Scientists Analyze Penguin DNA And Find Something Incredible

Penguins are no strangers to climate change. Their life history has been shaped by fluctuations in temperature, and their bodies are highly specialized for some of the most extreme conditions on Earth.

However, scientists fear the penguin’s evolutionary path may have stalled, thanks to the lowest evolutionary rate ever detected in birds.

An international team of researchers has just published one of the most comprehensive studies on penguin evolution to date, which is the first to integrate data from living and fossil penguin species.

The research reveals a general chaotic penguin life history, with three-quarters of all known penguin species – now represented only by fossils – already extinct.

“Over 60 million years, this iconic bird has evolved into a highly specialized marine predator, and is now well-adapted in some of the most extreme environments on Earth,” the authors wrote.

“However, as their evolutionary history reveals, they now stand as guardians highlighting the vulnerability of cold-adapted fauna in a rapidly warming world.”

On land, penguins can look a bit goofy, with awkward wags and seemingly useless wings. But underwater, their bodies turn into hydrodynamic torpedoes that would make fleeing fish wish they could fly.

Penguins lost their ability to fly 60 million years ago, before the formation of the polar ice caps, in favor of wing-driven diving.

Fossil and genomic data show the unique features that allowed penguins’ aquatic lifestyles to emerge early in their existence as a group, with rates of evolutionary change generally tending to decline over time.

Scientists think the penguins came from the Gondwanan micro-continent called Zealandia, which is now mostly submerged under the sea.

The paper suggests the ancestor of modern penguins – the crown penguin – appeared about 14 million years ago, 10 million years after genetic analysis hinted.

This particular period will coincide with a moment of global cooling called the Middle Miocene climate transition. Living penguins, however, split into separate genetic groups in the last 3 million years.

Penguins spread throughout Zealandia before spreading to South America and Antarctica several times, with later groups likely to hitch a ride in the Antarctic Arctic Circle.

Scientists found that nearly every penguin species experienced a period of physical isolation during the Last Glacial Period.

Their contact with other penguins was limited during this time, as the groups were forced to live in more fragmented habitat areas further north, where they could still find food and shelter.

As a result, the DNA pool of each group becomes narrower, pushing the species further apart genetically.

In the next period of warming, they moved back toward the poles, and several groups, now much more genetically distinct, crossed paths once again.

The way certain groups of penguins experience these significant climatic events offers insight into how they can cope with human-caused climate change.

The groups that increase in number as warming occurs have several characteristics: They migrate, and forage offshore. The researchers think these features allow them to better respond to climate change, particularly the ability to see prey farther away and move to lower latitudes.

The diminished ones, on the other hand, live in one particular place, and look for food closer to the coast: a not-so-favorable lifestyle when conditions ‘at home’ change drastically.

But penguins’ ability to change may be limited by more than lifestyle – it seems to be ingrained in their genes.

It turns out that penguins have the lowest evolutionary rate ever detected in a bird species, along with their sister order, Procellariiformes, which includes birds such as petrels and albatrosses.

The researchers compared 17 different bird orders overall, using several genetic markers that are closely related to the rate of evolutionary change.

They noticed that waterbirds generally had a slower evolutionary rate than their terrestrial relatives, so they thought the adoption of an aquatic lifestyle might go hand in hand with a low evolutionary rate. They also think that the evolutionary rate of birds is lower in colder climates.

The order Pelecaniformes, which includes seafaring birds such as pelicans and cormorants, is third for the lowest evolutionary rate, and waterfowl (order Anseriformes) have much lower rates than earth-living birds such as turkeys, chickens, and quail (order Anseriformes). Galliformes).

The researchers noted that ancestral crown penguins evolved at a faster rate than living penguins, but even then, this was slower than that of other birds.

Half of all living penguin species are endangered or vulnerable, and scientists say their slow evolutionary rate and specialized lifestyle could send penguins into a dead end.

“The current rate of warming combined with limited protection in the Southern Ocean will likely far exceed the adaptive capacity of penguins,” they wrote.

“The risk of future collapse is always present as penguin populations in the Southern Hemisphere face rapid anthropogenic climate change.”

This research was published in Nature Communication.

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