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Support for evolutionary house of cards model
Brett Smith for redOrbit.com – Your Universe Online
There are three prevailing theories on how evolution works.
One model says that because mutations with big effects are usually fatal to the organism, most mutations have small effects. These small effects would need to build up in order to generate new characteristics and forms, the theory goes.
Another model says mutations don’t change characteristics, insomuch as they set off a chain reaction of changes. Experts liken this theory to an evolutionary house of cards.
A third prevailing model says mutations have no effect at all on the overall health of an organism.
Evolutionary house of cards
In a new study from Yale University, scientists found the ‘house of cards’ model describes evolutionary operations better than the other two theories.
“We found this model applied across vast evolutionary time — in yeast, worms, and flies,” study author Jeffrey Townsend, associate professor of evolutionary biology at Yale, said in a press release.
In the study, researchers used advanced modeling of genomic information from diverse species to gauge the three classical models of how organisms persist over time in light of mutations and natural selection. The investigation expressly examined the effects of these factors on gene expression, which for decades has been identified as a major element of evolutionary change.
The Yale models produced substantial evidence in support of the house of card model. Past research has shown how small pieces of genetic material control the expression of large networks of genes reinforced interest in the “house of cards” theory. The researchers said their work showed how the model applied to various organisms on a genomic scale.
“These models have been around for decades, but new technology for the first time allows us to gather data that can test which model is fundamental to the process of evolution,” Townsend said.
Darwin had proposed that mutations allow a species to survive when threatened by various parts of its ecosystem.
However, a study published back in February revealed bacteria that hadn’t evolved in more than 2 billion years. The study team said this find actually supports Darwin’s theory because the microbes’ live in an environment that doesn’t change – mud resting deep below the ocean surface – meaning there was no push for them to evolve, an argument consistent with the theory of evolution.
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Source: http://www.redorbit.com/news/science/1113391913/support-for-evolutionary-house-of-cards-model-051515/
