Oh, Nephilimfree, you've done it again. You went and dragged genetics through the mud again, and I won't stand for it.
At this point, having dedicated a few posts to his inane ramblings, debunking Nephy's claims is beginning to feel like picking on the fat kid at the playground. He's a slow, lumbering target, and all the other kids on the playground keep picking on him because he's easy prey. But Nephy is so ripe with nonsense, so overflowing with vacuous crap like a bountiful cornucopia of bullshit, that it's hard to resist tearing his arguments apart when I'm looking for something to write about. And his silly website [Edit: 06/11/11: Looks like Nephy has let his registration of his domain lapse, so that link doesn't work any more. I tried to find an archived version, but had no luck] has no shortage of fodder for a creationist asskicking.
This week, I took a look at this article he wrote about the enzyme nylonase. You've probably heard about nylonase before, as it is often given as a great example of an evolutionary adaptation that has occurred in recent history. In 1975, a team of researchers from Osaka University in Japan got the idea to try and culture sludge obtained from the waste water outside of nylon factories1. The samples they collected were used as inocula, and added to cultures which contained a form of nylon (6-aminohexanoic acid cyclic dimer) as the sole carbon and nitrogen source. Any bacteria that grew would have to rely on metabolizing nylon to survive. And grow they did. They designated the strain as KI72, and after isolating the bacteria, they identified it as a strain of Achromobacter guttatus, although later work by the same team reclassified the species as a strain of Flavobacterium2. A few years later, the researchers identified two novel enzymes which allow the bacterium to metabolize nylon: 6-aminohexanoic acid cyclic dimer hydrolase and 6-aminohexanoixc linear oligomer hydrolase (6-AHA CDH and 6-AHA LOH, respectively)3,4. Since nylon production began in the 1930s, these enzymes had to have originated in the time since then. After all, it doesn't make much sense for a bacterium to have produced enzymes to specifically degrade nylon before nylon itself was invented. These genes, then, represent an example of a novel adaptation arising outside of the lab and within the past century.
But Nephy disagrees. He states,
Two paragraphs in, and he's already run into a major problem. He seems to have this odd idea that unless a change results in gross morphological alterations, it cannot be an evolutionary change. He simply discredits novel biochemical adaptation out of hand without any sort of justification. He simply wishes to define evolution as changes in "form and structure" and ONLY changes in "form and structure" - any other kind of change he refuses to acknowledge as evolutionary change. In essence, he's defining evolution in his own incredibly narrow terms, so that any actual evolutionary change can be shrugged off as "not evolution". If we were to narrowly define creationism as "the spontaneous formation of aardvarks from forest detritus", it would be pretty easy to discredit, too."Because the bacteria encountered nylon and developed an ability to digest it does not provide evidence of any kind of evolutionary change. This ability does not effect the form and structure (morphology) of the bacteria by introducing any new structural feature, nor does it transform any existing structural feature of the bacteria into a new kind of structure with a new physiological function."
But beyond that, it is simply silly to only accept large changes in morphology as the only kind of evolutionary change. Morphological alterations cannot occur all at once. Any modification to an organism's body plan would require many not-so-obvious biochemical changes to occur first - the very type of changes that Nephy does not accept as "evolution". Evolution can only work with what it has available. No organism is going to mutate and grow wings de novo all in one shot, even if it would be advantageous. Such changes would require modifying the existing body plan, and this would require extensive biochemical changes to happen first.
Nevertheless, the discovery of novel nylon-degrading enzymes is indisputable. Musing over the origins of these enzymes, Nephy declares that these proteins, or any protein, could not have simply evolved. No, he says, statistical analysis says otherwise:
"The field of sicence [sic] called Statistical Ananlysis [sic] which is employed to determine probability in various fields of science, has determined that the formation of proteins by random molecular interactions is on the order of 10^950, which is 1 to a number for which no name exists; a number greater than all of the paticles [sic] of matter in the speculated universe. In other words, according to science itself, the chance of a single, medium-sized protien [sic] arising by purely materialistic molecular interactions is considered impossible to science because it is considered impossible times impossible times impossible. The evolutionist would have you believe that random mutation is capable of producing novel protiens [sic] which have specific function, but this is not only unfounded but exceedingly irrational."
This is a typical creationist talking point: whipping out statistics to churn out large numbers and proclaim "See! It's statistically impossible for evolution to occur!" It is also typical, as Nephy demonstrates quite well, for creationists not to cite the source of these statistical calculations. The problem with Nephy's argument is that he does not take into account the process of selection during evolution. Forming a protein "randomly" and all at once is incredibly unlikely (though not entirely impossible), but if you factor selection into the equation, it becomes an incredibly likely phenomenon. Richard Dawkins illustrates this beautifully in his book The Blind Watchmaker, where he likens evolution to monkeys banging away at typewriters. If you were to wait for a monkey to type out the sentence "Methinks it is like a weasel", you'd be waiting for eons for it to "randomly" happen. But suppose you were to use cumulative selection to pick and keep the letters that work. Dawkins wrote a computer program to do just this (as computer programs are much cheaper and easier to work with than hordes of monkeys). Starting with a string of gibberish and then changing one letter per generation, the computer program "evolved" the correct sentence is about 40 generations5. It took only a few minutes for the computer program to complete this task, whereas single-step selection (waiting for the correct sentence to happen randomly, and all at once) would have taken the computer "a million million million million million years"6. Obviously, selection gets past the staggering statistical improbability that creationists argue.
But Nephy continues. He tells us that it was discovered that the nylonase genes originated from a frameshift mutation, resulting in an alternate reading frame which produced a novel enzyme7. This may be true, but recent work by Negoro et al indicates that the origin of the genes might be due to base substitutions after an ancestral gene duplication8. Nephy proceeds to tell us that there are only two ways that such a frameshift can occur: a random mutation or by a "Programmed Translational Frameshift Mutation".
At last, we come to the crux of Nehpy's argument. According to him, random frameshift mutations are invariably bad and the idea of a random frameshift mutation is a cop-out employed by "evolutionists" to ignore the reality of intelligent design. The origin of nylonase must be due to "Programmed Translational Frameshift Mutation", a process, he claims, is divinely inspired..
At this point I feel I should clear something up. Nephy, I hope you're reading. There is no such thing as "Programmed Translational Frameshift Mutation". Programmed Translational Frameshift (PTF) is a very real process, but it is not a mutation. PTF actually describes a variety of complex, but similar, processes. The essence of the idea is this: under normal circumstances, a protein is produced when a ribosome translates a strand of mRNA. Usually, the ribosome translates in a linear fashion, starting at the 5' end of the strand and reading the length of the strand until it comes to a stop codon at the 3' end. But in certain cases, the ribosome can be induced to "skip" or "hop" over a number of nucleotides in the sequence. The result is that the ribosome is shifted out of frame, and the resulting gene product is unlike the original9. With PTF, one gene sequence can produce multiple gene products: the original, unshifted, product and the second, shifted, gene product. This process is not a mutation. Mutations are changes to the genetic sequence itself, and such changes do not occur during PTF.
Perhaps Nephy's mistake stems from him being unable to comprehend the scientific literature. In his article, he describes PTF as "the modification of the arrangement of amino acids in a chain caused by information in the DNA which programs the event to occur", which is inaccurate, to say the least. This is further evidenced by the fact that he chooses to illustrate PTF with a diagram of alternative splicing, which is an entirely different process altogether! These errors would indicate that he simply did not understand what PTF is. I get the feeling that Nephy just skims through paper abstracts, pulling out words to form misshapen ideas, rather than taking the time to actually read any scientific papers.
But, regardless of whether or not PTF counts as mutation, Nephy's argument that nylonase originated due to PTF, rather than a simple frameshift mutation, doesn't hold much water. What we know about nylonase - the gene's sequence, how it is regulated, etc - would indicate that PTF is NOT at play here. As mentioned above, PTF occurs when a single transcript is read in two different reading frames, resulting in two different gene products. But in the case of nylonase, there is only ONE reading frame. It is always read by the ribosome in the same fashion. At no point is the ribosome prompted to switch to a new reading frame during translation - a hallmark of PTF. In many cases, this switch is induced by particular sequence elements, but the nylonase gene does not contain any such sequence elements. All evidence points to an ancestral gene that underwent a frameshift mutation that permanently altered it's reading frame, rather than two different and active reading frames from a single sequence. The original frameshift alteration was likely transcriptional in nature rather than translational.
Nephy's claim that random frameshift mutations are always harmful is nonsense as well. In any case where a mutation is deleterious, creationists are quick to say "See! Random mutations are bad!"; any case where a mutation proves to be beneficial, they shout "That didn't count! That was Intelligent Design!". This amounts to little more than special pleading. Nephy does not see it this way. He states
"The problem for evolutionists is that we have discovered that random frameshift mutations produce novel proteins which do not have a function in the cell, and when produced in great numbers, are causes of diseases such as Alzheimers and Tay-Sachs."
But how are deleterious mutations and non-functional proteins a problem for evolution? On the contrary, they are a huge problem for Creationists! After all, why would God allow for non-functional proteins to cause deadly conditions? Why would God allow for mutations to begin with? Pretty sloppy work for a Creator who is supposedly "perfect".
Another issue with his argument is how he ascribes PTF as an "intelligent design process". What evidence does he have that PTF is not a naturally occurring process? Why does he call it intelligent design? He gives no reason. He simply slaps the ID label on and announces "Hah! PTF proves intelligent design!" with no justification whatsoever. One could just as easily label espresso brewing "intelligent design" and proclaim that Starbucks baristas are evidence of divine creation. It is nonsensical.
Nephy proceeds with a few paragraphs of rambling spew about DNA being a "computer code". I have already talked at length about why DNA is not a code, so I will not go into it here. Needless to say, it makes little sense.
So what it all comes down to is this: the nylonase gene is a product of a frameshift mutation and not programmed translational frameshift; programmed translational frameshift is not a mutation, nor is it evidence of Intelligent Design; biochemical adaptations do count as evolution; and nylonase still illustrates a wonderful example of evolution occurring within recent memory. Once again, Nephilimfree abuses genetics to form a murky mire of distorted truth, and once again, his claims do not stand up to the scrutiny of critical thought.
1. Kinoshita, S.; Kageyama, S., Iba, K., Yamada, Y. and Okada, H. (1975). "Utilization of a cyclic dimer and linear oligomers of e-aminocaproic acid by Achromobacter guttatus". Agricultural & Biological Chemistry 39(6): 1219−23
2. Negoro, S.; Shinagawa, H.; Nakata, A.; Kinoshita, s.; Hatozaki, T. and Okada, H. (1980). "Plasmid control of 6-aminohexanoic acid cyclic dimer degradation enzymes of Flavobacterium sp. KI72". Journal of Bacteriology 43(1): 238-245
3. Kinoshita, S.; Negoro, S.; Murayama, M.; Bisaria, V. S.; Sawada, S. amd Okada, H. (1977). "6-aminohexanoic acid cyclic dimer hydrolase . A new cyclic amide hydrolase produced by Achronobacter guttatus KI72" European Journal of Biochemistry. 80: 489-495.
4. Kinoshita, S.; Terada, T.; Taniguchi, T.; Takene, Y.; Masuda, S.; Matsunaga, N. and Okada, H. (1981). "Purification and characterization of 6-aminohexanoic-acid-oligimer hydrolase of Flavobacterium sp. KI72". European Journal of Biochemistry. 116(3): 547-551
5. Dawkins, R. (1986). The Blind Watchmaker, p. 48
6. Ibid. p. 49
7. Ohno, S. (1984). "Birth of a unique enzyme from an alternate reading frame of the preexisted, internally repititious coding sequence". Proceedings of the National Academy of Sciences. 81: 2421-2425
8. Negoro, S.; Ohki, T.; Shibata, N.; Sasa, K.; Hayashi, H.; Nakano, H.; Yasuhira, K.; Kato, D; Takeo, M. and Higuchi, Y. (2007). "Nylon-oligomer degrading enzyme/substrate complex: catalytic mechanism of 6-aminohexanoate-dimer hydrolase". Journal of Molecular Biology. 370: 142-156
9. Farabaugh, P. (1996) "Programmed Translational Frameshifting". Microbiological Reviews. 60(1): 103-134