Why is evolution debate

Next Up:. Available On Air Stations. Full Schedule. All Streams. Twitter Email. Why the Evolution Debate Continues. When Townsend first started studying cancer about a decade ago after training as an evolutionary biologist, he saw that cancer biologists had begun to study mutations at a level of detail that could reveal information about mutation rates at individual sites in the genome.

In a paper published in late October in the Journal of the National Cancer Institute , Townsend and his Yale colleagues presented the results of their evolutionary analysis of mutations in cancers. Cancer cells are rife with mutations, but only a small subset of those are functionally important to the cancer. The selection intensities reveal how important the different mutations are for driving growth in an individual case of cancer — and therefore which ones would be most promising as therapeutic targets.

Although identifying the mutations undergoing the strongest selection is clearly useful and important, selection can also have subtle but important indirect effects on regions of the genome neighboring the target of selection.

One thing they discovered was an apparent correlation between the level of genetic variation and the rate of recombination at any specified region of the genome. Recombination is a process in which the maternal and paternal copies of chromosomes exchange blocks of DNA with each other during meiosis, the production of sperm and egg cells. These recombinations shuffle genetic variation throughout the genome, splitting up alleles that might have previously been together.

By , researchers could get whole-genome data from a variety of organisms, and they started to find this apparent correlation between levels of genetic variation and the rates of recombination everywhere, Kern said.

That correlation meant that forces beyond direct purifying selection and neutral drift were creating differences in levels of variation across the genomic landscape.

Kern argues that the differences in the rates of recombination across the genome reveal a phenomenon called genetic hitchhiking. When beneficial alleles are closely linked to neighboring neutral mutations, natural selection tends to act on all of them as a unit.

Genetic hitchhiking meant that evolutionary geneticists suddenly had a whole new force called linked selection to worry about, Kern said. If only 10 percent of the genome is under direct selection in a population, then linked selection means that a much larger percentage — maybe 30 or 40 percent — might show its effects.

Zhang points out that linked neutral mutations are still neutral. Kern agrees: The neutral mutations are still neutral — but they are not behaving as neutral theory would predict. Recent human evolution is largely a history of migrations to new geographical locations where humans encountered new climates and pathogens to which they had to adapt.

In , Kern published a paper showing that most human adaptations arose from existing genetic variation within the genome, not novel mutations that spread rapidly through the population. Update for p. ET Feb. Now both Coyne and Arel have posted post-debate commentaries.

Their bottom line? No harm was done to science, but it still wasn't a good idea. Two publications from the Pew Research Center last week highlight just how pervasive this assumption is when it comes to questions about evolution and religion. One report demonstrates how the phrasing and sequence of questions about attitudes regarding evolution significantly influence survey results.

When people were first asked to choose between only two options—that humans evolved or that they have always existed in their present form—and only to differentiate between a God-guided interpretation of evolution or an atheistical one as a follow-up question—a higher percentage of respondents chose creationism than in a survey in which three options atheistical evolution, theistic evolution, and creationism were all presented together.

One might see this as evidence that some conflict-averse people are inclined toward a middle ground when presented with one. But this begs the question of why anyone would see God-driven evolution as a middle position.

Today, however, theistic evolution is often presented as an insincere detente between polar opposites, to be derided as incoherent by biblical creationists and New Atheists alike. Last week Pew also published a brief history of the evolution debate in the United States that makes this conceit even clearer. There is a prevailing sense that the evolution debate is fundamentally unlike other forms of science denial: driven not by greed or political power, but instead by religion.

When writing history, just as in designing a public opinion survey, a lot of presupposition goes into how questions are framed. The evolution concept was controversial even before Darwin put his theory into writing. In the wake of the French revolution , the idea that people could change—whether it was due to influence of the environment or through the benefits accrued in their lifetime being passed down to next generations—was seen as a radical antidote to conservative ideas of hereditary nobility and social caste.