© D. DenverThe rate at which changes happen in the DNA of Adélie penguins (one shown here with chicks) has been faster than scientists had thought, a new study suggests.
The evolutionary march of the penguins happened in double time, according to new genetic calculations.
A study of DNA from ancient and modern Adélie penguins suggests that scientists may have miscalculated the rates at which genetic clocks tick off evolutionary time in other species as well. A team of researchers collected mitochondrial DNA from penguins currently living in rookeries in Antarctica and from bones of penguins that had lived in the same spot as long as 44,000 years ago. Analysis of the DNA reveals that the penguins are evolving on a molecular scale two to six times faster than standard calculations indicated, the team reports in the November Trends in Genetics.
Mitochondria are small structures that generate power inside cells. The organelles were once free-living bacteria and have kept their own circle of DNA, which encodes many of the proteins needed for power production. The function of mitochondria is so crucial to the cell that any changes to mitochondrial genes are likely to throw a wrench into a cell's energy-generating capabilities. As a result, the mitochondrial DNA has evolved slowly. Scientists can use the number of changes in mitochondrial DNA between different species to calculate a molecular rate of evolution and estimate how long ago the species shared a common ancestor.
