[00:00:04] Speaker A: ID the Future, a podcast about evolution and intelligent design.
[00:00:12] Speaker B: Welcome to ID the Future. I'm Eric Anderson. And joining us again today is Dr. Casey Luskin to discuss a brand new book he contributed to Science and Faith in Dialogue, part of the Reformed Theology in Africa series. Dr. Luskin is Associate Director at the center for Science and Culture at Discovery Institute. He holds a law degree from the University of San Diego, bachelor's and master's degrees in Earth sciences, and a PhD in geology from the University of Johannesburg. Thanks for being back with us, Casey.
[00:00:39] Speaker A: Thanks for having me, Eric.
[00:00:41] Speaker B: So last time we got into the details of the fossil record of hominins and we learned that the fossil record doesn't really support a transition from ape like creatures to humans. To summarize what you noted at the end of the discussion, we said, we've got ape like fossils, we have human like fossils, but not a good set of transitional fossils documenting how one group evolved into another. And that several researchers, as you read in your chapter, have acknowledged the genus Homo came about in an explosion or abrupt appearance or rapid increase in features. So today I want to discuss another claim about human evolution, the claim that humans and chimps share 98 or 99% of their DNA. You quoted science popularizer Bill Nye, who said, as our understanding of DNA has increased, we've come to understand that we share around 98.8% of our gene sequence with chimpanzees. This is striking evidence for chimps and chumps to have a common ancestor. So, Casey, is Bill Nye alone? How common is this claim about our common ancestry based on DNA?
[00:01:42] Speaker A: Oh, I think we've all heard this claim that we're only maybe 1 to 2% different genetically from a chimpanzee. And therefore this is evidence of our. Our close evolutionary relationship. It's almost ubiquitous. You can't go through the world today without hearing this argument.
[00:01:57] Speaker B: Yeah, and it's not just from folks like, you know, Bill Nye the Science Guy. I think you quoted the American Museum of Natural History and textbooks.
[00:02:05] Speaker A: You're going to get it from much more academic sources than Bill Nye the Science Guy, who I'm a fan of his old show, by the way, before he turned out to be a raving materialist. I really enjoyed his work.
[00:02:15] Speaker B: Absolutely. But you're less impressed with this DNA. Why this evidence for common ancestry, I should say.
[00:02:21] Speaker A: Yeah, well, we just now know that it's not true. I mean, there was an article that came out in the journal Science in 2007 that I think was really started to be the death KNELL of this 1 to 2% statistic that we're only 1 to 2% different from chimps. Now this should have been known earlier because the chimpanzee genome was first sequenced in 2005 and when that was published it became clear that this 1% difference from chimps, the situation was a lot more complicated than that. In fact, that 1% difference statistic is basically derived from a single protein protein comparison. But when you start to look at comparing entire genomes, you find out that we're far more different from chimpanzees. This article in the journal Science in 2007 was titled Relative the Myth of 1%. And it claimed that this idea that we're only 1% different from chimps is a truism that that should be retired. And it talked about, look, even if we do just look at the known genetic differences when chimps, and I think it's even more than what they reported in this, in this article that it entails 35 million single base pair genetic differences, 5 million indels that would be insertions or deletions of nucleotide bases that are of two or more base pairs in length and also 689 extra genes in human beings. And they said that when you look at just simple gene copy numbers, we're 6.4% different from chimps. So there's a lot more to talk about in this genetic comparison than mere, you know, comparing one protein to another. So over the last, you know, 10 or 15 years, there have been a number of scientists that have tried to do more rigorous studies of the actual genetic similarity or genetic differences between humans and chimps. Richard Buggs is a geneticist at Queen Mary University of London. And he looked at the exact one to one nucleotide matches between the human genome and the chimp genome, now that we have the chimp genome. And he found that you could only match them up 84.38% of the time. So that means that we're somewhere around, you know, 16% genetically different from chimps by that way of measuring it. Another study published in Frontiers in genetics in 2020 used a different method of comparing human and chimp genetic similarities. They looked at more DNA. They excluded, however, a centromeric DNA, but they did look at both coding and non coding DNA. And this paper found that we're about 96% similar to chimps, although that number could drop to as low as 93% if you consider centromeric DNA. Another biologist named Steve Schaffner estimated Human chimp genetic similarity at 95%. And so we got these estimates ranging from about 84% up to 96%. So what is the exact right way to do the analysis? Well, that's the big question. I don't think that anybody really has answered that question yet satisfactorily. One obstacle, by the way, to any of these analyses is that all of the chimp genomes that we have today were effectively humanized. This was admitted by the NCBI that essentially that the human genome was used as a scaffolding during the construction of these chimp genomes, which essentially makes the chimp genome sequences appear more similar to humans than they truly are. So I think until we get a chimp genome that has been constructed on its own without using the human genome as a scaffolding, we're going to artificially inflate that degree of similarity and we have to use a healthy dose of skepticism in any of these statistics.
[00:05:46] Speaker B: Yeah, so let me share one of my pet peeves. So we use this word similar. Chimps and humans, 99, 98% similar, whatever the term is that's thrown around. And, and I think that most people, certainly the public that's listening to this, understand that to mean identical. And so, you know, envision that you've got a string of a hundred characters and one of those is different. And so that would be 99% identical. But that's not necessarily how this term similar is even being utilized as they, you know, come up with this 99% similarity, is it?
[00:06:23] Speaker A: Well, it also depends on what you're comparing. Are you comparing the number of genes or copies of genes that the organism has? Are you comparing one to one nucleotide similarities? Are you including just the protein coding DNA or also the non coding DNA? Are you looking at certain segments of the genome that aren't even necessarily places where the sequence matters, like say the centromeres, or places where it's being used for more structural functions function rather than nucleotide sequence function. So there's a lot of questions to ask here. And depending on how you do the comparison, the differences can be very small or very big.
[00:07:01] Speaker B: Right, right. Talk to us for a minute about the idea of pseudogenes, because that was also used as a big push for proving, if you will, that humans and chimps are a common ancestor.
[00:07:11] Speaker A: Yeah, I don't think I get into this very much in my chapter, but pseudogenes are basically genes which are thought to have once been functional, but they have accrued mutations that have now rendered them Non functional. So, for example, you might have a gene that codes for some protein, but then there is a mutation that introduces what we might call a premature stop codon, where suddenly that protein is no longer able to be translated because it's no longer being fed through the ribosome in a way where it can be fully translated into the functional protein. And so these pseudogenes are said to be examples of, or sort of very strong, powerful evidence, even proof that humans share a common ancestor with chimps, because we'll find examples where chimpanzees have the same pseudogene in the same place that human beings do. And this is then said to can only be explained as the result of sort of genetic copying errors that were inherited by both chimpanzees and human beings from a common ancestor that had this mutation. The problem is that we now know that there are many examples of pseudogenes that have function and that even though sometimes we think that this is simply a gene where a mutation caused it to no longer be able to be translated or transcribed into RNA or translated into a functional protein, we now know that pseudogenes can have function even if they are not translated into a protein or even if they're not transcribed into rna. And so, for example, the RNA of a gene, the RNA of a pseudogene can be used to regulate the protein coding version of a gene and actually be involved in regulating the actual transcription translation of that gene. So they can have very important regulatory functions. And so we've seen some really interesting examples over the years, Eric, of evolutionary biologists using pseudogenes as sort of like case closed or silver bullet arguments for human ape common ancestry, only to then later discover that, that these pseudogenes actually have function. They are not simply shared junk DNA. We're talking about a junk DNA argument here. I should have said that at the beginning. They are not necessarily junk DNA. They can have function. And if they have function, then they might be there for a purpose. We might share these pseudogenes with other species for functional reasons, for a purpose, not simply because we inherited them from a common ancestor. My favorite example of this is, there's a lot of examples, but my favorite example of this is, is the beta globin pseudogene. Back at the Dover trial, Ken Miller argued that the beta globin pseudogene has shared molecular errors in human beings and in gorillas and in other apes. And this is evidence that we share a common ancestor. So this was said to be very powerful evidence for common ancestry. Well, lo and behold, There was a paper that was published in 2013 that found that these beta globin pseudogenes are more similar to the protein coding versions of the genes than they should be if they were just non functional junk that were accumulating random mutations over time. Then about a year and a half ago, in late 2021, Eric, there was a lecture that was posted by Eugenie Scott, the famous evolution advocate, at the American Museum of Natural History's YouTube channel. And this is from back in 2007 where she also was using Ken Miller's argument saying, oh well, the beta globin pseudogene is a great example of where ID theorists and the creationists, as she always says, get it wrong. And clearly this is an example of shared molecular errors, blah, blah, blah, blah. So in the very end of 2021, I decided to go back to the literature and see, well, what else has been published over the last few years on this beta globin pseudogene. Has anything else been published? And I discovered that indeed there was a paper published in February of 2021 that found that the beta globin pseudogene is actually essential, this paper said, for producing red blood cells in human beings. Eric, so what? What Eugenie Scott and Ken Miller claimed was junk DNA and evidence of our shared molecular errors with gorillas. Ken Miller telling Judge Jones in the Dover trial that this is powerful evidence of our common ancestry with apes because of this quote unquote non functional DNA. That non functional DNA has later turned out to be essential for producing red blood cells. So I think this is a great example of how the junk DNA argument is not a safe or smart argument to make. You're very likely to be proven wrong. As the march of science goes on and we learn what this quote unquote junk DNA is actually doing.
[00:11:38] Speaker B: Yeah, that's a great example. I love that. Yeah. And so all of these just for our listeners. Again. So junk DNA includes both, or the idea of junk DNA. Let me say it that way. The idea of junk DNA includes both non coding DNA, pseudogenes, retroviruses, all these things that were thought to be just the flotsam and jetsam of the evolutionary process. And one by one, many of these things are turning out to be functional. If you are a junk DNA proponent, you are making an argument for ignorance. Let's make that point first of all, and second of all, you are standing on the wrong side of the trajectory of the evidence because we can't unlearn once we find something has a function, we can't unlearn that. But we can certainly, and we do regularly learn that things that we didn't know what they did have functions. So that's, I agree with you. It's a very dangerous side of the line to be standing on. If you're pointing to something, you don't know what it does, and you say, well, that must be junk.
[00:12:26] Speaker A: Yeah, great, great point there, Eric. The trend line of the evidence shows that we're consistently finding more and more evidence of function in junk DNA.
[00:12:35] Speaker B: So let me play devil's advocate for just a minute. Let's go back to this percentage similarity, identity, whatever you want to call it, however we measure it, let's assume that humans and chimps, in fact have 98 or 99% similar DNA by some measurement. So what, what does that tell us about us and chimps?
[00:12:49] Speaker A: Yeah, I think that's the exact question. Your percent DNA similarity between two species really does not tell you anything about whether or not they are genetically related. In fact, you know, we're, we're 25% or actually, I'm sorry, I think it said that we're 50% similar to a banana, genetically speaking. So. But you'll still see evolutionary biologists claiming that we are related to bananas. Right? That's, that's no joke. And at what point does this actually become sort of a rigorous, falsifiable argument? You know, when the percent similarity drops below X percent, are we no longer related? No, there is no way to falsify this argument. According to evolutionary biologists, everything is related, regardless of whether they have a high or a very low degree of genetic similarity. So we have to start asking the question, are there other potential ways to understand genetic similarity outside of sort of the standard evolutionary paradigm? And I would say yes. I think that when we're talking about functional genetic similarity, that common design can explain many of these similar genomic sequences, where organisms are designed and built upon similar blueprints. And they have to have similar functional genetic components for functional reasons. So when you see that two organisms have similar morphologies or, you know, body structures or lifestyles, you would expect that they're going to have similar genetics. I mean, humans and apes, we all walk on the ground, we all breathe air, we all need to be able to see light with our eyes. We all have brains and hearts that pump blood through our bodies and brains that we think with. So it's no wonder that we have similar genetics when we have such similar body structures. I like to say that if something is similar above the hood, there's A good chance it's also going to be similar under the hood. And this is certainly true with genetics. So the fact that we share similar DNA structures and have a high genetic similarity to chimpanzees, I think that's to be expected given that we know that we have similar morphologies. But those similarities could be reflecting comma design, where we've been built based upon a common blueprint. Comma design is actually a good engineering principle to use, where engineers will frequently reuse parts or components that work in different designs, different technologies. So, for example, we will see wheels being reused on both cars and airplanes, or we'll see keyboards being used on both laptops and cell phones. And so we will see engineers will reuse parts that work in different contexts. The same is done in computer program. If you want to get into the software world. Software engineers will constantly reuse coding modules in new programs that do things that they need them to do. So that might be exactly what we're seeing in living organisms, where these genetic similarities simply reflect common design to meet common functional requirements, using common coding modules in the genome and building things based upon common blueprints. Another important point on human chimp genetic similarity, Eric, as my colleague Ann Gager likes to say, is that it's the differences that sometimes matter more than the similarities. And so even if we only have, say, 1, 2, 3, 4, 5, 6, 10% different, genetically speaking, between humans and chimps, those can encode huge amounts of differences that will play into our morphology. The way our proteins are transcribed and translated, the way our bodies are formed, what goes on in our minds. So even a few percent genetic difference can yield huge changes to two different organisms. So I would say that, you know, even if we are very similar, genetically speaking, don't think that that means that we're just like a chimp. Those differences can make huge differences.
[00:16:20] Speaker B: Well, that's a really good point. And you use an example in your chapter of somebody building a building with materials, right? You go to the Home Depot or wherever you get your building materials from, it's all the same materials. But that doesn't mean that everybody who walks out is going to build the same exact thing with it.
[00:16:36] Speaker A: Exactly. When you want to build a house, you're going to buy wood, you're going to buy brick, you're going to buy nails, you're going to buy screws, and that's just what you make a building out of. But that building plan, the blueprint, is what decides where all the parts go. And those few percent differences between Humans and chimps might be describing blueprint differences that ultimately yield huge differences in what we are and the way we live and how we operate as organisms. So, yeah, look at those differences and pay attention to those.
[00:17:05] Speaker B: Yeah, that's a great point. So there's this sense that, because we hear this all the time, Casey, that humans and chimps are so similar. And you've addressed how that might be a common design pattern as well. But now let's shift a little bit, because once you start looking at the details, there's a lot of differences in behavior, intelligence, development, even the morphology. I think there's more than a. Somebody mentioned there was more than a hundred physical differences between humans and chimps just at the gross morphological level. Never mind what's under the hood in terms of the genetics. So you write in the chapter, there's a vast cognitive and behavioral gulf between the species. What do you mean by that?
[00:17:45] Speaker A: Yeah, I mean, obviously chimpanzees and actually all animals don't use language, complex language and symbolic thought in the way that human beings do. And so there's no question that there is a huge cognitive gulf. I mean, we're the ones that write scientific papers about chimpanzees, not the other way around. We're the ones that compose music, that create art, that build cathedrals, that use complex technology, that create religion and write symphonies. So I think that there is just an undeniable cognitive gulf between humans and our supposed closest relative, the chimpanzee, in terms of what we can do with our minds.
[00:18:25] Speaker B: Yeah, and there's another sort of basic, what do I call it, theoretical issue here when we talk about similarities. You know, Darwin didn't write a book called How Organisms Retain Their Similarities Over Time. He's trying to explain, he thought he was explaining. And what needs to be explained if we're going to take evolution seriously is the differences. And so we have this vast cognitive and behavioral gulf, as you call it. There's differences in morphology and intelligence, development and behavior.
Some have proposed that, hey, we can kind of get this through just a couple of coordinated mutations or maybe one mutation at a time. Tell us a little bit about the Durrett and schmidt paper from 2008.
[00:19:06] Speaker A: Excuse me, Durrett and Schmidt. There are two mathematicians, I believe, at Cornell who tried to refute some of Michael Behe's arguments that if you require multiple mutations before you get some evolutionary advantage, that this causes a problem for Darwinian evolution. And so Behe had argued that, and they set out to refute him. They certainly quibbled with some of his specific mathematical conclusions. But what they ended up doing, in my opinion, and I think the opinion of other folks in the ID community, is they actually end up really validating what Behe was arguing. Because they found that if you have a trait that requires two or more mutations in a population, such as human beings or hominids, where they tend to have long generation times and low population sizes, so not a lot of trials, not a lot of opportunities to get these mutations that you need. So if you just have a relatively simple trait where two or more mutations are needed before you get some evolutionary advantage, they found that such a trait would take over 200 million years to arise in a population such as human beings. Now, if you only need one mutation before you get an advantage, then natural selection, random mutation, can probably do the job. But as soon as you require multiple mutations, then suddenly the probabilistic resources that you need start to go up exponentially. And it goes to a point where, in their own words, it's not a reasonable time scale to produce such a complex feature. So the Dirt and Schmidt paper basically said that if you've got a trait that requires multiple mutations to give a advantage, it is not going to rise. Certainly not since we shared a common ancestor with apes, which would have been only, you know, maybe say, 6 to 8 million years ago. So what we see in the field of evolutionary psychology and cognitive evolution is what I call sometimes they will put forth these miracle mutation stories of the origin of human cognition, where they will say, well, you could only maybe require one mutation to suddenly evolve human like cognition from apes. Well, I'm sorry, but that's just impossible. I mean, it's not like apes are just one mutation away from becoming as intelligent as human beings. Undoubtedly, multiple mutations in multiple genes would be necessary to account for the origin of things like human language or human complex abstract thought and all these different cognitive abilities that we have. So if multiple mutations would be necessary before you get some advantage along the supposed evolutionary pathway, then there's no way that that could arise in the mere 6 to 8 million years since we shared a common ancestor with chimpanzees. In fact, if you go back to that paper I mentioned earlier, Eric, in the journal Science, that paper called the myth of 1%. Basically, that paper said that we have 35 million individual base pair differences between human beings and chimpanzees. Okay? So if you look at all those 35 million base pairs, if there's only one case where you required two mutations before you got an advantage in the evolutionary lineage that led to humans, then that trait could not evolve in the amount of time allowed by the fossil record. Since we supposedly shared a common ancestor with chimpanzees, we're literally looking at a mathematical refutation of an unguided neo Darwinian origin of human beings. It could not happen in the time allowed. So I think this is very interesting and very compelling to think about.
[00:22:27] Speaker B: Yeah, yeah. And I want to give a shout out to David Snoke as well, who I think was involved with Mike Behe's original paper.
[00:22:34] Speaker A: Yes, that's right. David Snow, Behe and Snoke wrote a paper in the journal Protein Science, and then Dirt and Schmidt tried to refute that in the journal Genetics. And so it's a great scientific dialogue. They did quibble with the math, but in the end, it's one of those times where we'd be happy to be proven wrong like this, where it ends up validating the ID arguments.
[00:22:53] Speaker B: Right, right. So later on the next year, I think in light of these unflattering results that their calculations produced for the evolutionary story, they tried to argue that maybe we don't really need too specific coordinated mutations. And here's what they said. There are at least 20,000 genes in the human genome, and for each gene, tens, if not hundreds of pairs of mutations that can occur. In the case in which the first mutant is neutral or mildly deleterious, double mutations can easily have caused a large number of changes in the human genome since our divergence from chimpanzees. Now, I want to ask you what you make of this, but to me, it's not completely clear what their argument is, but it seems to be falling back on the old claim that kind of anything goes, it's easy to get mutations. We don't have to have specific mutations to turn one organism into a human. Or maybe there were some required. But hey, it just happened to be the way it turned out. Right. Any number of things could have occurred. Humans happened to have resulted. There it is. And that kind of just sweeps the problem under the rug. But you've pointed that there are lots of things between humans and chimps that likely would require numerous mutations, certainly more than two.
[00:24:05] Speaker A: Yeah, I mean, they're definitely appealing to the unknowns and the undiscovered facts of biology there, where, oh, well, there's a million ways to do things so we don't have to worry about the numbers, essentially. I think the problem, Eric, is that when you look at biology, you find this phenomenon of convergence everywhere. Convergence is when you find the same traits, the same features appearing over and over again across different organisms, even widely unrelated organisms. This is very interesting. What this tells us is that in biology, there's not an infinite number of ways to do things. There's a limited number of ways to do things. And so that means that, okay, maybe it is necessary that you have to tweak certain genes in certain ways. Maybe it's the case that, you know, you can't just do it. Anything go. Anything doesn't just go. And so I think that the phenomenon of convergence really refutes their argument. When we look at the biology and the realm of biology, and we find that we see the same patterns and features appearing over and over again, it doesn't seem like there are infinite ways to do things, that there's only certain ways that. That biological systems want to work and work well.
[00:25:11] Speaker B: Yeah. And in addition to convergence, I think if you just look at systems, generally any complex system, there may be several ways that you can solve a particular problem. But we can put big numbers on it. Casey. We could say, let's say instead of one way to solve a problem, let's say there's 100. Heck, let's say there's a million ways to solve it. Once you start applying that into the math and the number of ways that the mutations could occur, you're. It's still a rounding error, and you're still in a situation where there's vastly, vastly more ways that something can get broken, not work, not happen, than the number of ways that it could work. And I think also thirdly, if you look at known cases where a single mutation can cause very serious diseases. Now, that doesn't always happen, but there are lots and lots of cases where a single mutation can cause serious problems. You really have to come away and say, is it realistic to believe that there's just this unlimited number of ways to get something done? It doesn't really matter which mutations it is. We kind of just, you know, go for it.
[00:26:09] Speaker A: Yeah, I. Exactly, Eric. I think that when you look, if there. Even if there were many ways to do this, you're still going to be in the same order of magnitude. You might be able to reduce the probabilistic resources you need by a little bit, but you're still going to be in the same ballpark of, you know, tens and tens of millions of years to get these complex mutations.
[00:26:28] Speaker B: Yeah. Yeah. So, Casey, what's the final takeaway from comparing human and chimp DNA in this claim that we often hear?
[00:26:35] Speaker A: I Think the final takeaway is that, yes, we are genetically similar to chimps to some degree. It's not known exactly what, but whether it turns out to be 84, which I think is about the current lower estimate, 84% to 96%, whatever the actual number turns out to be, it doesn't matter. As far as human chimp, common ancestry, whatever the number is, genetic similarities could reflect common design just as much as they reflect common descent. And so I think that the percent genetic similarity is, is simply not a good argument for common ancestry and it's not addressing these sorts of evolutionary questions.
[00:27:09] Speaker B: Yeah. And then once you layer on top of that the waiting time problem, which we didn't call it that, but that's what it's called, the waiting time problem that Behe and Snoke talked about, that others have worked on. I know Ann Gager and Ola, I think Hofstrayer.
[00:27:22] Speaker A: Yeah.
[00:27:22] Speaker B: And Guntrich Bakley worked on. Yeah. Also a recent paper from them. Once you address this waiting time problem and layer that on the top, I mean, the math just doesn't work. And I agree with you, this is really close. And I know the scientists involved would probably take a slightly more careful statement than this, but in my view, the waiting times issue is really close to a formal disproof of the Darwinian claim.
[00:27:46] Speaker A: Exactly. What you can say is that even if we did share a common ancestor with chimpanzees and other apes, that common ancestry did not proceed through standard unguided evolutionary mechanisms. Okay. That unguided aspect of the evolutionary story, I believe, is refuted by the Waiting Times Project and the Waiting Times arguments, as you said so. But I think that then puts other things on the table. Once you've said, okay, it was not an unguided evolutionary scheme, then what are other options that remain? Well, we can now look at the data and ask, well, maybe there's a reason why we see the abrupt appearance of human beings in the fossil record. Maybe there's a reason why we have this vast cognitive gulf between human beings and chimpanzees. Maybe we can understand our genetic similarities to chimpanzees in a totally different light. And so I think that, yes, that opens up new ways of thinking about things. Once you, once you realize that an unguided evolutionary story is not going to work.
[00:28:42] Speaker B: Well said. Well, Casey, thanks so much for being with us today to help us understand more about our human origins and this common claim that we hear that DNA similarity with chimps improves our common descent. I really appreciate you helping us break down the issues and do a little bit of myth busting, so to speak.
[00:28:57] Speaker A: Thanks a lot Eric. It was fun.
[00:28:59] Speaker B: Thank you for listening to this episode of ID the Future. To learn more about our human origins, as well as other topics like fine tuning, the origin of life, foresight in nature, and engineering principles applicable to biology, check out the new book Science and Faith in Dialogue, available as a free PDF download at discovery.org b discovery.org be join us again soon at ID the future and help us share these important messages by sharing a link with a friend. For ID the Future, I'm Eric Anderson. Thanks for listening.
[00:29:32] Speaker A: Visit
[email protected] and intelligentdesign.org this program is copyright Discovery Institute and recorded by its center for Science and Culture.
