Becoming One

Scientists recently discovered that an inconspicuous marine animal is capable of some Frankenstein-esque feats.

Meet the comb jelly, an invertebrate that resembles a jellyfish, but differs greatly from it – the former for example lacks stinging tentacles.

These invertebrates can grow up to five inches in length and propel themselves with eight rows of comb-like cilia – tiny hair-like structures – which create a rainbow effect as light scatters off their movement.

Now, a new study has found that individuals of the comb jelly species Mnemiopsis leidyi can fuse together to become a single organism.

Biologist Kei Jokura and his team first noticed this odd phenomenon in the lab – they observed one peculiar comb jelly that was bigger than the rest with two heads, two mouths and two anuses.

The kicker was that it was behaving as one individual instead of two, prompting the researchers to wonder whether this was an anomaly.

“So we did some Frankenstein pilot experiments,” co-author Mariana Rodriguez-Santiago told NPR.

For their tests, they took partially sliced comb jellies and placed them next to each other in the tank. They then watched as the injured individuals fused together 90 percent of the time and survived for at least three weeks.

The team reported that about 95 percent of the fused animal’s muscle contractions were fully synchronous.

This fusion was also present in their digestive tract: Researchers fed them brine shrimp packed with a fluorescent dye and noticed how the food particles moved through the gut of both jellies – eventually expelled from both anuses, but not at the same time.

“Our findings suggest that ctenophores may lack a system for allorecognition, which is the ability to distinguish between self and others,” explained Jokura in a statement. “Additionally, the data implies that two separate individuals can rapidly merge their nervous systems and share action potentials.”

The paper marks the first time scientists have documented the behavior, adding that future studies could fill gaps in understanding and potentially impact regenerative research.

For example, the comb jellies’ ability to rapidly regenerate and heal could offer insights for humans, such as speeding up organ transplant recovery and regaining control over transplanted limbs.