Showing posts with label RNA. Show all posts
Showing posts with label RNA. Show all posts

Monday, January 25, 2010

Initial Evolution of Life Non-Darwinian??

Spock: "Well, its life, Jim, but not as we know it." New Scientist has an article on the evolution of early life in which it is posited by several researchers that this progressed in strikingly non-Darwinian fashion. Mark Buchanan writes:
JUST suppose that Darwin's ideas were only a part of the story of evolution. Suppose that a process he never wrote about, and never even imagined, has been controlling the evolution of life throughout most of the Earth's history. It may sound preposterous, but this is exactly what microbiologist Carl Woese and physicist Nigel Goldenfeld, both at the University of Illinois at Urbana-Champaign, believe. Darwin's explanation of evolution, they argue, even in its sophisticated modern form, applies only to a recent phase of life on Earth.
What is not so clear from the initial section of the article is that this applies to the microbiological world almost exclusively. The authors argue that, at an early stage of evolution, horizontal gene transfer was largely responsible for the genetic code being spread among all organisms:
"In some sense," says Woese, "the genetic code is a fossil or perhaps an echo of the origin of life, just as the cosmic microwave background is a sort of echo of the big bang. And its form points to a process very different from today's Darwinian evolution." For the researchers the conclusion is inescapable: the genetic code must have arisen in an earlier evolutionary phase dominated by horizontal gene transfer.
Given the behavior of viruses (H1N1 for example) in which genes are swapped between different viral strains and that of ERVs in which viral RNA is written into the DNA of living organisms, perhaps this is not as surprising as it sounds. The authors are quick to note that the vast majority of evolution is now Darwinian in nature but that we see evidence of how things may have started out. Read the whole thing.

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Thursday, December 03, 2009

The Most Important Scientific Breaththrough of the Last Decade

The Irish Times has a story on the most important scientific discoveries of the last ten years. Among the big winners: the Toumai skull, Sahelanthropus tchadensis, MicroRNAs, the discovery of the speech gene FoxP2, and the human genome. The ambiguity of the Toumai skull is correctly described. It was squashed flat and it is not clear even quite what it is. About FoxP2, they write:
Two mutations in a single gene may have provided the evolutionary push that opened the way to human conversation. It all comes down to a master switch for language, the Foxp2 gene, which was first identified in 2001. It was found because of its associations, when switched off, in speech and language problems in humans. The following year German and British researchers compared our Foxp2 gene with matching ones in chimps, gorillas, orang-utans and rhesus macaque monkeys. They found two alterations seen only in humans, and surmised that these mutations had opened the way to language. Extensive research since has shown how the altered Foxp2 also triggered physiological changes that delivered the capacity to talk, something that gave humans a huge evolutionary advantage. Researchers are now studying how Foxp2 interacts with a large collection of genes associated with language.
As you read the discoveries, remember that most of them would have never come about without a modern, scientifically valid understanding of the universe—something that young earth creationism cannot provide.

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