Noga Wies talks to us about Nonrandom.
Was there a particular discovery that was the turning point for you, the moment you decided to write a book about nonrandom mutations?
I was taught that mutations are random in high school, and I never really questioned that until I read about a fascinating subglacial lake in Antarctica. Back when Antarctica was part of a lush supercontinent near the equator, its lakes were “normal” lakes, inhabited by “normal” organisms. But about eighty million years ago Antarctica started drifting down towards the South Pole, where massive glaciers eventually covered its lakes. Amazingly, one of Antarctica’s subglacial lakes is still a liquid lake trapped under miles of ice. And as it turns out, it still contains plenty of unicellular organisms!
Subglacial life is no joke – “normal” organisms had to mutate to adapt to the darkness and the unbearably high pressure. Interestingly, many of them ended up with gene sequences that are identical to those of organisms from other extreme habitats, such as oceanic trenches. Let that sink in. The organisms in this lake have been completely isolated for millions of years, but they still acquired mutations that mirror those of organisms in similar, but faraway habitats. How, then, can we claim that mutations are random?
Why did the assumption that mutations are random become so entrenched in the first place?
The answer seems to be more political than scientific. As I explain in the book’s first chapter, the insistence on randomness stems from a desire to view neo-Darwinism as more “scientific” than Lamarckism, which is frequently misrepresented to serve this very purpose. To make things worse, Lamarckism has been unfairly linked to the policies of Lysenko, an agronomist who forced Soviet farmers to adopt pseudoscientific agricultural methods that led to severe famines. I leave it to the reader to decide if this is how a scientific consensus ought to be reached.
How can we be certain that mutations aren’t necessarily random?
We can look, for example, at the mutations that occur on dead genes. Dead genes, also known as pseudogenes, cannot produce functional proteins and are therefore ignored by natural selection. This means that their mutations “should” be completely random, because they cannot help or hinder survival in any way. But as I explain in the book, when the same gene “dies” in two completely different species, it is very likely to acquire the same mutations in both. Put simply, mutations are often stubbornly nonrandom.
Do nonrandom mutations pop up everywhere in the genome? Can we find them on sex chromosomes, for example?
Absolutely! Chromosomes come in pairs, and sex chromosomes make up just one of these pairs. Incredibly, Y chromosomes are constantly mutating into oblivion, which means that every so often, evolutionarily speaking, mutations must transform a pair of “regular” chromosomes into a pair of sex chromosomes. You’d think that chromosome pairs would be randomly selected for this transformation, but that’s just not how it works. Believe it or not, the same chromosome pairs are always tapped!
What's the question you're most curious to see answered in the next five or ten years?
This book describes how many different kinds of mutations are far from random on many different levels. But why? What are the mechanisms underlying this nonrandomness? I can’t wait to find out!
Order your copy of Nonrandom here.
