Was penguin evolution driven by a cooling Antarctic?

By Sankar Subramanian, Griffith University

This article was originally published at The Conversation. Read the original article. 

Some like it hot: Galapagos penguins
enjoy a tropical climate. ms akr

Penguins are a remarkable group of flightless birds. We tend to think of them as Antarctic birds, but they actually inhabit an extremely diverse range of habitats from subzero Antarctic coastline to the tropical Galapagos Islands. Research we published on 13 November in the Biology Letters gives us new insight into how this diverse group evolved.

There are now 18 recognised species of penguins. All live predominantly in the Southern Hemisphere (those Galapagos penguins being the exception), in a wide range of climates.

Ancient penguin DNA sheds light on evolutionary change

Adelie penguin at Palmer Station.
Photo credit: Johnny Shaw.
Some rights reserved.

AUSTRALIA - By recovering DNA sequences from ancient sub-fossil bones of Adelie penguins and comparing them to DNA from today's penguins, scientists are building a picture of evolutionary change that is much faster than previously estimated.

The research, undertaken by Griffith University scientists in Antarctica and at the university's campus in Brisbane, Queensland, featured on the 26 May episode of the ABC programme Catalyst.

In the episode, Catalyst presenter Dr Paul Willis collected specimens from recently dead Adelie penguins (their feet) in the Antarctic Peninsula and took them back to the university. There, DNA from the feet was compared to ancient DNA sequences of varying ages up to 44,000 years old.

"The ancient bones underlie existing and abandoned breeding colonies from around the Antarctic continent and are one of the richest sources of ancient DNA yet discovered," lead researcher Professor David Lambert told Griffith University News.

"In comparing these sequences we are able to build up a picture of the speed of DNA change over time."

In the program, Professor Lambert said, "Results from Adelie penguin studies haven't confirmed a number of previous studies ... those rates have been very high, much higher than previous estimates."

The Griffith team will be applying the DNA comparison technique to other animals to see if they also have higher rates of DNA change.

Professor Lambert said that these molecular rates are very important for use within a range of science disciplines ranging from forensics to evolutionary biology.

Sources
Griffith research with penguin advances understanding of DNA by Louise Durack, 24 May 2011, Griffith University News
Catalyst: Penguin DNA, 26 May 2011, ABC