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Newly Sequenced Giant Squid Genome Raises as Many Questions as It Answers – Gizmodo

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Photo: David McNew (Getty Images)

One the most intriguing and mysterious creatures on the planet—the giant squid—has finally had its genome fully sequenced. But while the genome is helping to explain many of its distinguishing features, including its large size and big brain, we still have much to learn about this near-mythical beast.

“A genome is a first step for answering a lot of questions about the biology of these very weird animals,” Caroline Albertin, a co-author of the new GigaScience study and a geneticist at the Marine Biological Laboratory at the University of Chicago, said in a press release.

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Indeed, little is known about the giant squid, due to its skittish nature and because it lives at such great depths. To date, not a single giant squid has been captured alive, so much of its biology remains a mystery. The only specimens that have been studied are carcasses that washed ashore or were accidentally hauled up by fisherman, and sightings in the wild have been limited to spooky, teasing glimpses taken by underwater cameras.

But now, in an important development, scientists have a fully sequenced giant squid genome.

Engraving of a giant squid stranded in 1877 on Trinity Bay, Newfoundland.
Image: Unknown/Wikimedia

“Having this giant squid genome is an important node in helping us understand what makes a cephalopod a cephalopod,” said Albertin. “And it also can help us understand how new and novel genes arise in evolution and development.”

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In total, the researchers identified approximately 2.7 billion DNA base pairs, which is around 90 percent the size of the human genome. There’s nothing particularly special about that size, especially considering that the axolotl genome is 10 times larger than the human genome. It’s going to take some time to fully understand and appreciate the intricacies of the giant squid’s genetic profile, but these preliminary results are already helping to explain some of its more remarkable features.

For example, Albertin and her colleagues identified a group of genes called reflectins, which are only known to exist in cephalopods. It’s a key finding, as color is an an essential element of camouflage.

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“Reflectins are a family of proteins that are only found in cephalopods, such as squid, cuttlefish, and octopus,” said Albertin in an email to Gizmodo. “They are involved in making the iridescence in the skin and the eyes, and most cephalopods, including the giant squid, have several of these genes.”

Because reflectins are only found in cephalopods, biologists can only study them in this group of animals, she said. Only a handful of cephalopods have been sequenced, “so the giant squid genome will be able to help us to understand the biology of this family of proteins,” explained Albertin.

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A giant squid measuring over 4 meters (13 feet) long.
Image: NASA

The scientists also identified genes responsible for growth and development, namely the Hox and Wnt genes. These genes might play a role in this animal’s gigantism, as individuals typically grow to between 9 and 13 meters in length (30 to 42 feet). That said, their size doesn’t appear to be the result of whole-genome duplication, an evolutionary growth strategy seen in large-bodied vertebrates.

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“Whole genome duplication has been described in a number of different groups of organisms,” Albertin told Gizmodo. “Some plants are famous for this, but vertebrates—animals with a backbone—also had a whole genome duplication that has been hypothesized to be important in their evolution. We don’t see evidence for whole genome duplication in any of the cephalopods examined thus far, including the giant squid.”

As to how the giant squid got to be so big remains an unanswered question.

Giant squids also have large brains, which we can only assume are as complex as those seen in other cephalopods. And indeed, the researchers identified well over 100 genes in a grouping known as protocadherins, which aren’t typically found in invertebrates.

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“For a long time, we thought that having a lot of protocadherins was only found in vertebrates, so we were really surprised when we found more than 160 of them in the octopus genome,” said Albertin, in reference to her 2015 paper on the subject. “We have found an expansion of protocadherins in the giant squid as well, which has the largest invertebrate brain. We don’t yet know what they are doing, but it could be a clue to how you make a complicated brain,” she told Gizmodo.

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Most of the genes seen in the giant squid are shared with other animals, like octopuses, snails, worms, flies, and humans, so this genome will now serve as an important reference point for scientists when comparing it to other cephalopods and animals, and for studying the giant squid’s unique features, said Albertin.

The scientific quest to learn more about giant squids continues. Thankfully, and as Albertin pointed out, marine biologists who study giant squids and related species are now equipped with a powerful new resource to help them learn more.

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Salty ponds found on Mars suggest stronger prospect of life on red planet, scientists say – CBC.ca

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A network of salty ponds may be gurgling beneath the South Pole on Mars, alongside a large underground lake, raising the prospect of tiny, swimming Martian life.

Italian scientists reported their findings Monday, two years after identifying what they believed to be a large buried lake. They widened their coverage area by a couple hundred miles, using even more data from a radar sounder on the European Space Agency’s Mars Express orbiter.

In the latest study appearing in the journal Nature Astronomy, the scientists provide further evidence of this salty underground lake, estimated to be 20 to 30 kilometres across and buried 1.5 kilometres beneath the icy surface.

Even more tantalizing, they’ve also identified three smaller bodies of water surrounding the lake. These ponds appear to be of various sizes and are separate from the main lake.

Roughly four billion years ago, Mars was warm and wet, like Earth. But the red planet eventually morphed into the barren, dry world it is today.

The research team led by Roma Tre University’s Sebastian Emanuel Lauro used a method similar to those used on Earth to detect buried lakes in the Antarctic and Canadian Arctic. They based their findings on more than 100 radar observations by Mars Express from 2010 to 2019; the spacecraft was launched in 2003.

All this potential water raises the possibility of microbial life on — or inside — Mars. High concentrations of salt are likely keeping the water from freezing at this frigid location, the scientists noted. The surface temperature at the South Pole is an estimated -113 degrees C and gets gradually warmer with depth.

These bodies of water are potentially interesting biologically and the researchers wrote that “future missions to Mars should target this region.” 

Earlier this year, a new computer model by NASA scientists lent further support to the theory that the ocean beneath the thick, icy crust of Jupiter’s moon Europa could be habitable.

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Salty lake, ponds may be gurgling beneath South Pole on Mars – CP24 Toronto's Breaking News

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Marcia Dunn, The Associated Press


Published Monday, September 28, 2020 7:46PM EDT

CAPE CANAVERAL, Fla. – A network of salty ponds may be gurgling beneath Mars’ South Pole alongside a large underground lake, raising the prospect of tiny, swimming Martian life.

Italian scientists reported their findings Monday, two years after identifying what they believed to be a large buried lake. They widened their coverage area by a couple hundred miles, using even more data from a radar sounder on the European Space Agency’s Mars Express orbiter.

In the latest study appearing in the journal Nature Astronomy, the scientists provide further evidence of this salty underground lake, estimated to be 12 miles to 18 miles (20 kilometres to 30 kilometres) across and buried 1 mile (1.5 kilometres) beneath the icy surface.

Even more tantalizing, they’ve also identified three smaller bodies of water surrounding the lake. These ponds appear to be of various sizes and are separate from the main lake.

Roughly 4 billion years ago, Mars was warm and wet, like Earth. But the red planet eventually morphed into the barren, dry world it remains today.

The research team led by Roma Tre University’s Sebastian Emanuel Lauro used a method similar to what’s been used on Earth to detect buried lakes in the Antarctic and Canadian Arctic. They based their findings on more than 100 radar observations by Mars Express from 2010 to 2019; the spacecraft was launched in 2003.

All this potential water raises the possibility of microbial life on – or inside – Mars. High concentrations of salt are likely keeping the water from freezing at this frigid location, the scientists noted. The surface temperature at the South Pole is an estimated minus 172 degrees Fahrenheit (minus 113 degrees Celsius), and gets gradually warmer with depth.

These bodies of water are potentially interesting biologically and “future missions to Mars should target this region,” the researchers wrote.

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Another look at possible under-ice lakes on Mars: They’re still there – Ars Technica

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In recent decades, we’ve become aware of lots of water on Earth that’s deep under ice. In some cases, we’ve watched this water nervously, as it’s deep underneath ice sheets, where it could lubricate the sheets’ slide into the sea. But we’ve also discovered lakes that have been trapped under ice near the poles, possibly for millions of years, raising the prospect that they could harbor ancient ecosystems.

Now, researchers are applying some of the same techniques that we’ve used to find those under-ice lakes to data from Mars. And the results support an earlier claim that there are bodies of water trapped under the polar ice of the red planet.

Spotting liquids from orbit

Mars clearly has extensive water locked away in the forum of ice, and some of it cycles through the atmosphere as orbital cycles make one pole or the other a bit warmer. But there’s not going to be pure liquid water on Mars—the temperatures just aren’t high enough for very long, and the atmospheric pressures are far too low to keep any liquid water from boiling off into the atmosphere.

Calculations suggest, however, that liquid water is possible on Mars—just not on the surface. With enough dissolved salts, a water-rich brine could remain liquid at the temperatures prevalent on Mars—even in the polar areas. And if it’s trapped under the Martian surface, there might be enough pressure to keep it liquid despite the thin atmosphere. That surface could be Martian soil, and people are thinking about that possibility. But the surface could also be one of the ice sheets we’ve spotted on Mars.

That possibility helped motivate the design of the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) on the Mars Express orbiter. MARSIS is a radar device that uses wavelengths that water ice is transparent to. As a result, most of the photons that come back to the instrument are reflected by the interface between ice and something else: the atmosphere, the underlying bedrock, and potentially any interface between the ice and a liquid brine underneath it.

And that’s what the original results, published in 2018, seemed to indicate. In an area called Ultimi Scopuli near Mars’ south pole. The researchers saw a bright reflection, distinct from the one caused by the underlying bedrock, at some specific locations under the ice. And they interpreted this as indicating a boundary between ice and some liquid brines.

Now with more data

Two things have changed since those earlier results were done. One is that Mars Express has continued to pass over Mars’ polar regions, generating even more data for analysis. The second is that studies of ice-covered lakes on Earth have also advanced, with new ones identified from orbit using similar data. So some of the team behind the original work decided it was time to revisit the ice sheets at Ultimi Scopuli.

The analysis involves looking at details of the photons reflected back to the MARSIS instrument from a 250 x 300 square kilometer area. One aspect of that is the basic reflectivity of the different layers that can be discerned from the data. Other aspects of the signal can tell us about how smooth the surface of the reflective boundaries are and whether the nature of the boundary changes suddenly.

For example, the transition from an ice-bedrock boundary to an ice-brine one would cause a sudden shift from a relatively weak, uneven signal to a brighter and smoother one.

The researchers generated separate maps of the intensity and the smoothness of the signal and found that the maps largely overlapped, giving them confidence that they were identifying real transitions in the surfaces. A separate measure of the material (called permittivity) showed that it was high in the same location.

Overall, the researchers found that the largest area that’s likely to have water under the ice as about 20 by 30 kilometers. And it’s separated by bedrock features from a number of similar but smaller bodies. Calling these bodies “lakes” is speculative, given that we have no idea how deep they are. But the data certainly is consistent with some sort of under-ice feature—even if we use the standards of detection that have been used for under-ice lakes on Earth.

How did that get there?

The obvious question following the assumption that these bodies are filled with a watery brine is how that much liquid ended up there. We know that these salty solutions can stay liquid at temperatures far below the freezing point. But the conditions on Mars are such that most of minimum temperatures for water to remain liquid are right at the edge of the possible conditions at the site of the polar ice sheets. So some people have suggested geological activity as a possible source of heat to keep things liquid.

That’s not necessarily as unlikely as it may sound. Some groups have proposed that some features indicate that there was magma on the surface of Mars as recently as recently as 2 million years ago. But the researchers here argue that if things are on the edge of working under current climate conditions, there’s no need to resort to anything exceptional.

Instead, they suggest that the sorts of salts we already know are present on Mars can absorb water vapor out of the thin Martian atmosphere. Once formed, these can remain liquid down to 150 Kelvin, when the local temperatures at Ultimi Scopuli are likely to be in the area of 160 Kelvin and increase with depth.

And if that’s true, there could be liquid in many more locations at Mars’ poles. Not all of them are as amenable to orbital imaging as Ultimi Scopuli, but it’s a safe bet that this team will try to find additional ones.

Nature Astronomy, 2020. DOI: 10.1038/s41550-020-1200-6 (About DOIs).

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