Saturday, February 4, 2012

Pleistocene Bison Bone Demonstrates Accelerated Evolution

A revolution in the understanding of the evolutionary process is taking place.  Epigenetic modification takes place on a generational basis in response to changing environmental conditions.  In short, if you need fur, the organism can turn fur on in its offspring.  This is of course, is called intelligent design, although I am sure that this is not what the creationists ever had in mind.

I imagine that some time or the other we will determine that the brain is able to direct those changes.

It is also important to understand that all the necessary genes are sitting there waiting for the to-go sign.  Thus the real question is to determine if new genes are ever created above the level of a single cell.  They can obviously be imported thereafter into a higher organism.

I always though that the best way to deal with the creationist crowd was to merely agree with them, while showing them how it all worked.  This does it quite nicely and perhaps we can now forget all the silly controversy of the past decades.

30,000-year-old bison bone yields new clues on climate-change adaptation


 Thirty-thousand-year-old permafrost bison bones from the Yukon region of Canada.
Photograph by: Handout, University of Adelaide

A 30,000-year-old bison bone plucked from the thawed permafrost inside a Yukon gold mine has helped a team of Australian scientists make a potentially groundbreaking discovery about the way animals adapt to climate change.

A study published in the latest issue of the journal PLoS One describes the Canadian specimen — a bone from the extinct steppe bison, an ancient buffalo that disappeared at the end of the last ice age — as key to unravelling a mystery about how "epigenetic" DNA adjustments can occur more rapidly than full-scale genetic changes in an ecologically stressed species.

The team of six researchers, including scientists from the Australian Centre for Ancient DNA at the University of Adelaide, made their "world-first" findings by probing genetic markers from the remains of six steppe bison specimens unearthed at the Yukon mine.

One of the bison bones produced high-resolution evidence that epigenetic modifications — the switching on or off of genes, without altering a species' fundamental DNA sequence — were occurring in the steppe bison during the Pleistocene era, when woolly mammoths and other megafauna were vanishing from their Arctic and sub-Arctic habitats.

"These 'epigenetic' changes can occur rapidly between generations — without requiring the time for standard evolutionary processes," states a summary of the research.

To reach their conclusions, the Australian team compared the bison bone to other genetic material drawn from a 30-year-old mummified cow from New Zealand and various modern cattle.

"Epigenetics is challenging some of our standard views of evolutionary adaptation, and the way we think about how animals use and inherit their DNA," added project leader Alan Cooper, director of the ancient DNA centre. "In theory, such systems would be invaluable for a wide range of rapid evolutionary adaptation, but it has not been possible to measure how or whether they are used in nature, or over evolutionary time scales."

ACAD researcher Bastien Llamas, lead author of the study, noted that "standard genetic tests do not detect epigenetic changes, because the actual DNA sequence is the same."

But he explained in the summary that the research team was "able to use special methods to show that epigenetic sites in this extinct species were comparable to modern cattle."

Llamas added: "There is growing interest in the potential evolutionary role of epigenetic changes, but to truly demonstrate this will require studies of past populations as they experience major environmental changes."

In 2007, the mummified remains of a steppe bison from about 14,000 years ago were found in the Northwest Territories, yielding new information about the North American range of the soon-to-be-extinct beast.

And in 2009, a team of Canadian scientists published a study in the high-profile journal GSA Today detailing the scientific riches yielded over the years by Klondike-area gold mines, where mining excavations have unearthed a motherlode of ice age fossils, including mammoths, an ancient type of horse and other extinct species.

"A concentration of mining exposures, with relict permafrost that is locally more than 700,000 years old, provides exceptional preservation of paleoenvironmental archives," said the study, led by University of Alberta geologist Duane Froese.

"Since the discovery of placer gold in the Klondike in 1896 and the subsequent gold rush, mining has produced tremendous exposures of surficial sediments within the Klondike goldfields, along with the recognition of abundant Pleistocene fossil bones," the study noted. "Hundreds to thousands of fossils are still produced every year from placer gold mining and provide an invaluable research resource."

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