In my blog post It’s Time to Tighten the Definition of “Random” I said it makes no sense to say “There is a pattern to a mutation’s randomness.” Joshua Swamidass (Washington University) and friends challenged me on this.
Before I respond, let’s understand why anyone should care.
I first tumbled into the evolution rabbit hole in an argument with my brother, a missionary-turned-nearly-atheist. “Bryan, look at the hand at the end of your arm. That is a nice piece of engineering! You don’t think it’s an accumulation of random accidents do you?”
Bryan shot back with the standard Neo-Darwinian salvo about random mutation and natural selection. This plunged me into a deep rabbit hole of research that still continues 14 years later.
In all my engineering experience, I had never seen anything evolve or even optimize through a combination of random copying errors and selection. Everything I had ever seen was the result of some intentional process.
I resolved to get to the bottom of this. Because if the biologists knew something the engineers didn’t, the engineers needed to get up to speed. Their careers would likely lurch forward if it’s possible to optimize incredibly sophisticated systems with random mutations and selection.
This also speaks to the question of whether evolution is random and purposeless, and whether science supports the meaningless, nihilistic view of the world that is typical of atheism.
What I discovered was that A) evolution is far more amazing than I had ever fathomed, and B) the mutations that confer antibiotic resistance, or symbiotic mergers, or generate new biological functions, are highly targeted genome edits that the cell executes in response to stress.
They are not accidental copying errors.
Joshua and friends replied that various kinds of randomness like white noise, pink noise, brown noise show distinct patterns even though the underlying signal itself is random.
I understand better now what they are saying and agree; I worked in the audio industry for three years. Yes, they are absolutely correct.
Yes, you can have a truly random signal that exhibits a pattern. Tune your car radio between stations and play with the bass and treble controls, and you can hear the patterns change.
White noise on your TV is about as close as you can get to true randomness. And if you change the color, it’s still random.
But all that misses the point of the original conversation.
“Last year I attended a lecture at Fermilab by Dr. Shapiro. After his talk, a group of people huddled around him in the cafeteria, peppering him with questions.
One guy suddenly ‘got’ what he’d been saying all night long. ‘You mean the mutations aren’t random?’ he asked.
‘No sir. They’re not random at all. “When bacteria are comfortable and well-fed, certain DNA changes occur at a frequency of less than one per billion cells.
But when they’re starving, the mutation rate skyrockets by a factor of 100,000. They develop new adaptations so they can survive.’”
Shapiro was discussing bacteria responding to stress, which he delineates in superb detail in his book “Evolution: A View from the 21st Century.” When I refer to “Evolutionary mutations” not being random, this is what I’m referring to.
I’m referring to transposable elements within the genome; epigenetic responses; somatic hypermutation to resist pathogens; and horizontal gene transfer, just to name a few mechanisms.
The opening chapters of his book detail the responses of yeast to stress and its use of Natural Genetic Engineering to alter its own genome. (By the way, this section of Shapiro’s book is not about population genetics.)
If you study these particular mutations in detail, mechanisms like transposition are not white noise, or brown noise, or pink noise, or any kind of noise at all.
They are very specific responses to very specific circumstances.
Joshua Swamidass insists these mutations were random.
Joshua, please define precisely what you mean by random. And then we can nail down whether they’re random or not.
This is a VERY important point. It’s prerequisite to any accurate understanding of evolution.