DNA’s story rife with contradictions, mutations

Hey there, time traveller!
This article was published 27/08/2016 (3630 days ago), so information in it may no longer be current.

Genetics is a young and modern science, and one of the most potent in its capacity to help us understand ourselves, but also to make us uncomfortable.

Just as he did with his “biography” of cancer in the Pulitzer Prize-winning The Emperor of All Maladies, Siddhartha Mukherjee has written an “intimate history” of the gene. In his own words, this is a prequel — whereas cancer is a disease of genes gone badly wrong, genes themselves are essential to what we consider normal and healthy life.

While the history of the gene itself stretches back billions of years, the history in this book begins in 1865, because it is really the human story of the discovery, understanding and, finally, exploitation of the gene.

The first personalities are a barnacle enthusiast named Charles Darwin and an underachieving monk, Gregor Mendel. Darwin knew his theory of evolution by natural selection was incomplete because he didn’t understand how heredity worked, while Mendel’s garden experiments, identifying dominant and recessive traits in plants, cast light on exactly that. Unfortunately, they never met, and their ideas didn’t cross-pollinate for several decades.

The greater part of the story comes from the 20th century, when scientists first learned genes lived in DNA, identified the structure of the DNA molecule and then learned to read its code. As a punctuation mark on the century, the Human Genome Project announced its complete sequence in the year 2000.

Like The Emperor of All Maladies, this book is divided into six roughly chronological parts. Mukherjee’s story eventually reaches the present, and finally peers into the future, as the ability to read and manipulate genes gives us insight into long-standing questions about ourselves.

The answers are rarely simple, but rife with seeming contradiction. Biological gender at one level is indeed binary, but at the same time is subject to varying degrees and malleability. And studies show gay men were indeed born that way, and yet an identical twin, with identical genes, may be straight. In almost every direction, individual identity has both genetic and environmental roots.

The contradictions in genetics are one of Mukherjee’s recurring themes, and they reach deeper, to the molecule of DNA itself. It is the carrier of our genes precisely because it can create faithful copies of itself and carry its message across eons. However, all of life’s endless forms most beautiful are only possible because those copies are not entirely faithful, and the message is modified with every generation.

Although most of the history has been told before, there are a few reasons Mukherjee’s book stands out. For one, he’s a sharp writer and an engaging storyteller. Interspersed with the famous scientists are excerpts from his own family history, to illustrate the intimate role genes play in all our lives.

In the case of his family, it is mental illness — schizophrenia and bipolar disease — that have wreaked havoc. These illnesses have a genetic component, but there are other components as well. As a Mukherjee, how worried should he be for his own sanity?

Between the lines lurks another question: If it were possible to scrub out mental illness from the human germline, what else would we lose? Mukherjee is a Rhodes Scholar, a professor, a medical doctor and a Pulitzer-winning author. Perhaps such an exceptional mind is more likely to arise from the same genetic dice rolls that gave his cousin and uncles their afflictions.

The titular figure in The Gene may be essential to life, but it is not the entirety of life. As new technology expands our ability not only to read our genetic code, but also to cut and paste and edit, the opportunities and the dangers are very real, but they are tempered by the fact that the environment, the individual’s story, is also central in forming a life.

Paul Klassen is a Winnipeg engineer, professionally involved with dihydrogen monoxide rather than deoxyribonucleic acid.