Wednesday, April 2, 2014

The Making of a Paradigm Shift: It's All Over

The final video in this series is about a human trait called "lactase persistance", the ability to digest lactose, the main sugar in milk, throughout adulthood.

Opponents of intelligent design often accuse the theory of not making any predictions. Well, I have made all sorts of predictions in this series. One prediction I made was that virtually all evolutionary adaptations can be explained by broken genetic mechanisms, or previously broken mechanisms that get fixed by interbreeding. I know a whole lot more about the lac operon in E. coli than I do about the lactase gene in humans, but I'm willing to predict that lactase persistance involves a broken gene. Even before I watched the video, if someone had told me that human beings have a trait until they are adults and then lose it, but sometimes they don't lose it, I would have told you it probably involves a broken repressor function. (At this point the definition of "gene" gets a little hazy, since it includes both protein-coding and non-protein coding components, called "switches" in the video.) The evidence in the video in addition to intelligent design theory makes it quite obvious that not only does lactase persistance involve a switch, but a switch that gets turned off by being broken.

It is much easier to break a genetic element, or "Functional Coded Element" (FCE) as Behe calls them, than to build one. If lactase persistance was the wild type, then I would explain that two thirds of adults don't have the trait because they have a broken FCE somewhere, and it's likely that there are many, many different mutations that could break it. However, the evidence shows the opposite: adults with lactase persistance have several different mutations. This evidence suggests that lactase persistance involves a broken gene and is the deviation from the wild type. Now, one of the scientists in the video, Dallas Swallow, said quite clearly that she expected there to be one mutation for lactase persistance and was surprised to find out there were several. That's because evolutionary theory makes, or rather made and apologized for it later, a different prediction than intelligent design theory. Evolutionary theory predicts that one mutation for a trait will arise and spread throughout the entire population. According to neo-Darwinian evolution, traits arise after never having existed before because of mutations which then spread through the population by natural selection. So naturally when confronted with a very positive trait like lactase persistance, an evolutionist would assume one particular mutation conferred the advantage and then spread throughout the population. They could even believe that the same mutation occurred at several different times and in several different locations, but it would probably be the same mutation causing the same trait. That's why Dr. Swallow expected a single mutation.

An intelligent design theorist would predict that if lactase persistance was the mutation then it would probably involve several different mutations, since all they would have to do is break or delete a FCE to cause the same trait. This little tidbit shows how evolutionists love to pretend that failed predictions are awesome because it's...a surprise! What fun! We were wrong again! Isn't science wonderful! The point of making scientific predictions is to distinguish between competing theories, but in the field of biology, so we are told, there are no competing theories. Only neo-Darwinian evolution counts, and therefore it doesn't really matter how many failed predictions it makes because, you see, there are no alternatives. See how the game is played? "Our theory's failed predictions don't matter because your theory doesn't make any predictions at all. Wait, you say it does and made the correct ones?  LA-LA-LA-LA-LA-LA-LA. Intelligent design makes no predictions. LA-LA-LA-LA-LA-LA-LA."

Lactase persistance is very much like the persistance of fetal hemoglobin and probably involves a similar type of mutation. Hemoglobin is the protein that, together with its cofactor heme, makes blood red and binds oxygen in the lungs to carry it everywhere in the body. Fetuses have a different kind of hemoglobin than adult human beings for one very obvious reason: fetuses must get their oxygen from their mother's hemoglobin instead of breathing it themselves. In order to do that, fetal hemoglobin has a higher binding coefficient for oxygen than adult hemoglobin, allowing fetal hemoglobin to get enough oxygen off the mother's hemoglobin. When humans are born, a genetic switch turns off the fetal hemoglobin gene and turns on the adult hemoglobin gene. If this switch is broken, then the person would continue making fetal hemoglobin, and some cases have been documented. This is very similar to lactase persistance. There must be a switch in the non-protein-coding region of the lactase gene that gets broken so the repressor FCE doesn't turn off the lactase coding region as the person gets older. That's why the researchers did not find the mutation in the protein-coding region and had to look in non-protein coding areas of the gene. An intelligent design theorist would have found it faster because we would have looked in the non-protein-coding areas first, knowing as we do that gain-of-function traits such as this are highly unlikely to involve gain-of-function changes in protein folds. Oh, and also because evolutionists predicted for decades that most of the human genome, meaning the non-protein coding regions, was junk leftover from the messy process of evolution and had no function.

Another prediction: there is a reason why human beings were designed to only digest lactose as babies and not as adults. There is likely some fitness cost involved in adults being able to digest lactose and drink more milk. The excitable dude in the video said that the selective advantage of lactose persistance is "mind-bendingly strong" because in a culture which uses milk for food getting diarrhea because of it might kill you. I'm looking around today and not seeing a whole lot of places where that is currently the case. In Africa, maybe it will persist or even spread. But I predict the trait will slowly go away in European populations because the selective advantage is no longer there, and there's probably some other, hidden cost working against lactase persistance.

Intelligent design makes predictions. It is a perfectly acceptable scientific theory. The major hold-up is that science during the 20th century came to be dominated by atheists, mostly because Darwin's theory of evolution removed the need for a creator God. The National Academy of Science, for instance, was 92% atheist at last count, a statistic that would elicit howls of discrimination if it was against blacks or some other politically favored group. Not a peep when the discrimination is against Christians. But I believe in science. More than that, I believe in the power of the Truth. What many atheists believe and admire about science is true. It does tend to weed out theories that do not fit the evidence. It just doesn't do it the crisp, clean way that we were taught in school. People do not abandon deeply held beliefs because of rational argument or evidence. In fact, people do not tend to abandon deeply held beliefs at all. But people do tend to accept the more rational argument when they are deciding what to believe initially. Max Planck was an important early 20th century physicist who oversaw one of the greatest scientific revolutions ever, the rise of quantum mechanics over Newtonian or classical mechanics. He had this to say about scientific revolutions: "A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it." Intelligent design has won all the arguments. It's all over but the dying.

Now that's whack.