The genus of Giant Squid is sequenced for the first time
Scientists have published the complete genome sequence of the mysterious giant squid, which seems to indicate the high intelligence of the creature.
An international research team discovered that their genes are very similar to other animals – with a genome size not far behind that of humans.
The mysterious squid, Architeuthius dux, has eyes as large as signs and tentacles that grab prey from 10 meters away.
The average length is around 33 feet – about the size of an average school bus.
But these legendary creatures are notoriously elusive and observations are rare, making them difficult to study.
Now an international team of researchers has fully mapped the genome of the species to answer important evolutionary questions.
In this photo released by Tsunemi Kubodera in the National Science Museum of Japan, a giant squid attacking a bait squid is pulled up in December 2006 by its research team for the Ogasawara Islands, south of Tokyo.
These include how they have acquired the greatest brain of all invertebrates, as well as advanced behavior and agility, and the skill of immediate camouflage.
“A genome is a first step in answering many questions about the biology of these very rare animals,” said Caroline Albertin of the Marine Biological Laboratory (MBL) in Massachusetts.
‘Although cephalopods have many complex and extensive functions, they are thought to have evolved independently of the vertebrates.
“By comparing their genomes we can ask:” Are cephalopods and vertebrates built the same way or are they built differently? “
Albertin previously led a team that determined the sequence of the first genome of a cephalopod – the group that includes squid, octopus, squid and nautilus.
The team has extracted genomic DNA from a single giant squid using cetyl trimethyl ammonium bromide – a ammonium surfactant compound.
They discovered that the giant squid genome has an estimated 2.7 billion DNA base pairs – the associated chemical compounds on either side of DNA strands.
This is around 90 percent of the size of the human genome – we have around 3 billion.
Although genome size does not necessarily match intelligence, it may indicate functions such as cell division rate, body size, development rate, and even risk of extinction.
Albertin also identified more than 100 genes from the protocadherin family of proteins – usually not found in abundance in invertebrates – in the giant squid genome.
Protocadherins are thought to be important to connect a complicated brain correctly.
Artist’s impression of the cracking sea monster, probably inspired by the giant squid
The team was surprised to find more than 100 protocadherins in the octopus genome.
“That looked like a smoking gun to how to make a complicated brain,” she said. “And we have also found a similar extension of protocadherins in the giant squid.”
But how did the creature become that big? It is a question that, according to the team, needs further investigation.
But they have excluded a possible option: duplication of the entire genome – an evolutionary strategy that was established millions of years ago for species to increase their size.
The giant squid genome revealed only a few copies of major developmental genes used in genome duplication – called Hox and Wnt – that are present in almost all animals.
The lack of these two developmental genes the team suggested that the giant invertebrates did not use the entire genome duplication to increase its size as it evolved, but something else.
The giant squid has long been a subject of horror lore. In this original illustration from Jules Verne’s 20,000 Leagues Under the Sea, the squid grabs a helpless sailor
Albertin also analyzed a gene family that has hitherto been unique to cephalopods, called reflectins, that encode a protein involved in iridescence – the amazing ability to change color from different angles.
“Color is an important part of camouflage, so we try to understand what this gene family does and how it works,” Albertin said.
Giant squid is rarely observed and has never been caught and kept alive, which means that details of their biological makeup have remained a mystery.
“Having this giant squid genome is an important node to help us understand what makes a cephalopod a cephalopod,” said Albertin
“And it can also help us understand how new and new genes arise in evolution and development.”
The giant squid of the Architeuthis Gender was first described by researchers in 1857.
Despite spreading around the globe, except in the high Arctic and Antarctic waters, the creature is notoriously elusive, although it was first caught in American waters last year.
The new study, led by a team at the University of Copenhagen in Denmark, has been published in the journal GigaScience.
WHAT IS THE GIANT SQUID?
According to Smithsonian, giant squids would live in all oceans of the world, though not so much in the tropical and polar regions.
They live deep below the surface in “ink black black, icy cold water” from 500 meters to 1000 meters deep.
And they are extremely elusive.
Until 2006, a giant squid had never been filmed alive, and much about what is known about them is based on washed up carcasses.
The largest ever recorded, including the tentacles, is no less than 13 meters and scientists suspect that the creatures can grow up to 20 meters.
Their eyes are as big as plates, each about 30 centimeters wide.