One of the earliest creatures, the comb jelly, has the ability to merge with another.

It was a warm summer night in 2023 when Kei Jokura, a marine biologist, entered the marine biology lab at Woods Hole Oceanographic Institution in Massachusetts. He was carrying a beaker containing a mysterious blob, his excitement palpable. Just moments before, he had been on the first floor where tanks filled with gelatinous comb jellies were housed.

This particular blob was different from the others he had seen. It seemed to be a fusion of two jellies, larger than any other he had encountered before. Jokura, who was a postdoctoral researcher at the University of Exeter in the UK at the time, couldn't believe his eyes. He recalled, "I was in complete awe. How could two jellies merge and still swim and move as one?"

Mariana Rodriguez-Santiago, a postdoctoral researcher at Colorado State University, was also in the lab that night, working on her own project. When she saw Jokura's discovery, she was equally amazed. She grabbed a pipette and poked one of the jellies, causing it to squirm. To her surprise, the other jelly, seemingly attached to the first, also squirmed. This raised questions for the researchers: could they feel the same thing? Were they one individual or two? How could they be separated?

Over the next few weeks, Rodriguez-Santiago assisted Jokura in combining multiple pairs of the comb jellies, scientifically known as Mnemiopsis leidyi. Their findings, published in the journal Current Biology on October 7, 2023, revealed that not only could two jellies fuse their bodies, but their nervous and digestive systems would also fuse. It was as if two became one.

Jokura, now a postdoctoral researcher at Japan's National Institute for Basic Biology, stated, "The fusion phenomenon has sparked many intriguing questions, such as which genes are involved in fusion, how neural signaling is affected, and what defines 'self' and 'nonself'." He believes that exploring these themes could challenge our fundamental understanding of biology.

Comb jellies can be found in coastal waters and the deep ocean all around the world. Despite their similar appearance to jellyfish, they do not have stinging abilities and belong to a different phylum called Ctenophora, which means "comb-bearers" in Greek. They are named for their combs, rows of cilia that they use to navigate through the water.

According to Rodriguez-Santiago, who coauthored the study, ctenophores are believed to be one of the oldest animals on Earth and may even be a sister species to all other animals on the tree of life. She stated, "This makes them a unique subject for studying fundamental aspects of nervous system function."

Pawel Burkhardt, an evolutionary biologist and researcher at the University of Bergen in Norway, who was not involved in the study, commented, "The two recent papers highlight that ctenophores have the ability to adapt quickly to changing environments and have more flexible developmental programs compared to other animals."

The fusion phenomenon may also serve as a survival mechanism for ctenophores. Jokura's paper suggests that they lack the protective allorecognition mechanism found in other organisms, which allows them to distinguish between their own cells and tissues and those of another organism. In humans, allorecognition is what causes organ rejection in transplant surgeries.

Jokura originally stumbled upon this discovery while studying how M. leidyi responds to light. He found two injured specimens that had become conjoined and became curious to recreate the phenomenon. With Rodriguez-Santiago's help, they began experimenting by slicing off parts of several jellies and placing them together in petri dishes overnight.

To their surprise, nine out of ten pairs fused successfully, resulting in animals with two sensory organs and two sets of anal openings, compared to typical jellies that have only one of each. The fusion process happened much quicker than expected, with the jellies' rhythmic movements synchronizing within two hours.

Further imaging showed that the fusion also occurred in the digestive systems, meaning the animals could share food and expel waste through both anuses. Rodriguez-Santiago found this particularly fascinating as it challenged the concept of "self" and "other" in these creatures.

Burkhardt believes that these findings could lead to a better understanding of when allorecognition evolved and shed light on how simple nervous systems form and process information. As for Jokura, he hopes to continue studying the jellies' fused nervous systems and explore the concept of a shared consciousness.

[This article has been trending online recently and has been generated with AI. Your feed is customized.]
[Generative AI is experimental.]