Evolutionary discoveries in penguin study

Evolutionary discoveries in penguin study

As the great Antarctic icebergs have broken off and shifted throughout the centuries it now seems their movement caused more lasting change than has been understood.

Massey University scientists now report the movement of the icebergs has caused dramatic environmental changes that have contributed to microevolution among colonies of Adelie penguins.

The research by the team in New Zealand is the cover story in the latest edition of a prestigious American based science journal, PNAS, appeared in the latest issues of National Geographic and is making headlines world wide.

PNAS is the proceedings of the National Academy of Sciences of the United States of America. Its contents are closely followed by the world science community.

The research team is led by evolution biologist, Distinguished Professor David Lambert and, based at the Allan Wilson Centre for Molecular Ecology on the Auckland campus. Microevolution involves any genetic changes within a species level, such as bacteria acquiring antibiotic resistance. Detecting such changes over a long period can be difficult, says Profesor Lambert.

Professor Lambert has studied Adelie penguins for some years. A number of unique characteristics made the penguins ideal for evolution focused research.

The penguins have dense nesting colonies and the adult birds commonly return to the same birth site, giving a stable population of the same birds. Beneath the colonies there are well preserved layers of ancestor bird remains from which the research team have been able to take samples.

The researchers carried out DNA sequencing from samples taken from both the 6,000 year old remains and from the modern colony.

Significant changes were observed in the frequency of genes between these two groups. Becauuse the sequences studied were from noncoding DNA regions, the microevolution was not likely to have arisen from natural selection.

The scientists believe gene mixing could be the cause of microevolution in the penguins. The gene mixing could have come about when colonies were scattered, through sudden disruption of their environment by some outside factor such as iceberg movement.

In 2001 a ‘mega-iceberg’ broke off from the Ross ice shelf and drifted near many nesting colonies, blocking the swim paths of penguins and forcing them to migrate to more accessible colonies.

Mega-icebergs on the move have been a repeated historical phenomenon. Their shifts are likely to have precipitated penguin evolution by displacing the birds, says Professor Lambert’s team.

ENDS

See... Full paper (PDF)

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