Warmer climate boosts evolution: Okay, so iguanas aren't mammals, and I doubt Charles Darwin ever visited Sloppy Joe's in Key West, Florida, but the graphic still illustrates the point.
Courtesy Apollo13Ma (background photo), public domain and Mark RyanA study out of New Zealand says a warmer climate speeds up molecular evolution in mammals. The concept isn’t exactly a new one. Scientists have known that a warmer environment increases the pace of microevolution for other types of life, such as some plants and marine animals, but evidence that it affects mammals – which are warm-blooded (meaning their temperature is regulated internally) – has not been observed before.

Lead researcher, Len Gillman from Auckland University of Technology, said the result of the study was “unexpected”.

""We have previously found a similar result for plant species and other groups have seen it in marine animals. But since these are 'ectotherms' - their body temperature is controlled directly by the environment - everyone assumed that the effect was caused by climate altering their metabolic rate.""

Since DNA can potentially mutate each time a cell divides into two copies of itself, the faster (and more often) these divisions take place, the more chances advantageous mutations will be passed onto subsequent generations, and the faster microevolution takes place.

Gillman and his crew traced and compared small genetic changes in 130 pairs of related species that lived in different latitudes, focusing on a single gene in each pair. They then compared the gene against that of a common ancestor, and were able to determine which of the two mammals’ DNA had mutated (microevolved) more rapidly. The changes were small-scale, but the species living in the more tropical environment showed a faster pace in its level of molecular evolution.

The results of the study appear in Proceedings of the Royal Society B.

LINKS
Discover magazine story
BBC story
More about evolution

Tags : evolution, mammals, global warming, environment, micro-evolution

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Influenza virus: Negative-stained transmission electron micrograph (TEM) depicting the ultrastructural details of a number of influenza virus particles, or “virions”.
Courtesy pingnews.comEvery time flu season comes around there seems to be concern whether the current flu shot vaccine will be able to stave off the viral attack. That’s because viruses and bacteria have a habit of mutating, which subsequently makes a particular vaccine against them ineffective. So each year the medical profession comes up with a vaccine they think will be an effective counterattack against the invading virus. Our own natural antibodies do something similar.

"We've known for a long time that our antibody-forming system adapts itself to every microbe we encounter," said Gerald Weissmann, M.D. He’s Editor-in-Chief of the FASEB Journal where a new study on the subject appears. “What we didn't understand fully is exactly how this happens,” he added.

When viruses or other microbes attack us, our body’s defense system goes into action - via evolution - figuring out ways to create antibodies that will successfully neutralize the invader. There’s two ways our bodies do this: either by mutation of a single cell or mutation of a cluster of cells.

New research out of Detroit’s Wayne State University shows how clusters of our cells quickly customize themselves to fight new forms of attacks. It has to do with how our genes code for antibodies. When a RNA polymerase replicates DNA it moves across it like a scanner. If the scan is smooth, a single mutation (or none at all) takes place. But if the RNA is stalled over the DNA then in some cases multiple mutations occur. The process allows for rapid deployment of tailor-made antibodies to attack the invader.

Why is this important? Well, according Weissmann, as our climate warms the ranges of parasites and microbes expand, making more people vulnerable to infectious diseases than they have been in the past.

“Now that we know [how cluster mutations occur], we can begin to find ways to manipulate this process so illnesses can be prevented or made significantly less dangerous."

LINKS
Science Daily report
DNA from the Beginning (good primer)
Explanation of the polymerase chain reaction

Tags : micro-evolution, evolution, antibodies, RNA, DNA, influenza

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Charles Darwin, c. 1881: Source: Wikipedia (Public Domain)A group of Galapagos Island birds known as Darwin’s Finches continue to do what they’re best known for: evolving. A recent study published in the the journal Science, details how new competition for food has resulted in some rather quick adaptations in the beaks of some of the famous finches that were instrumental in Charles Darwin formulating his theory of evolution.

Finch: US Fish and Wildlife photo courtesy Wikimedia CommonsPeter Grant of Princeton University has been studying the finches for decades. Early on he noticed that a medium sized ground finch, Geospiza fortis, living on the Galapagos island of Daphne, faced no competition for food and ate both small and large seeds. Then, in 1982, competition arrived in the form of a larger ground finch, Geospiza magnirostris, setting in motion a classic case of microevolution.

The new species was able to break open the larger seeds of the Tribulus plants three times faster than G. fortis and soon depleted the island’s large seed supply.

Over the next twenty years the population of G. fortis finches with larger beaks declined dramatically due to the competition, leaving only a population of smaller beaked G. fortis which didn’t compete for the larger seeds favored by G. magnirostris.

What makes this unusual is that it’s given scientists a rare opportunity to actually observe first hand a change in an animal’s appearance caused by the arrival of a new food competitor.

SOURCES AND LINKS

Minneapolis Star Tribune story
Darwin’s Finches
More on Darwins’s Finches
Charles Darwin
The Galapagos Islands
Charles Darwin Foundation

Tags : evolution, Darwin, micro-evolution, Galapagos Islands

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