Controversy swirls around last common ancestor of placental mammals
|January 15, 2014||Posted by News under Evolution, News|
Is the molecular clock right (88-117 mya) or are the bones right (65 mya)?
Genetic studies that compare the DNA of living placentals suggest that our last common ancestor lived between 88 million and 117 million years ago, when the dinosaurs still ruled.
The last common ancestor is said to be a shrew-like creature.
But last year, a team of scientists led by Maureen O’Leary from Stony Brook University challenged this timeline. Through an extraordinarily detailed analysis of the bones of 86 mammals, both living and extinct, O’Leary and her colleagues concluded that placentals arose shortly after the point when the non-bird dinosaurs went extinct—the so-called K/T boundary.
Now, a trio of British researchers have hit back at O’Leary’s study, accusing it of “serious shortcomings.” In a strongly worded paper published today (January 14) in Biology Letters, the authors write that the team has reignited a controversy that “has otherwise been settled.”
Move right along, folks, nothing to see here:
“There’s nothing really wrong with either set of analyses,” Bininda-Emonds continued. “Both are robust. The real problem is that the methods are fundamentally different and make fundamentally different assumptions, so that there’s little point in comparing the apples with the oranges.”
Unless, of course, time periods matter.
Note: Maureen O’Leary. No known relation of UD news writer Denyse O’Leary
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