An animal able to regenerate all of its organs even when it is dissected into three parts

A surprising discovery in the Gulf of Eilat


Research News


An extraordinary discovery in the Gulf of Eilat: Researchers from Tel Aviv University have discovered a species of ascidian, a marine animal commonly found in the Gulf of Eilat, capable of regenerating all of its organs – even if it is dissected into three fragments. The study was led by Prof. Noa Shenkar, Prof. Dorothee Huchon-Pupko, and Tal Gordon of Tel Aviv University’s School of Zoology at the George S. Wise Faculty of Life Sciences and the Steinhardt Museum of Natural History. The findings of this surprising discovery were published in the leading journal Frontiers in Cell and Developmental Biology.

“It is an astounding discovery, as this is an animal that belongs to the Phylum Chordata – animals with a dorsal cord – which also includes us humans,” explains Prof. Noa Shenkar. “The ability to regenerate organs is common in the animal kingdom, and even among chordates you can find animals that regenerate organs, like the gecko who is able to grow a new tail. But not entire body systems. Here we found a chordate that can regenerate all of its organs even if it is separated into three pieces, with each piece knowing exactly how to regain functioning of all its missing body systems within a short period of time.”

There are hundreds of species of ascidians, and they are found in all of the world’s oceans and seas. Anyone who has ever opened their eyes underwater has seen ascidians without knowing it, as they often camouflage themselves as lumps on rocks and are therefore difficult to discern. The animal that is the subject of this new study is an ascidian from the species Polycarpa mytiligera, which is very common in the coral reefs of Eilat.

“By all accounts, the ascidian is a simple organism, with two openings in its body: an entry and an exit,” says Tal Gordon, whose doctoral dissertation included this new research. “Inside the body there is a central organ that resembles a pasta strainer. The ascidian sucks in water through the body’s entry point, the strainer filters the food particles that remain in the body, and the clean water exits through the exit point. Among invertebrates, they are considered to be the closest to humans from an evolutionary point of view.”

Ascidians are famous for their regenerative ability, but until now these abilities have been identified mainly in asexual reproduction. Never before has such a high regenerative capacity been detected in a chordate animal that reproduces only by sexual reproduction.

“There are species of ascidians that perform simple regeneration in order to reproduce,” Gordon says. “These are species with a colonial lifestyle, with many identical individuals connected to one another. They replicate themselves in order to grow. In contrast, the ascidian from Eilat, Polycarpa mytiligera, is an organism with a solitary lifestyle, without the capacity for asexual reproduction, similar to humans. In previous studies we showed that this species is able to regenerate its digestive system and its points of entrance and exit within a few days. But then we wanted to see if it is capable of renewing all of its body systems. We took a few individual ascidians from Eilat and dissected them into two parts, which were able to replenish the removed sections without any problem. In a subsequent experiment, we dissected several dozen ascidians into three fragments, leaving a part of the body without a nerve center, heart, and part of the digestive system. And contrary to our expectations, not only did each part survive the dissection on its own, all of the organs were regenerated in each of the three sections. Instead of one ascidian, there were now three. This is very astonishing. Never before has such regenerative capacity been discovered among a solitary species that reproduces sexually, anywhere in the world.”

Prof. Shenkar concludes: “Since the dawn of humanity, humans have been fascinated by the ability to regenerate damaged or missing organs. Regeneration is a wonderful ability that we have, to a very limited extent, and we would like to understand how it works in order to try and apply it within our own bodies. Anyone snorkeling in the Gulf of Eilat can find this intriguing ascidian, who may be able to help us comprehend processes of tissue renewal that can help the human race.”


From EurekAlert!

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May 7, 2021 2:19 am

Polycarpa mytiligera, is an organism with a solitary lifestyle, without the capacity for asexual reproduction, similar to humans

humans have been fascinated by the ability to regenerate damaged or missing organs.

Well, I would eat, inject or have sex with Polycarpa mytiligera
… if it sorted my collapsing joints !!

William Capron
Reply to  saveenergy
May 7, 2021 6:58 am

What it is really similar to is Liberals, or maybe Libera policies; they can’t be killed and will rise up from their presumed death to bite us in the butt. Well, at least we now know there is an animal model for this.

Reply to  saveenergy
May 8, 2021 8:48 am

Already here (and has been for decades). An American soldier from Iraq with a severe leg injury from an IED regained 110% (from 30%) functionality with usage of regeneration from porcine extracellular matrix. Nerves, blood vessels, muscle etc all restored. This was in 2011 but will never see routine usage because it’s a “cheap fix” that won’t allow the corrupt NIH/CDC/FDA/AMA pharma to make billions. There are many other “cheap” options for other areas of medicine that will similarly remain unapproved for the same evil reasons. So if you have a med problem do thorough research and you may find a better solution elsewhere.

May 7, 2021 2:20 am

Fascinating! It shows how little we really know about complex biological processes, and other complex issues such as our chaotic, non-linear, climate.

May 7, 2021 2:24 am

All the information is in the genes. It just has to be turned on. Of course. Might be difficult to regrow memories.

Willem Jan Goossen
Reply to  Gerkenstein
May 7, 2021 4:02 am

MMmmmm….., to quote Bob (the Blob from Monsters vs Aliens), it turned out you don´t need brains to be succesfull. Yust look at some of the videos on Youtube LOL

Reply to  Gerkenstein
May 7, 2021 6:55 am

he DNA only supplies the coding for proteins, the body plans are found else where. some years back they took a fat cell stressed it greatly and it become a stem cell and Dolly a female sheep was produced. Some have suggested that the body plan data is some how coded in the cellular wall. What a stem cell becomes, has so much to do with location. so much we do not know.

John Tillman
Reply to  ROY
May 7, 2021 7:24 am

Body plan genes and the proteins they encode:

May 7, 2021 3:56 am

Regeneration is a wonderful ability that we have, to a very limited extent, and we would like to understand how it works in order to try and apply it within our own bodies.

At first I thought, “What?!?” But after another sip of coffee, I realized humans do regenerate to an extent; skin, bones, and other bits and bobs. We repair ourselves to an extent, but not like these little critters.

We’re learning a bit about cloning and regrowing some tissue. I think they are having some success with ears. But then that’s it. That’s all you get is a bit of an ear.

The amazing part to me was that the 3 parts of this ascidian regenerated all of the cut away, missing parts. You wound up with 3 new ascidians.

That opened my eyes a good bit wider than any cup of coffee. Amazing! We humans are pikers by comparison, just regenerating a bit of skin over a cut.
This has the makings of a ‘Dr. Evil’ type story where an ascidian-type army is created by some madman. If you blow up one of the soldiers, all the parts regrow what they need to form another soldier. Trying to kill the soldiers just makes more of the soldiers.

Timo, not that one
Reply to  H.R.
May 7, 2021 9:56 am

The Sorcerer’s Apprentice knows how to do this with corn brooms.

John Tillman
Reply to  H.R.
May 7, 2021 10:30 am

Max of three parts. And humans need brains, so maybe only one regenerant per KIA soldier.

Reply to  John Tillman
May 7, 2021 11:03 am

Don’t underestimate Evil Geniuses, John.

I’m not too worried, because when the Super Secret Agent comes to k!ll the Evil Genius and gets caught, the Evil Genius always talks w-a-a-y too long instead of just k!lling the agent. That allows the Super Secret Agent to cut loose and see to it the Evil Genius gets k!lled in his own trap.

So, I’m not particularly worried.
What does worry me is the Evil Imbeciles that keep getting elected. Now there’s where the real concern should be.

John Tillman
Reply to  H.R.
May 7, 2021 3:43 pm

So right you are!

Never underestimate your enemy, whether he/she be an Evil Genius or a climate alarmist.

John Tillman
May 7, 2021 4:02 am

Genetic analysis shows that Class Ascidiacea isn’t a valid clade. It’s paraphyletic, composed of one order and two families from another order, but not that order’s other families.

The order and family to which Genus Polycarpa belongs are however monophyletic.

The higher clade to which these sea squirts belong, Subphylum Tunicata, is either the sister group to vertebrates, sharing a common ancestor in Phylum Chordata, or we descend from a tunicate. Sea squirt larvae have notochords, which evolved into the vertebrate backbone.

Reply to  John Tillman
May 7, 2021 4:13 am

If we are descended from Sea squirts,
… that explains incontinence !

Last edited 1 year ago by 1saveenergy
John Tillman
Reply to  saveenergy
May 7, 2021 4:19 am

And a lot else!

Even way back in the Cambrian, when I was a freshman biology student, vertebrates were thought to be descended from tunicates. Their free swimming larvae look like cartoons of vertebrates.

Now both fossils and genetics support this hypothesis. If we’re not descended from a true sea squirt, then we and they share a very tunicate-like common ancestor.

John Tillman
Reply to  John Tillman
May 7, 2021 7:26 am
Reply to  John Tillman
May 7, 2021 7:56 am

That’s OLD.

John Tillman
Reply to  glen
May 7, 2021 10:25 am

It just feels like 540 million years when I listen to Mikey Mann.

May 7, 2021 4:20 am

Well, very much on-time comes the relevant tool to switch on/off all our sleeping genes:
May be, we do carry the Ascidianian genes?

George V
May 7, 2021 4:31 am

“..the ascidian is a simple organism, with two openings in its body: an entry and an exit,…they are considered to be the closest to humans from an evolutionary point of view.”

Well, that explains a lot about the behavior and thought processes of vast numbers of the human race.

Reply to  George V
May 7, 2021 5:02 am

One supposes that the ends could be interchangeable, particularly among politicians.

John Tillman
Reply to  Scissor
May 7, 2021 5:30 am

Chordates are deuterstomes, in which the anus forms before the mouth during embryonic development.

Reply to  John Tillman
May 7, 2021 9:05 am

Apparently their embryo-genesis yields 2 poles. One each with stem cells.

The stem cells partition into domains for different functions; with layers of histogenic cells. Super-imposed on the stem cell domains will be physiological zones.

In the different stem cell zones there will be different rates of cell division. I surmise there will be 3 zones.

The initial stem cells would reside in the central zone & have the slowest cell division rate. There would be a lateral zone for one of the embryonic poles’ tissue, and another zone (a rib orientated zone) for the other.

I’d venture the lateral zone would have the highest rate of cell division; thus the site of anus formation. And the “rib” zone would be like a flat layer of cells the form the body tissue.

The anus founder cells would occur when peri-clinal cell divisions occur in deep layers of stem cells. This creates lateral zone thickening and the pole’s stem cell niche area will be greatest when anus tissue forms; followed by a phase when that zone’s stem cell niche area is at it’s smallest once anus tissue has been initiated.

Different hormones will influence the di-polar stem cell niches’ size and level of activity; sometimes in opposite ways. And the different hormones will also have functions in supporting the individual stem cells in a niche.

Toti-potent regeneration (ability to regenerate everything) rests on the organism having tissue cells that are able to re-enter an appropriate cell cycle. Cells out of cycle for differentiation into new tissue are in the “GO” phase.

Apparently this organism has cells that can re-enter the “G1” cell cycle (DNA replication preparation of the cell for “G2” when mitosis set-up preparation occurs; only then does DNA replication occur in “S” cell cycle phase). Not all cells can re-enter “G1” and I assume the organism has some functional tissue that is little specialized; this is what would retain the cell division capacity to re-enter cell cycle “G1”.

Reply to  gringojay
May 7, 2021 9:23 am

edit: sorry about last paragraph, but cell cycle progression is G1 to S to G2

Reply to  gringojay
May 7, 2021 12:11 pm

The cutting into parts “wounds” the tissue and internal hormones go to the site. I surmise one of the hormones causes a drop in pH and molecules/compounds are set free from nearby tissue.

Then carbon and hydrogen form up as CH2-CH2 (ethylene), which modulates the cross-talk among hormones. This leads to relevant genes being active in the euchro-matic region of chromatin in tissue cells competent to re-enter the “G1” cell cycle (verses tissue cells that are recalcitrant and can not move to “G1”; these stay in their hetero-chromatin state).

Methyl-ation and de-methyl-ation of DNA influence regenerative genes. There’ll likely be one hormone that blocks methyl-ation changes and another hormone that will boost methyl-ation. The synchronized inter-play of these hormone action at appropriate times would be a function of changing levels of CH2-CH2 ethylene.

What remodels eucro-matin into hetero-chromatin is gene silencing; which involves methyl-ation (of lysine 9 in H3 histone tail of a nucleo-some). However, the unphysiologic high amount of the hormone coming to the cut (the same hormone that drops local pH to free up carbon to make CH2-CH2, and corresponding hydro-lytic enzymes to free up hydrogen) and that hormone also acts to methyl-ate H3 histone and DNA gene(s).

Gene availability for transcription depends on methyl-ation (of cystein residue) since methyl-ation causes non-transcript-ion of DNA. But the in this same focused high hormonal post-wounding cut scenario gene silencing of some genes (by the “shock” impulse of that hormone) actually allows other key regenerative genes that are normally only minimally held as hetero-chromatin to become potential players (ie: revert to having transcribed DNA, which is present in euchro-matin.)

The fate of stem cells is specified by position and progeny of stem cells that remain in the ideal position (likely summit of a stem cell niche) remain pluri-potent. Daughter cells that leave that position are what differentiate. Then it is asymmetrical division of those daughter cells that cause different cyto-plasmic determinants; which causes daughter cells to exhibit different fates. Asymmetric cell division occurs in response to incoming hormones’ varied cross-talk altering the cell polarity; this occurs by interference with either/or the electrical field around that daughter cell, and/or pH.

Why only 3 pieces are regenerated? The size of those tissue pieces dictates the amount of internal hormones that are found in any single piece; too small a piece beyond 3 presumably will have inadequate diffusible substances.

John Tillman
Reply to  gringojay
May 7, 2021 3:20 pm


Wonder if they tried four or more pieces.

John Tillman
Reply to  gringojay
May 7, 2021 3:49 pm

Not surprisingly, most bilaterian groups are mouth-first protostomes, eg belonging to the arthropod, mollusc and tardigrade phyla.

Malcolm Chapman
May 7, 2021 5:30 am

Always grateful to WUWT, not least when it comes up with beauties like this, and comments from people that have heard of ascidia.

John Tillman
Reply to  Malcolm Chapman
May 7, 2021 7:39 am

One sea squirt species is eaten in Korea and Japan:

May 7, 2021 6:44 am

Teach steers and swine to do that, and we’d all need only one of each. Saving the planet and all the steak and bacon we’d ever want! (yes, sarc)

May 7, 2021 7:34 am

Based on the title, I thought it was going to be about the communist organization worldwide.

Gary Pearse
May 7, 2021 8:06 am

A number of decades ago I read of experiments at DVA of attempts to regenerate lost limbs using low level electric current. They apparently re-grew a bat’s wing and actually reported minor regrowth of tissues including bone in an amputated human leg. I never heard any more about it so maybe whatever apparent tissue growth there was turned out to be natural.

Reply to  Gary Pearse
May 7, 2021 3:22 pm

maybe they figured it out and don’t want to tell you.

But would the newbie would still be just as old and drooly as the original (like when they regrew Biden during the election).

Do the telomeres in the regenerated ascadians look the same as the original, or are they good as new?

John Tillman
Reply to  DonM
May 7, 2021 3:36 pm

The original parts of the sea squirts’ chromosomes would be the same.

Reply to  John Tillman
May 8, 2021 8:17 am

‘the originals would be the same …’

Are the regenerated parts of the animal the same ‘cellular age’ as the original base part … likely yes, right?

Do you know if they have checked?

Krishna Gans
May 7, 2021 8:41 am

EurekAlert! without the word climate change, global warming or human fault !!!

John Dueker
May 7, 2021 10:23 am

Cloning through vivisection? You first I’ll watch.

michael hart
May 7, 2021 3:41 pm

I recall my PhD supervisor once telling his research group that developmental biology remained one of the least well understood areas of science, yet also one of the most dogmatic. He was cautioning us about what we might ever say/publish in immunology, using developmental biology as the leading example, as he saw it.

He was probably right about the first point (the science) and increasingly right about the second (the dogmatism).

Since then, looking at climate science and its bastard offspring, I have started to realise just how much freedom of thought we were gifted only a few decades ago.

John Tillman
Reply to  michael hart
May 7, 2021 3:50 pm

The loss of which is sad and worrisome.

May 7, 2021 6:27 pm

Inline with these topics I have found the recent work by Dr Michael Levin to be fascinating. The possible role of bioelectrical coding in the outcome of cell growth and development is something we seem to know little about.

Reply to  diggs
May 10, 2021 10:09 am

So, we cant just cut off the ‘cats’ tail’ and expect that the kittens are born without tails.

We have to cut off the tail at the right time and in the right way …:)

May 8, 2021 2:15 pm


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