The octopus is a marvel of the ocean. With their eight versatile, sucker-lined tentacles, their huge intelligence, and the flexibility to squeeze themselves into tight areas, these cephalopods have lengthy captured our marvel. Whereas the octopus nonetheless holds many secrets and techniques, a brand new examine helps reply the long-held query of how these creatures decide their intercourse. 

Courting again 480 million years, octopuses have one of many oldest identified intercourse chromosomes, in response to a brand new examine revealed in Present Biology. The examine unveils that octopuses decide their intercourse via chromosomes, which helps researchers discover extra of the octopus’ genetic historical past. 

Figuring out Intercourse Chromosomes

Most mammals, together with people, decide intercourse via chromosomes. Nonetheless, that’s not the case for all animals. In different animals, similar to sea turtles, the temperature of the sand that incubates the eggs determines the intercourse of the offspring. Sure fish have a gene that determines intercourse, which isn’t a full chromosome. So, when it got here to the octopus, it was unclear how intercourse was decided. 

“Cephalopods are already such attention-grabbing creatures, and there are such a lot of issues we’re nonetheless studying about them, particularly in neuroscience,” stated Gabby Coffing, a doctoral pupil on the College of Oregon working within the lab of biologist Andrew Kern, in a press launch. “That is simply exhibiting yet one more attention-grabbing factor about them: They’ve actually historical intercourse chromosomes.”

Learn Extra: Octopuses Accomplice with Fish to Hunt, and Will Slap the Fish That Slacks Off

Half a Chromosome 

The group was sequencing the DNA of a feminine California two-spot octopus once they seen a chromosome containing solely half the quantity of genetic materials, and it seemed totally different in comparison with the male two-spot octopus DNA that had been sequenced.

“This specific chromosome had half the quantity of sequencing information, which indicated there was just one copy,” stated Coffing in a press launch. “Then, as we explored that extra, we reached the conclusion that we will need to have stumbled upon a intercourse chromosome.” 

To substantiate the findings, the researchers checked out previous octopus genomic information and famous that they weren’t clearly labeled as a male or feminine. Nonetheless, they did discover proof of one other half-chromosome in a special species of octopus. The identical factor was present in squid genes, though squids and octopuses diverged evolutionarily between 248 million years and 455 million years in the past.

Lastly, researchers famous that the nautilus, a mollusk that additionally diverged from the octopus round 480 million years in the past, additionally had the same chromosome. This means that any such intercourse dedication has been within the species for hundreds of thousands of years. 

This, stated Andrew Kern, head of the lab Coffing and the analysis group, is uncommon for intercourse chromosomes. These chromosomes impression copy and infrequently change and evolve quickly over time. Nonetheless, it seems that for octopuses and different cephalopods, that is the strategy they’ve caught with. 

A Doable New System

For people, we use the XX/XY system to determine the feminine and male chromosomes — XX is feminine and XY is male. Nonetheless, the analysis group believes that octopuses could relate to the system used for butterflies and birds, which is ZZ/ZW — males are ZZ and females are ZW. 

The group has but to determine a “W” chromosome in any octopus. It’s potential that octopuses may have a special system altogether the place males are ZZ and females are simply Z. In accordance with Coffing, the chromosome system has not but been decided. However with these findings, Coffing and the remainder of the group are one other step nearer to unveiling extra of the octopus’ mysteries.

Learn Extra: Are Octopus Sensible? A Look Contained in the Mind of an Octopus

Article Sources

Our writers at Discovermagazine.com use peer-reviewed research and high-quality sources for our articles, and our editors assessment for scientific accuracy and editorial requirements. Assessment the sources used beneath for this text:

• Present Biology. Cephalopod intercourse dedication and its historical evolutionary origin

A graduate of UW-Whitewater, Monica Cull wrote for a number of organizations, together with one which targeted on bees and the pure world, earlier than coming to Uncover Journal. Her present work additionally seems on her journey weblog and Frequent State Journal. Her love of science got here from watching PBS reveals as a child along with her mother and spending an excessive amount of time binging Physician Who.