A team of researchers has added to our knowledge of the genetic mutation rate in humans, as they report in Current Biology.
In the study, scientists compared thousands of genes in two men who were distantly related, having shared an ancestor who was born in 1805. Within the nucleotides analyzed on the Y chromosome, the two men had only four genuine genetic differences between them. (Eight other differences arose in the cell lines derived from cells taken from the men and cultured for analysis.)
By extrapolating that number based on the scope of the research, the team concluded an average of one mutation out of every 30 million nucleotides per generation, said study coordinator Chris Tyler-Smith of the Wellcome Trust Sanger Institute. “New mutations are responsible for an array of genetic diseases. The ability to reliably measure rates of DNA mutation means we can begin to ask how mutation rates vary between different regions of the genome and perhaps also between different individuals,” he explained.
Joseph Nadeau of Case Western Reserve University, who was not involved in the study, noted, “New mutations are the source of inherited variation, some of which can lead to disease and dysfunction, and some of which determines the nature and pace of evolutionary change.”
This research is interesting and may prove useful, indeed, for disease researchers, given that most mutations that have any effect at all have a deleterious effect. And as far as scientists have seen, mutations that have a positive effect nonetheless result in the effect by corrupting or deleting information, not adding it—as Darwinian evolution would require. Also, in matching mutation rates with evolutionary dates, creationists should bear in mind that the mutation rate may not have been constant over the years (although evolutionists generally make this assumption).
In related news, a study of Central Asian “ethnic groups” shows that such groupings are more social constructions than biological truths. Researchers led by Evelyne Heyer of the Musée de l’Homme learned that genetic differences between members of two so-called ethnic groups were actually greater than the differences between the two groups.
Heyer explained, “Our results indicate that, for at least two of the Turkic groups in Central Asia, ethnicity is a constructed social system maintaining genetic boundaries with other groups, rather than being the outcome of common genetic ancestry.”
The team’s research is reflective of what we have long argued about all human people groups, including what are mistakenly called “races”; even though some groups share superficial and cultural differences, we are all equally human in the eyes of biology—and all of “one blood,” as the Bible teaches (Acts 17:26). Differences in such features as skin tone can be explained by such factors as natural and artificial selection working on pre-existing genetic variation, similar to what is described in a LiveScience article this week (though we would note that all humans probably diverged from an original mid-brown shade of skin, some becoming lighter and others darker).
The many differences in dog fur are reducible to just a few genetic factors, a team reports in Science. So what does that teach creationists about the tricks of biology?
Dog hair seems to be about as diverse as something can get: it comes in many colors, lengths, thicknesses, and degrees of curliness. Researchers at the (U.S.) National Human Genome Research Institute wondered what the genetic basis was for some of those these differences.
The scientists began by keeping things simple: they looked for genetic variation in the genome of just one breed of dog, the dachshund, which comes in short-haired, long-haired, and wiry-haired varieties. After looking at some 50,000 “spots” (pardon the pun) in the genetic codes of 100 dachshunds, the researchers discovered that differences in one location on canine chromosome 13 determine the wiriness of dachshund hair; a particular gene known as R-spondin-2 encodes a protein that results in the wiry hair follicles and produces the characteristic “mustaches” of some dog breeds. Meanwhile, a mutation in a gene called FGF5 correlated with longer hair; 91 percent of the long-haired dogs in the study had the mutation, compared to only 4 percent of the short-haired dogs.
In a corresponding study, the researchers examined the genes of 76 Portuguese water dogs to pin down the genetic cause of curly hair. They learned that a difference in the gene for hair protein keratin caused the curliness.
Knowing that differences in those three genes alone resulted in differences in hair length, wiriness, and curliness, the researchers embarked on a bigger project: they analyzed the genomes of dogs from 80 breeds (nearly 1,000 dogs in total) to learn how the identified genetic changes interacted to result in the varieties of dog hair. They discovered that different combinations of the gene types result in the seven coat types most common among the dogs sampled.
For example, basset hounds have none of the three mutations, and instead have short, straight-haired coats. Dogs with all three mutations have long, curly hair and mustaches, such as the bichon frisé. (For this very reason, AiG’s Ken Ham has fondly referred to his family’s bichon frisé as a “mutant”—see As I Always Said: “It’s a Mutant!”)
Thus, the incredible diversity of dog fur is largely due to differences in just three genes. Cornell University geneticist Gregory Acland commented, “All the unique characteristics are something that occurred once a long time ago and have been preserved ever since.” That’s due not only to the effects of natural selection (e.g., only long-haired dogs surviving in cold climates), but also due to the power of artificial selection (e.g., breeders selecting for certain traits, resulting in dogs with specific characteristics based on everything from farmers’ needs to pet owners’ fancies).
What does this study tell creationists? It gives us a good idea of the scope of genetic differences required to account for the diversity within one part of what was probably one created canid kind (extending beyond dogs to wolves, dingoes, etc.). We cannot say for sure how many of these differences are the result of a mutation and how many were simply due to the diverse information God gave each created kind; however, we can get a better idea of how the kind may have changed over the four millennia since Noah’s Ark.
Peppered moths, move over! There’s a new alleged “icon of ‘evolution in action’” in town.
Reporting in Science, Harvard biologist Catherine Linnen and colleagues describe the “rapid adaptation under ecological pressure” of pale deer mice living in the sand dunes of Nebraska.
Usually deer mice, which are common in North America, have a dark coat. That helps them blend in with the dark soil and escape the notice of overhead predators, such as owls and hawks. The mice just outside of Nebraska’s Sand Hills sport dark fur, too. But living among the Sand Hills are mice with a pale coat, a “striking contrast,” said Linnen, to the dark-furred mice elsewhere. Of course, this helps the mice blend in with their lighter-colored Sand Hills background.
The scientists conducted an investigation to determine the gene (called the Agouti gene) that codes for the light-colored coat. In their paper’s abstract, they report:
We studied cryptically colored deer mice living on the Nebraska Sand Hills and show that their light coloration stems from a novel banding pattern on individual hairs produced by an increase in Agouti expression caused by a cis-acting mutation (or mutations), which either is or is closely linked to a single amino acid deletion in Agouti that appears to be under selection.
Thus, as BBC News reports, the pale coat color comes from “variation [in] a gene that already exists, rather than [in] a new type of gene altogether.” It could even be that the entire variation is due to the deletion of a single amino acid described by the authors. Creationists can interpret this finding in one of two ways:
Additionally there is the issue of the timing of this genetic mutation (if, indeed, it was a mutation). According to Linnen, “We were also intrigued by the fact that Sand Hills had formed within the last 8,000 to 15,000 years, which implies the light color of the Sand Hills mice became advantageous only recently.” Based on estimates of mutation rates, the scientists concluded the genetic variation for pale fur originated around 4,000 years ago.
To evolutionists, the appearance and spread of a mutation in four millennia is “rapid.” And although there are other examples of rapid change within a single species in only decades (see, e.g., item #1 of the June 6 News to Note), the deer mouse variation has been traced to an actual genetic difference—whereas others (as in the example provided) may more likely be due to non-genetic factors. (Of course, even the evolutionary estimate of 4,000 years—if accurate—fits into the creationist framework.)
This study also reaffirms the potency of natural selection (an important biological concept). The authors say the lighter-colored fur gives the pale mice a 0.5 percent survival advantage in the Sand Hills—which may not sound like much, but as study coauthor Hopi Hoekstra (also a Harvard University biologist) explained, “It doesn’t seem that much, but multiplied over thousands of individuals over hundreds of years, it makes a huge difference.”
So while the deer mouse is poised to become a new icon of evolution, the entirety of this study is easily understandable from the creation paradigm: natural selection is acting on a genetic difference (likely a mutation) that has not increased the quantity of genetic information in the deer mouse. That process of adaptation, even if it continued for eons, could never result in one organism turning into another (i.e., by the generation of novel genetic information and anatomical features), as Darwinian evolution (a.k.a. molecules-to-man evolution) requires.
(For an in-depth analysis of a similar study a few years back, we recommend an article by our staff geneticist Dr. Georgia Purdom: Evolution or Adaptation?)
A zoo near Bristol, England, has been attacked for its promotion of “creationist ideas,” even though a zoo spokesperson called life “the product of both God and evolution.”
Noah’s Ark Zoo Farm in Wraxall receives more than 100,000 visitors each year, including schoolchildren. That’s a problem, says the British Humanist Association, which accuses the zoo of undermining science education.
“We’re very concerned because it will undermine education and the teaching of science,” explained British Humanist Association education officer Paul Pettinger, who visited the zoo earlier this year. Pettinger cited as problematic such signs as one that describes how “three great people groups” could be the descendants of Noah’s sons.
The association is asking tourism boards to stop promoting the zoo, and has reportedly contacted tourism boards including the British and Irish Association of Zoos and Aquariums (BIAZA) and Visit Britain. According to BBC News, Visit Britain has clarified that it only checks the zoo under its “Visitor Quality Assurance Scheme” and has no official statement on the zoo’s content. BIAZA responded similarly.
The official statements from the zoo itself are intriguing. Its website features a section on “creation research” that explains,
Popular media presents us with only two theories to explain the origins of life: Darwinism or 6000BC Creationism. We think both are flawed in their theory; both are extreme in their own rights. One theory takes the evolution that is clear to us all and extrapolates it backwards to imply there is no need for a God or a Creation; the other requires a God for Creation but requires the Genesis chronologies are complete and that there is a slow Noah's Flood lasting 150 days to reach its height, in order that most of the geological column can be laid down in this time.
Another page on the site seems to suggest that while the zoo owner does not accept the Bible’s straightforward teachings on creation, they nonetheless do not unquestioningly accept old ages and assumption-riddled radiometric dating, either.
All this may provide a background for why the zoo owner Anthony Bush, billed by the BBC as a “former evangelical preacher,” reportedly said, “I think God created life. I have no idea when.” He added, “Although technically creationists, we do not hold the stereotypical creationist views that the world was created in 6,000 years and there is no evolution.” He also pointed out that the zoo presents a variety of views. And as for their claim that life is a product of both God and evolution, their understanding of “evolution” seems identical to our own—variations in the genetic information of the original created kinds, not molecules to man in the Darwinian sense.
Zoo research assistant Jon Woodward also fought off an attack from the BHA that the zoo “misleads the public by not being open about its creationist agenda.” Woodward responded, “To say that we are not upfront with our beliefs is unfounded. The name ‘Noah’s Ark’ is the first indicator.” He continued:
We also have much material on our website, which is not disguised or hidden, as well as being on our leaflet. Our education policy is purely based around the National Curriculum. At no point is religion taught in the classroom, unless requested, as that would go against the National Curriculum.
We are offering our visitors the chance to look at the evolution/creation debate. As it is a free country, that is within our right. Contrary to a small minority of people’s claims, we do not teach false science. This is clearly shown within the zoo with one exhibition talking about Darwin and another offering another point of view.
First and foremost, we would defend the zoo as privately owned and thereby entitled to present its views to its patrons and otherwise conduct business so long as it does not violate the law. Our Creation Museum does the same, and likewise is privately owned and on private property; yet we have likewise come under attack from atheists wishing to censor our museum and the views expressed in it.
What is also notable is that the zoo is less insistent on a recent creation than we are, and it claims to seek out an “open, yet critical, scientific approach to explaining the origin and diversity of life.” Yet any endorsement of (supernatural) biological design must be out-and-out excised, say the humanists, who increasingly want to censor creationist ideas wherever they may be—and even if they’re based on good, observational science.
We can all agree that evidence of intelligent design has been “shot down.” But is it good science or biased presuppositions that is doing the “shooting”?
One premise of intelligent design advocates are examples of “irreducible complexity,” where all the components of a biological system must have been in place, functioning correctly, from the beginning for the system to have worked at all—such as is the case with a (human-designed) mousetrap. According to intelligent design advocates, this indicates that step-by-step evolution (à la Darwin) cannot explain all biological systems.
Although young-earth creationists’ defenses of design in nature do not rest on the idea of irreducible complexity, we do find it to be a fair argument (in principle). That said, determining which biological systems are supposedly “irreducible” is not always easy.
Brandon Keim, writing in Wired magazine, reports on research newly published in Proceedings of the National Academy of Sciences that purports to show the reducible complexity of “a mitochondrial molecular machine.” Keim writes,
[N]ew research comparing mitochondria, which provide energy to animal cells, with their bacterial relatives, shows that the necessary pieces for one particular cellular machine—exactly the sort of structure that’s supposed to prove intelligent design—were lying around long ago. It was simply a matter of time before they came together into a more complex entity.
Without even reading on, let’s stop for a moment and consider some of the questions and objections we might have with the team’s research:
Evolutionists believe that mitochondria (a cell organelle) are descended from bacteria that were, at some point, engulfed by independent cells in the beginnings of an endosymbiotic relationship. That’s why finding the same “pieces” in bacteria as in mitochondria are necessary for an evolutionist.
A “protein machine” called TIM23 is part of the workings of mitochondria. TIM23 delivers other proteins to the mitochondria that originate elsewhere in the cell. Bacteria don’t have TIM23, so evolutionists must conclude it evolved in mitochondria. But, as Keim writes, “This seems to pose a cellular chicken-and-egg question: How could protein transport evolve when it was necessary to survive in the first place?”
So what is the big breakthrough the scientists have found to answer the question—and how does it answer our questions posed above? Keim explains, “When they analyzed the genomes of proteobacteria, the family that spawned the ancestors of mitochondria, [the] team found two of the protein parts used in mitochondria to make TIM23.”
The authors note that “[a]lthough the bacterial proteins function in simple assemblies, relatively little mutation would be required to convert them to function as a protein transport machine.” According to Keim, “Only one other part, a molecule called LivH, would make a rudimentary protein-transporting machine—and LivH is commonly found in proteobacteria.”
Michael Gray, a cell biologist at Dalhousie University who was not involved in the study, commented, “These three proteins don’t perform precisely the same function in proteobacteria, but with a simple mutation could be transformed into a simple protein transport machine that could start the whole thing off.”
Which brings us back to our questions. First of all, even if the two TIM23 protein parts found in the proteobacteria were found together with LivH, would that function sufficiently for the survival of mitochondria? Keim says the result would be “rudimentary,” but we wonder how much the scientists even know about the exact workings of TIM23.
Second—and more importantly—how would the TIM23 pieces self-assemble? If the team’s hypothesis is correct, bacteria given the necessary pieces should be capable, given ample time, of assembling and operating a basic TIM23 protein delivery system. Yet Gray and the authors note the mutations that would be required. How simple are these mutations, and how frequently are they observed in bacteria?
Our guess is that, posed with such questions, the researchers would say that over millions of years some proteobacteria (somewhere along the line) had the right protein pieces, LivH, and the right mutations, and that all of it came together in just the right way, simultaneously—the apparatus aligning perfectly to become functional, even if just in a rudimentary sense. Voilà; the “irreducibly complex” structure becomes reducibly complex and thus explainable evolutionarily. (The scientists presumably have faith that other examples of irreducible complexity will turn out the same way.) Given that, we have two objections:
Having decided against creation, evolutionists, it seems, choose evolution by default as the only remaining possibility and are consequently forced to defend its plausibility no matter what—even if it means generating rescuing devices to explain the origin of complex biological features in a manner scientists have never observed in nature.
http://www.answersingenesis.org/articles/2009/09/05/news-to-note-09052009