|Evolution in the News - November 2012|
|by Do-While Jones|
Mutation rates aren’t what they used to be. (They never were.)
At the end of this month’s feature article, we told you about how mutations in junk DNA were thought (by evolutionists) to tell how long ago closely related species split from a common ancestor, and why the method is fundamentally flawed. Because the method is based on a faulty premise, we weren’t surprised to read this in last month’s journal, Science.
New work suggests that mutations arise more slowly in humans than previously thought, raising questions about the timetable of evolutionary events. 1
This isn’t really news. Scientists have known there has been a problem for nearly 10 years.
The first sign that something was amiss came in 2003, when a study tracking genes that cause hemophilia, muscular dystrophy, and other diseases in parents and children found slower mutation rates than expected. 2
Of course, YOU knew something was amiss more than four years before the evolutionary scientists did, because we told you in our newsletter! 3
But, even though scientists have known there are problems with molecular dating for a decade, they used it anyway.
By their own admission, evolutionists used circular reasoning to calibrate the molecular clock.
For the past 15 years, researchers have estimated the speed of the molecular clock by counting the mutational differences between humans and primates in matching segments of DNA, then using different species' first appearances in the fossil record to estimate how long it took those mutations to accumulate. For example, the fossils of the oldest known orangutan ancestor are about 13 million years old, so DNA differences between humans and orangutans had about that long to accumulate. 4
When researchers plugged this rate into their equations, most got dates between 4 million and 6 million years ago for the split between the ancestors of humans and chimps. That dovetails pretty well with fossils identified as the earliest known hominins … 5
In other words, they used the presumed ages of fossils to determine the clock rate, and then used that clock rate to determine the age of the fossils. Naturally, they got consistent answers (“most” of the time). If they had initially assumed the split happened twice as long ago, then they would have gotten a mutation rate that is twice as slow, and then using that slower rate they would have concluded that the fossil split happened twice as long ago.
Circular reasoning uses an assumption to come to a conclusion, and then uses that conclusion to verify the assumption. That’s why circular logic always gives consistent results, whether the assumption is true or not. Circular reasoning is not a valid method of reasoning.
Scientists should have known that using the date of fossils to calibrate the clock rate, and then using the calibrated clock to determine the date of the fossils is not valid. But the evolutionists who wrote last month’s peer-reviewed article know there are other problems with the method, too.
But this method of calculating the mutation rate has drawbacks. For starters, it assumes that the fossil dates accurately record the first appearance of a species, but that can change with a new find. Second, there are no fossils of our closest living relatives: chimps and gorillas. Third, the method assumes that species split at the same time as their genes diverged, but in fact, genetic separation can be millions of years earlier than species divergence. Finally, the method assumes that mutation rates are similar across apes, although factors such as generation time—the average number of years between generations—affect the rate. 6
Using the presumed time since humans split from apes to determine the mutation rate has never been valid. Now, evolutionists have independently determined mutation rates as a byproduct of studies of genetic diseases.
The Icelandic study found that on average, every newborn baby has 36 spontaneous new mutations, those not inherited from either parent. 7
Now they have a legitimate mutation rate that is much lower than previously thought. That leads them to these conclusions:
For the past 45 years, researchers have used the number of mutations in DNA like a molecular clock to date key chapters in the human evolutionary story, such as the dawn of humankind millions of years ago and the exodus of modern humans from Africa in the past 100,000 years.
Now it seems that the molecular clock ticks more slowly than anyone had thought, and many dates may need to be adjusted. Over the past 3 years, researchers have used new methods to sequence whole human genomes, allowing them to measure directly, for the first time, the average rate at which new mutations arise in a newborn baby. Most of these studies conclude that the mutation rate in humans today is roughly half the rate that has been used in many evolutionary studies since 2000. “Together, these papers make a convincing case that the human sequence mutation rate is substantially less than the one previously used,” says Harvard University population geneticist David Reich, co-author of one recent study. “As a result, genetic estimates of dates for ancient events are going to be older than previously reported.”
The question now is how much older? Three new studies have taken a stab at providing an answer, trying to apply the slower mutation rates to major events in human evolution. In the past month, they have published a range of dates that sometimes fit with evidence from the fossil record—and that are sometimes way off, particularly for events further back in time. 8
“The mutation rates are so up in air,” said paleogeneticist Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, in August, when his team published big margins of error—from 170,000 to 700,000 years ago—for the date when our ancestors split from Neandertals and their close cousins, the Denisovans. As a result, the timing of some events in human origins is now “very murky,” says paleoanthropologist Chris Stringer of the Natural History Museum in London. 9What's more, the new rate slows the pace of evolution in apes to a downright crawl …. It puts the split of humans and chimpanzees, for example, at between 8.3 million years ago and 10.1 million years ago—far too early, given current fossil dates. The split of the lineages leading to orangutans and the African apes, including humans, goes back to 34 million to 46 million years ago, Reich says. “A human-orangutan split at 40 million years is absolutely crazy,” says paleoanthropologist David Begun of the University of Toronto, St. George, in Canada, who notes that fossils of likely orangutan ancestors date from 9 million to 13.9 million years ago. 10
Much of the article we have been quoting has been devoted to coming up with ways to explain away the discrepancy between fossil dates and molecular dates. The primary excuse is the unsubstantiated assertion that mutation rates must be highly variable and must have been much faster in the past. Sooner or later, someone will come up with a story that most evolutionists can live with, and that will become the new “truth.”
The real reason why the fossil dates don’t agree with the molecular dates is because both are based on the false premise that apes and humans had a common ancestor. The fact is that they didn’t have a common ancestor, so the differences in DNA are not the result of random mutations over a long period of time.
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Gibbons, Science, 12 October 2012, “Turning Back the Clock: Slowing the Pace of Prehistory”, pp. 189-191, http://www.sciencemag.org/content/338/6104/189.full?sid=cb155686-4d36-4626-9c37-1eccec86ec78
3 Disclosure, July 1999, “The DNA Dilemma”, http://scienceagainstevolution.info/v3i10f.htm
4 Gibbons, Science, 12 October 2012, “Turning Back the Clock: Slowing the Pace of Prehistory”, pp. 189-191, http://www.sciencemag.org/content/338/6104/189.full?sid=cb155686-4d36-4626-9c37-1eccec86ec78