Giant squids of the genus Architeutis are one of the largest invertebrate creatures, which, according to official data, can reach about 8-10 meters in length, and twice as much according to unofficial ones.
Pictures of live squids were first obtained by Japanese researchers in 2004, before that scientists had ideas about giant squids only from their remains found in the stomachs of sperm whales or washed ashore.
Until now, not a single giant squid fell into the hands of scientists, which is associated not only with the fact that these creatures live mainly at great depths, but that that they rarely swim to the surface, as they sperm whale’s favorite treat.
The genome of giant squid was analyzed by a team of researchers from the University of Copenhagen (Denmark), as well as researchers from the Marine Biological Laboratory of the State of Massachusetts under the leadership of Caroline Albertin. In total, this group sorted the genomes of several cephalopods at once, including octopus, cuttlefish and nautilus mollusk.
DNA samples of a giant squid were taken from a frozen piece of flesh of this creature, found many years ago on the ocean and preserved in one of the laboratories.
Researchers first found that the size of the giant squid genome is not that far behind the human genome. The giant squid had about 2.7 billion complementary pairs of DNA, which is about 90% of the human genome.
Although the size of the genome is not necessarily related to the creature’s complexity and intellectual development, more than a hundred giant squid genes have been linked to a family of specific protocadherin proteins that are responsible for complex brain structure.
According to Caroline Albertin, as a rule, these proteins are found in very little (or not at all) in invertebrates, and the presence of more than 100 protocadherins in the giant squid genome can be compared to the finding of a “smoking gun”, because this directly indicates that these creatures are very smart.
By the way, in the octopus genome in 2015, the same proteins were also found in approximately the same amount.
Other unusual finds include a unique set of genes responsible for the growth and development of giant squid, which were not in the genome of octopus, cuttlefish and nautilus. This probably explains why giant squids grow so huge.
The results of this curious study were published in the scientific journal GigaScience.