“Vampire Squid From Hell” Genome Unlocks Secrets of Octopus and Squid Evolution
Deep-sea research has revealed the genome of the vampire squid (Vampyroteuthis infernalis – literally “vampire squid from hell”) holds crucial clues to the evolutionary history of octopuses and squids. A newly sequenced genome, published in iScience, demonstrates the vampire squid retains ancestral genetic characteristics lost in its more evolved relatives, positioning it as a “Rosetta Stone” for understanding cephalopod development.
The vampire squid’s genome is surprisingly large, several times bigger than those of typical squids and octopuses.Researchers discovered a massive 62 percent of its genetic material consists of repetitive elements – DNA sequences that repeat without contributing to coding – inflating the genome’s size.
A comparative analysis against genomes of decapodiforms (ten-armed squids and cuttlefish), octopodiforms (eight-armed octopuses), a nautilus, and other mollusks, including the unusual muddy argonaut (argonauta hians), revealed key insights. Despite being an eight-armed octopodiform,the vampire squid retains chromosomal structures characteristic of ten-armed decapodiforms. Further study of octopus genomes showed they also initially possessed a squid-like chromosomal structure,which later compacted and fused in a process called “fusion-with-mixing.”
“The vampire squid retains a genetic heritage that predates both [squid and octopus] lineages,” explains genomicist Emese Tóth of the University of Vienna. “It gives us a direct look into the earliest stages of cephalopod evolution.”
Researchers believe the early chromosomal mixing in octopuses may have driven their specialized adaptations, while the vampire squid’s chromosomes remained relatively stable despite its genome’s expansion.This unique genetic position makes the vampire squid invaluable for deciphering the complex evolutionary journey of cephalopods.
