be thought of as genes. Lastly, the 26 letters of the alphabet are arranged to make the variation of words within the genes. The genetic code has 4 letters to make unique arrangements/sequences. What would be the consequence if a few sentences or a chapter or an entire book was lost from the series? Would the story still make sense? (This would be analogous to mutations and chromosomal abnormalities.)

Pairs of Shoes and Pairs of Chromosomes

Written by Kelly A. Hogan, University of North Carolina at Chapel Hill

When discussing homologous chromosomes and sister chromatids, I often use analogies to shoes or socks. For example, I may have two pairs of the same cute flats, one pair in yellow and one in turquoise. These flats are the same size, same brand, exact same style. The yellow shoes are like sister chromatids to each other, just as the turquoise shoes are sister chomatids with each other. The yellow and turquoise are like homologs to each other. To carry the analogy further, I ask them what a pair of running sneakers might be analogous to. (These would be a completely different chromosome.)

Losing Control of a Car Relates to Unregulated Cell Division

Written by Kelly A. Hogan, University of North Carolina at Chapel Hill

When discussing the cell cycle and cancer causing genes, I often use an analogy to cars. There are two ways to lose control of a car: the gas pedal can get stuck down or the brakes will not work when engaged. In either case, the car speeds along without driver control. In this anology, tumor supressors are like brakes, which normally prevent the cell cycle from losing control (preventing cancer). When mutated, the brakes are lost and the cell divides out of control. Proto-oncogenes are like the gas pedal, in that they promote cell division. When mutated, like a gas pedal stuck down, they cause unregulated cell division.