Sunday, January 26, 2020

The Legendary Giant Squid

From Phys.org:
Today, important clues about the anatomy and evolution of the mysterious (Architeuthis dux) are revealed through publication of its full by a University of Copenhagen-led team that includes scientist Caroline Albertin of the Marine Biological Laboratory (MBL), Woods Hole. Giant are rarely sighted and have never been caught and kept alive, meaning their biology (even how they reproduce) is still largely a mystery. The genome sequence can provide important insight.

"In terms of their genes, we found the giant squid look a lot like other animals. This means we can study these truly bizarre animals to learn more about ourselves," says Albertin, who in 2015 led the team that sequenced the first genome of a cephalopod (the group that includes squid, octopus, cuttlefish, and nautilus). Led by Rute da Fonseca at University of Copenhagen, the team discovered that the giant squid genome is big: with an estimated 2.7 billion DNA base pairs, it's about 90 percent the size of the human genome. Albertin analyzed several ancient, well-known in the giant squid, drawing comparisons with the four other cephalopod species that have been sequenced and with the . She found that important developmental genes in almost all animals (Hox and Wnt) were present in single copies only in the giant squid genome. That means this gigantic, invertebrate creature—long a source of sea-monster lore—did NOT get so big through whole-genome duplication, a strategy that evolution took long ago to increase the size of vertebrates. So, knowing how this squid species got so giant awaits further probing of its genome.

"A genome is a first step for answering a lot of questions about the biology of these very weird animals," Albertin said, such as how they acquired the largest brain among the invertebrates, their sophisticated behaviors and agility, and their incredible skill at instantaneous camouflage. (Read more.)
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