Kiwi birds younger than originally thought, research shows
New Zealand's kiwi may be one of the world's oddest birds – flightless, nocturnal, an enigmatic dirt digger with nostrils at the end of its long bill. But the national symbol also has a lot to tell the world about evolution during the most recent ice age.
|An endangered rowi kiwi or okarito kiwi, Apteryx rowi, at the West Coast Wildlife Centre in Franz Josef, |
South Island, New Zealand [Credit: Joel Sartore, National Geographic Photo Ark]
Earlier research, based on simple methods of DNA testing using a single genetic marker, appeared to show that kiwi had developed into various species before the Pleistocene ice age that began some 2.6 million years ago and ended about 11,000 years ago. Many other creatures around the world had been classed the same way using similar methods.
But by deploying new and far more sophisticated DNA testing which tracks thousands of genetic markers on the kiwi genome, Weir's research shows kiwi underwent an "explosive" period of genetic diversification – evolving into new species or subspecies – during the middle and late Pleistocene period.
|An endangered North Island brown kiwi, Apteryx mantelli, at the Kiwi Birdlife Park in Queenstown, |
New Zealand [Credit: Joel Sartore, National Geographic Photo Ark]
Weir (above, photo by Ken Jones) found that the rate of diversification increased five-fold during the glaciation period, to a level even greater than Charles Darwin's famous finches from the Galapagos Islands.
Weir is among the first to use the new DNA techniques to measure evolutionary changes. "These new methods are going to be used extensively in the next 10 years," he says. He expects scientists to revisit evolutionary studies of many birds and animals in North and South America and other parts of the world that had periods of glaciation. "The old system is out the window now."
Weir and researcher Oliver Haddrath of the Royal Ontario Museum (ROM) carried out the massive task of analyzing the genetic data was carried out on Canada's SciNet supercomputer. Some 300 samples of kiwi blood were collected by two New Zealand collaborators and by Allan Baker, a New Zealander by birth who was senior curator of ornithology and head of the Department of Natural History at the ROM before he died in 2014. The team also used previously published data from fossilized kiwi material.
Source: University of Toronto [August 30, 2016]