PhD in Evolutionary Biology Says DNA Replication Points to Design ft. Dr. Jonathan McLatchie

Allan CP (: 00:00

Dr. Jonathan McLatchie, thank you so much for joining us today. One of the things that I love to ask is, of course, because so many people that are going to be listening to our students is, how did you get interested in not only intelligent design, but biology as a whole?

Dr. Jonathan McLatchie (: 00:02

Thanks for having me. It's great to be here. Sure, so I did my undergrad degree in forensic biology at the University of Strathclyde in Glasgow, Scotland. And during my undergraduate years, I became very fascinated with the complexity and designoid characteristics of living organisms. I was blown away by the engineering prowess and elegance of cellular machines and was often bewildered at the fact that someone could go through a four-year university program in the natural sciences and come out an atheist at the other end, because the evidence seems to be so compelling for the truth of theism, both in the life sciences, which is my expertise, as well as in the physical sciences as well.

Then subsequently I pursued a master's degree in evolutionary biology and another master's degree in medical molecular biology. These were from the University of Glasgow and University of Newcastle respectively. Then I did my PhD at the University of Newcastle in cell biology with a focus on the eukaryotic cell division apparatus by which cells divide—eukaryotic cells, being cells with a nucleus like our own. So yeah, I've been fascinated for many years in particular by the case for intelligent design, which I take to be very, very strong indeed.

Allan CP (: 01:32

With the topic of The Science Dilemma, we constantly want to point to how science points to intelligent design. So that being one of our goals, as a biologist, what's one big way that you think science points to intelligent design?

Dr. Jonathan McLatchie (: 01:47

Sure. We've discovered that the cell is full of digitally encoded information content that runs along the sugar phosphate backbone—or the spine—of the DNA molecule. This forms what we call the genetic code of life, where you have a language convention. In the language of DNA, you have triplets of nucleotides or letters that form words we refer to as codons. There are 64 different codons, and these specify amino acids. There’s redundancy—more codons than amino acids—so many amino acids are specified by more than one codon.

The sequential arrangement of these letters and codons determines the sequence of amino acids that form proteins. Then the way those amino acids are arranged determines how a protein collapses into its three-dimensional structure, based on the properties of the side chains of those amino acids. In every other realm of experience, when we find language conventions and information processing, storage, and retrieval apparatus, we habitually associate that with conscious activity or intelligent deliberative agency. So when we find information-rich structures, language conventions, information processing systems, and so forth, I think the best explanation is that they too arose by virtue of an intelligent cause rather than an unguided process of natural selection and genetic variation.

Allan CP (: 03:41

Yeah, basically, anytime that we see— I mean, is that kind of similar to the concept of like, if you put a thousand monkeys in a room, they're not going to write Shakespeare? I think that we've heard that before or something like that.

Dr. Jonathan McLatchie (: 03:53

Yeah, so there's a large element of chance that is necessary for the evolutionary process to work. Of course, evolutionists will say that evolution is not entirely a chance-based process, right? There's also natural selection, which is a non-random component. But chance genetic variations—mutations in the DNA—are sifted by natural selection. And natural selection is great at ensuring the survival of the fittest, but it's not so great at ensuring the arrival of the fittest.

It turns out that there are many systems throughout life which exhibit a property we call irreducible complexity. That is to say, you have various well-matched interacting parts that contribute to an overall function, where the removal of any one part causes the system to cease functioning. So this is not only a challenge to evolutionary processes—how would a blind search put together such a system one small step at a time when all the parts are needed for it to work—but it also points to design. Only intelligent causes are able to visualize a complex end goal and bring together everything needed to realize it. Unguided processes can't. If these systems are not particularly surprising on the supposition of design, but wildly surprising if design is false, then we’re justified in inferring design. These are, in my opinion, cumulatively overwhelming pieces of evidence for a design-based perspective.

Allan CP (: 05:49

Could you explain how irreducible complexity plays out in biology, from your expertise?

Dr. Jonathan McLatchie (: 05:58

Sure. There are many systems throughout biology—many thousands in fact—and it's best illustrated by examples. I think you've had Behe on in the past, and he likes to give the example of the mousetrap: if you remove the spring, the hold-down bar, the platform, or the staples, then it doesn’t work. It doesn’t catch half as many mice—it catches none.

A biological example is DNA replication. DNA replication prepares the cell for division by duplicating the DNA molecule, which stores the cell's information. This requires several well-matched, interacting parts. You have initiation proteins that open the DNA double helix. Helicase breaks the hydrogen bonds between the strands. Single-stranded binding proteins prevent re-annealing. Polymerase does the actual copying and must be clamped to the DNA by a sliding clamp, which itself is loaded by a clamp loader.

You need topoisomerases to relieve torsion stress—think of a phone cord coiling—and primase to synthesize RNA primers, since DNA polymerase can't begin without a 3' hydroxyl group. Because DNA strands are anti-parallel, the lagging strand is copied in fragments—Okazaki fragments—started by primase. Those RNA primers are later removed and replaced with DNA, and the fragments stitched together by ligase.

If any of those components are missing, the system doesn’t work at all. It’s broken. Getting even one of these proteins by mutation and selection is astronomically improbable, much less an entire coordinated system. Doug Axe’s work suggests the likelihood of getting a single stable, functional protein is about 1 in 10^77. And with systems needing multiple proteins that work together, those probabilities multiply.

Moreover, DNA replication is needed for natural selection to even operate—you can’t invoke selection to explain the origin of the replication system without assuming the very thing you're trying to explain. Unlike systems like the bacterial flagellum, where you might propose borrowing parts from other systems, DNA replication is so primitive that there’s nothing to borrow from. It’s a formidable example of irreducible complexity.

Allan CP (: 13:09

So if someone tried to push back on intelligent design here, it would be extremely difficult because you need all the parts for the system to function.

Dr. Jonathan McLatchie (: 13:22

Exactly. And remarkably, it's been shown in the literature that the enzymes used in DNA replication differ between the evolutionary lines of eukaryotes and archaea versus bacteria—they're not homologous. It looks like DNA replication arose independently at least twice, which exacerbates the problem. That strongly points to design as the better explanation.

Allan CP (: 14:03

Yeah, because the information already existed and it happened simultaneously or just in the past.

Dr. Jonathan McLatchie (: 14:09

I mean, it's enormously unlikely that it could happen once, but for it to happen twice independently with the same logic—that strains credulity unless there is a mind behind it.

Allan CP (: 14:22

Yeah, it’s two miracles happening that weren’t anticipated. So what does all this mean for intelligent design? What are we supposed to take away from this when we look at DNA replication?

Dr. Jonathan McLatchie (: 14:34

Intelligent causes, as I said earlier, have the unique ability to visualize complex higher-level objectives and gather everything needed to realize those goals. So on the supposition that a mind was involved, these systems aren’t particularly implausible. I don’t have to say they’re highly probable—just that they’re not highly implausible. But on the falsity of design, they’re very implausible. That top-heavy likelihood ratio favors design. This is a Bayesian inference.

As you examine more examples—other complex systems, causal circularity, rarity of protein folds—it all points strongly to design being the best, most elegant, most probable explanation.

Allan CP (: 15:34

So understanding that about intelligent design and the implications of DNA replication, I also want to pivot. You’re not just a scientist, you’re also a writer, a debater, and a professor. Why does the topic of intelligent design matter for the everyday person or family?

Dr. Jonathan McLatchie (: 16:02

Intelligent design is part of a broader cumulative case for a creator behind life and the universe. There’s evidence for design in both life and physical sciences. The universe seems to have had a beginning, dated to about 13.8 billion years ago. There’s remarkable fine-tuning in the laws and constants of nature. There's also the argument from the environmental fitness of nature—features of the periodic table, light, water—that make life possible, particularly advanced life.

Then there’s the design evident in biology. All these features are not very surprising if a creator exists, but they’re wildly improbable otherwise. And having a creator is consistent with Christian theism. I’m a Christian, and I believe there’s formidable evidence not only for general theism but for Christianity specifically. If anyone is struggling with doubts, I run a ministry called TalkAboutDoubts.com where people can connect with experts in science, philosophy, biblical archaeology, and more via private Zoom meetings.

Allan CP (: 18:18

I love that. I think so many people—even if they aren’t Christians—would benefit from hearing from experts. That’s awesome. Other than Talk About Doubts, is there anywhere else people can follow your work?

Dr. Jonathan McLatchie (: 18:46

Yes, I have a website at jonathanmclatchie.com which hosts a lot of my writing in both science and New Testament studies. I’m also a frequent contributor to evolutionnews.org, and we have a podcast at idthefuture.com. Discovery.org/ID is our main hub for the Center for Science and Culture at Discovery Institute.

As for books, I’d start with Undeniable by Doug Axe and Darwin Devolves by Michael Behe. Both write very accessibly for a general reader.

Allan CP (: 19:41

Awesome. I feel like if anyone wanted to cover all the topics you work on, it would take years of podcast episodes. I appreciate you so much.

Dr. Jonathan McLatchie (: 19:49

Yeah. Thanks so much for having me. Have a good one.