Squib Genes vs. Wizard Genes: A Battle for Dominance

Photo by JP Barnaby

In “The Genetics of Harry Potter,” Saturday 1PM in Marriott A601–602, charismatic and down-to-earth Duke professor Eric Spana, PhD, gave a fantastic layman’s breakdown of how we can genetically determine whether offspring in a family could be magical or non-magical. He was specific on acceptable sources of character lineage, which included the Harry Potter novels and movies, tangential books such as Fantastic Beasts and Where to Find Them, the Pottermore website, and of course JK Rowling’s twitter feed. Sources he wouldn’t accept were such content as blogs, quotes, hearsay, and fan fiction.

Spana began the talk with a basic biology lesson on which the subject matter would be based. Human beings have twenty-three pairs of chromosomes, and of that pair, one comes from the mother and the other from the father. He then went on to explain mutations such as one in the MC1R gene which causes a person to have red hair. This logic was supported by an analysis of the Potter family:

Graphic by JP Barnaby

To explain the genetics of wizarding, he introduced two special genes—the wizarding gene and the squib gene. If one wizarding chromosome is passed down, the child will be a wizard. Conversely, if the squib gene is passed, the child will be a squib. So, if we look at the genetics of the Finnegan family:

Graphic by JP Barnaby

However, these situations don’t explain muggle-born children whose parents have no wizarding gene. In those very rare cases, a mutation in the sperm is responsible for wizarding ability. To show how rare, Spana did a study on muggle born students identified at Hogwarts compared to the total number of births in the UK and found that a child of non-magic parents has a 1:750,000 chance of being born a wizard. A person has a better chance of winning the lottery than being a muggle-born wizard.

Squibs, however, are even more rare. When the parents have magic, each of those parents will pass a magic chromosome to the child. If only one chromosome is needed to make magic, then how can those chromosomes be passed, but the progeny not be magical? He explained it with enhancers in the cell that turn on a mutation to block the wizard gene. The mutation results in the squib gene producing no RNA and no proteins.

The questions for this panel were well-reasoned and on target, including a discussion on why muggles are so prevalent if the magical gene is easily passed. One great theory comes from population density. Most wizards inhabit wizarding villages and stay within their own communities. Once a muggle marries a wizard or a child of non-magic parents is born, they are also brought into those communities and out of the general muggle population. Another questioner discussed epigenetics and how environmental factors affect magical ability. For this analysis, he questioned how environmental factors influence the control a wizard has over magic. He attributed the explosive lack of control of Ariana Dumbledore, for example, to epigenetics and her traumatic experience. In the case of Neville Longbottom, his family and their smothering influence made him into a late bloomer, magically speaking.

Between the relatable subject matter and approachable presentation, this was an excellent tangent look at a classic favorite.

Author of the article

JP Barnaby, an award-winning gay romance novelist, is the author of over two dozen books, including Aaron and Painting Fire on the Air. When she's not hanging out with porn stars or being spanked by hot guys in leather, she binge watches shows like Daredevil and Agents of Shield. A physics geek, she likes the science side of Sci-Fi, and wants to grow up to be Reed Richards.