Penguin Genome Shows How They Adapt to Climate Change

Researchers have sequenced the genome of two penguin species for the first time, shedding light on how these birds have dealt with their cold and hostile Antarctic environment in the past, as well as how they might adapt to climate change in the future.

Adélie and emperor penguins are able to deal with all sorts of harsh weather, including extremely low temperatures, high winds, and profound changes in daylight. That's all thanks to complex biological systems that help them regulate temperature and store energy for long-term fasting. And by analyzing penguin DNA and comparing them with other bird species, researchers were able to delve deeper into these mechanisms, revealing the genetic basis of their adaptations.

The findings were published in the journal GigaScience.

For example, both Adélie and emperor penguins were found to have expanded genes related to beta-keratin proteins, which make up 90 percent of feathers, with an impressive 13 genes pertaining to one particular type of beta-keratin alone - the highest of any other bird genome. According to the study, this ensures that their feathers are short, stiff and densely packed to minimize heat loss amidst the cold Antarctic.

Fat storage is also critical for these birds, which must be able to withstand freezing temperatures and long fasting periods - up to four months in the case of emperor penguins. Researchers found eight genes involved in lipid metabolism in the Adélie penguin and three in the emperor penguin, an adaptation that proved to be beneficial.

In addition, about 17 genes related to the penguins' forelimbs were identified that boasted some unique changes allowing for wing-propelled diving in the water. One specific gene, called EVC2, showed a larger number of genetic changes compared to other birds.

"Penguins show distinct evolution relative to other bird species. They can't fly, have specialized skin and feathers, degenerated wings, and live in a cold environment in which most other birds could not survive," researcher Guojie Zhang said in a press release.

So how does all this relate to climate change? Well, the historical gene record of these resilient birds showed that when the climate became warmer about 150,000 years ago, Adélie penguin numbers dramatically rose, but later declined by 40 percent some 60,000 years ago during a cold and dry glacial period. In contrast, the emperor penguin population remained stable, suggesting that they were better adapted to glacial conditions.

"These different patterns in historical population change also suggest that future climate change may have impacts on the two penguin species," co-author Cai Li added.

It goes to show that not all penguins are one in the same, and that Adélie penguins in particular could suffer more from a warming world due to climate change.

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