Gene study reveals penguin evolution to marine environments

BEIJING, Aug. 4 (Xinhua) -- A China-led research team has completed a genetic study on penguin species to understand how the tuxedo-clad bird evolved from their flying ancestors 60 million years ago into the excellent swimmers we know today.

Published in the journal Nature Communications, the study analyzed the genomes of all living and extinct penguin species, alongside their fossil data, providing new insights into the genetic basis for penguin evolution and its adaptation to marine environments.

The study confirmed that ancient penguins originated in Zealandia, a submerged continent in the South Pacific Ocean, about 65 million years ago. The ancestor of penguins appeared about 14 million years ago, after which global climate changes drove the penguin evolution and contributed to the formation of new species, said lead researcher Zhang Guojie, from Kunming Institute of Zoology of the Chinese Academy of Sciences.

It also identified a suite of genes that allow the bird to live both on land and in water, including those related to heat regulation, blood oxygenation, diving ability, underwater vision, diet, and body size.

Over 60 million years, penguins have gradually become smaller in size, and their beaks and limbs have evolved to be more suitable for marine environments, according to Zhang.

Researchers in the study also found that penguins at high latitudes, such as emperor penguins, had significantly faster evolutionary rates than those at low latitudes, suggesting that the extreme Antarctic environment put greater environmental stress on penguins, and to some extent, facilitated the adaptation of the high-latitude species to extreme environments.

These findings help to understand which genes underpin the penguin adaptations to marine and extreme cold environments on Earth, Zhang said.

"They also demonstrated that penguins have adapted to an ever-changing world during the past 60 million years, and people can be optimistic on how the species respond to future climate change scenarios."