Wednesday, January 9, 2013

Study charts DNA mutations



CURIOUS SUBJECT: An Adelie penguin in the Ross Sea area in Antarctica.
A scientist who used to study crime scenes for a living is now using ancient penguin DNA from Antarctica to uncover the past and make predictions for the future.

The three-year project is an extension of a previous study published by former forensic scientist and senior lecturer at the University of Auckland Dr Craig Millar and his collaborators about a decade ago.

The previous study used DNA from different time periods to measure the rate of evolutionary change in Adelie penguins, and discovered that it was five to seven times faster than previously thought.
Dr Millar said it measured a small but important genome section that was used extensively in forensics, but genome-sequencing technology had improved significantly since then.

The process was now much faster and radically cheaper, allowing his research team to sequence entire genomes found in well-preserved Adelie penguin bones as well as living birds. "The technology has just revolutionised the sequencing process. The cost of it is plummeting," Dr Millar said.

The new technology would enable the research team to examine what evolutionary changes had occurred in Adelie penguins since the peak of the last glacial period, between 18,000 and 25,000 years ago.

Antarctica had warmed about 10 to 12 degrees Celsius since deglaciation started about 12,000 years ago, and the team wanted to discover what, if any, evolutionary response that had prompted. "It allows us to look at the past, but it also allows us to look forward and predict what might happen in the future. We are probably going to face another temperature change. It would be genetically very interesting to see how genes respond."

The sequencing will be done this year, with the final stages completed in China, but the scientists' data collection starts well before that - on their hands and knees in Antarctica.

Dr Millar and his team are in the Ross Sea region this month, surveying various sites for signs of ancient or relict Adelie penguin colonies, with logistical support from Antarctica New Zealand.
When they see something that looks promising, from a helicopter or while on the ground, they stop and start their "treasure hunting" or "penguin archaeology."

They find pebbles from old nests, guano, eggshells, feathers, bones and sometimes whole chicks, well preserved in the coldest and driest place on Earth.

Yvette Wharton, also of the University of Auckland, said it was "exactly like an archeological dig - you do it layer by layer. It's like uncovering treasure."

The Kiwi scientists' colleagues include Italian geomorphologists Dr Carlo Baroni and his partner, Dr Maria Cristina Salvatore, of the University of Pisa.

Dr Baroni is collecting ancient penguin samples from relict colonies and using dating techniques to reconstruct the glaciation history of different regions, as Adelie penguins nest only in ice-free areas during summer.

Ms Wharton said Adelie penguins were interesting to study when it came to climate change. Although many species responded to temperature increases by migrating, Adelie penguins had "nowhere to go."


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