A pair of researchers have uncovered a surprising lack of mutation in the so-called “DNA barcodes” of 100,000 animal species that contradicts the mainstream scientific understanding of the age of life on earth.

Faith Wire’s Carly Holiman reports that Mark Stoeckle of Rockefeller University in New York, and David Thaler at the University of Basel in Switzerland, “examined five million gene snapshots called ‘DNA barcodes.’ The barcodes, collected from 100,000 animal species, including humans, revealed what came as a shock to the researchers: nine out of 10 species on Earth today — humans included — came into being around 100,000 to 200,000 years ago.”

“Stoeckle, lead author of the study, explained in the journal Human Evolution that while the popular biological belief is that species with large, long-standing populations (e.g. ants, rats, humans) would become more genetically diverse over time, the reality is that genetic diversity has been ‘about the same’ for hundreds of millennia.”

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The 100,000 barcodes examined show a conspicuous lack of “neutral” mutations, i.e. small genetic changes over generations that do not negatively or positively impact a species’ chance of survival. “Like the rings of a tree,” Holiman explains, these neutral mutations can indicate a species’ age.

“This conclusion is very surprising, and I fought against it as hard as I could,” Thaler told AFP.

But, Holiman says, it was impossible for the scientists to ignore their findings.

“The only question that remains — and it’s a rather big question,” she says, “is how 90 percent of the animal life on Earth is roughly the same age, genetically speaking. In other words, why and how did the vast majority of species emerge at around the same time?”

Jesse Ausubel, the director of the Program for the Human Environment at The Rockefeller University, guesses that a large environmental event may be to blame.

“Viruses, ice ages, successful new competitors, loss of prey—all these may cause periods when the population of an animal drops sharply,” Ausubel told AFP. “In these periods, it is easier for a genetic innovation to sweep the population and contribute to the emergence of a new species.”

The study also inadvertently discovered that species have very clear boundaries in their genes, and that there is a distinct lack of evidence for “in-between” species, which Holiman says perplexed Darwin himself. Evolutionary theory takes for granted that one species evolved into another, but as of yet there exists no reliable evidence for speciation, which would be what is needed to fully support the theory of macroevolution.