Letter • April, 2018

Reader provides clarification

I wish to clarify some matters arising in Ron Hodgson’s article “Dancing to the music of your DNA” in the February-March issue. He makes a factual error in calling mitochondrial DNA a “sex chromosome.” Mitochondria are autonomously reproducing objects within cells. Egg and sperm cells have mitochondria, but when a sperm cell fuses with an egg cell it leaves its mitochondria behind, so only the mother’s mitochondria are present in the fertilized cell. More broadly, he perpetuates the obsolete concept of DNA as the uniquely determinative “master molecule”. Hodgson quotes from Richard Dawkins’s book The Selfish Gene, which was written in 1976, before the Human Genome Project forced us to revise our understanding of the gene. In fact a living cell is a super-system of interlocked systems which regulate each other—all dancing to each other’s music, if you will. For further detail I recommend the Royal Institute lecture “What Is Epigenetics?” (YouTube) and the following books, all available at the Ottawa Public Library: The Century of the Gene, by Evelyn Fox Keller; The Tinkerer’s Accomplice: How Design Emerges From Life Itself, by J. Scott Turner; and (as e-book) Biology as Ideology: The Doctrine of DNA, by Richard Lewontin.

Frank Heilingbrunner

St. Andrew Street