The Dragon Ball series features many amazing techniques, but among all the moves that have appeared over the years, Fusion is surely one of the most popular ones. For one, Fusion is always exciting to watch, as two different characters combine to form a new fighter with their own unique looks, personality, and a vastly boosted Power Level.
In addition, the movements and poses used in the Fusion Dance are iconic in their own right, although some characters like Trunks have voiced their concerns about the coolness factor of the technique...

In the original series, Goten and Trunks master the Fusion technique and use it to combine into Gotenks, an amazingly powerful fighter who was even able to go head-to-head with the terrifying Majin Buu. Fusion between two humans in the real world is a bit hard to fathom, but in regard to those two half-Saiyans, just what could be happening when they fuse together?

To find out, we spoke with Professor Naoki Wada, who is researching cell engineering at Tokushima University's Graduate School of Technology, Industrial, and Social Sciences. Professor Wada was the first person in the world to successfully achieve partial cell fusion between a human cell and a plant cell. When we asked about the mechanisms that could be behind Dragon Ball’s Fusion, they shared some insights that completely blew us away!

Profiles

Interviewee: Naoki Wada

Assistant Professor at the Laboratory of Molecular Plant Breeding in the Division of Bioscience and Bioindustry at Tokushima University's Graduate School of Technology, Industrial, and Social Sciences. As a Japan Society for the Promotion of Science Postdoctoral Research Fellow, succeeded in the world’s first cell fusion of human and plant cells with Professor Kiichi Fukui from Osaka University's Graduate School and others under the guidance of Professor Mitsuo Oshimura from Tottori University. The Fusion he’d like to see most is one between Gohan and Piccolo.

Interviewer: Yuuka Higaki

​Editor and writer. For as long as she can remember she has always been more of a humanities student, with her weakest subject being science. Since becoming an adult, she is starting to appreciate the fun of science through various forms of entertainment like manga.

Contents

・"In Fusion, Zygotes Stick Together" Theory
・ What Happens When You Wear Potara Earrings?
・ Does the Secret of a Fusion's Duration Lie in Meiosis?
・ The Forefront of Fusion Research

―For starters, just what phenomenon does the term "fusion" refer to?

Prof. Wada (Hereinafter, Wada): There are many ways to look at fusion, but in terms of cell fusion, it’s when two cells come together and become one cell. Cell fusion happens in nature, with one easy example being reproduction. During reproduction, a sperm fertilizes an egg. That’s fusion.

In addition, certain kinds of cells in muscles and bones fuse together to form large cells in the human body. If we speak in terms of microorganisms, yeast is a good example of fusion. Yeast itself is a single-celled organism, but it reproduces by having two differing types of cells fuse together.

―Wow, it sounds like fusions are happening all around us! Professor Wada, what attracted you to this field originally?​

Wada: Personally, I’m more interested in artificial fusion as opposed to fusion that occurs in nature. I wonder whether it’s possible to get close to some of the fundamental structures of life by artificially causing phenomena that do not occur in nature.

In terms of the world of Dragon Ball, I’m interested in the ecology of Planet Namek. Namekians are also masters of fusion, after all.

―In Dragon Ball, Fusion is a skill where two warriors fuse and become one super powerful fighter. Considering what is known about cell engineering, what do you think is happening when these characters fuse?

Wada: Well first off, fusion in the natural world occurs when both parts of the fusion are single-celled. I don’t think there’s ever been a case where two multicellular organisms have fused in the way that Trunks and Goten do.

There’s something called "grafting" that some people may have heard of before. Grafting is a technique that joins two plants together into one. But rather than just mixing the entirety of two plants together, they are joined so that the top portion comes from the 1st plant and the bottom portion comes from the 2nd plant.

When I thought about how two distinct individuals like Goten and Trunks could combine into one as they do when they fuse into Gotenks, I came up with two hypotheses as to how this could happen.

―Really?! What are they?

Wada: My first hypothesis was that the cells within the two individuals mix completely without actually fusing. But, in that case, I think the fused individual would have mosaic-like results for color and such. For example, in terms of eye color, the new individual should have a mix of Goten’s black eyes and Trunks’ blue eyes. But Gotenks’ eyes are completely black, so that hypothesis wouldn’t work.

Wada: Since that’s the case, the only other option is cell fusion. But it’s difficult to imagine that two individuals could fuse entirely, so I came up with the "zygotes sticking together theory".

―Wow! Could you tell us a bit more about that theory?

Wada: Dragon Ball’s Fusion involves a process where each person touches the other’s fingers after doing a unique movement, and then there’s a burst of light. In that instant, the two trying to fuse each returned to their single-celled zygote (or fertilized egg) state, and then the two zygotes fuse to become one fused cell, which then grows rapidly, becoming a single individual.

This seems ridiculous for humans, but it seems possible that a single individual with the genetic information of two people could exist. The three processes "return to the zygote", "fusion", and "growing into a human form" all occur instantly.

―One of the conditions for a successful Fusion is that both fighters' Ki have to be exactly the same, so that may have a influence the process as well. By the way, when two people combine into one via Fusion, the fused person is immensely more powerful than either of the parts. Is that true for fusion in the real world, too?

Wada: In the plant world there is something called heterosis. When two parent plants are crossed to create a hybrid, the result is a seed that is better than the original parents. By combining two plants with entirely different characteristics, the advantage is that the new plant can sometimes obtain properties from one that the other didn’t have originally.

However, as a general rule, species that are more closely related are likely to interbreed more successfully. It’s easier to preserve things with similar DNA.

―So since Goten and Trunks are both half Saiyan, they were a good match in that sense.

―In Dragon Ball, there’s another method for characters to fuse. In this method, it doesn’t matter how different the individuals are; just by each of them putting on one of the Potara Earrings, they instantly fuse. How do you think this differs from Fusion?

Wada: If we assume that Fusion is a skill that allows things with similar characteristics to fuse, I think the Potara Earrings are an item that forcibly fuses things that cannot perform a Fusion.

―That seems similar to the artificial fusions that you’re researching, Professor Wada.

Wada: That’s true. For example, for the cellular fusion of a human cell and plant cell I performed, I used a reagent called polyethylene glycol to weaken the cell membranes of each of the cells.

This allowed them to stick together. This "forcing them together" aspect may be a characteristic that is shared between my research and a Potara Earring-based Fusion.

―Potara Earrings were originally a special treasure of the Supreme Kais, so it is quite a rare item indeed.

―Another difference between normal Fusion and Potara Earring-based Fusion is that Fusion only lasts 30 minutes, while Fusion via Potara Earrings (when used by people other than a Supreme Kai) only lasts an hour. Is there a Fusion with a duration like that in the natural world, too?

Wada: Fusion in the natural world is basically irreversible. Just as a zygote will never go back to a sperm and an egg, cells that have fused together can’t just go back to their original states.

However, there is a phenomenon where genetic information of a cell is distributed to new cells. The process of creating sperm and eggs is called meiosis.

Human cells have two sets of genetic information, one set from the father and one set from the mother. And, through a process called somatic cell division, new cells that have two sets of genetic information are created.

But reproduction cells like sperm and eggs are a little special and only contain one set of genetic information. This cell division is called meiosis.

Furthermore, normal Fusion and Fusion via Potara Earrings, where a fused individual can go back to the original two, might involve meiosis.

―Meiosis, somatic cell divisions... I remember learning about this in school.

Wada: If Goten and Trunks fuse via the method I hypothesized earlier, Gotenks should have retained the genetic information of both Goten and Trunks (2 sets + 2 sets = 4 sets). Otherwise, there would be no way for Gotenks to split back into Goten and Trunks.

Then, when the time comes (30 minutes for Fusion), something forces the cells to go back to one cell, and the meiosis occurs. Perhaps the time limit of the different methods of Fusion is related to this.

―So in the case of Gotenks, in order for Goten and Trunks to split back into their original selves after the Fusion ends, they must go back to being single-celled.

Wada: When Gotenks returns to being single-celled, meiosis occurs. Cells with the original genetic information from only Goten and Trunks are created (during meiosis in the natural world, cells are recombined within DNA, and the original sequence may change). Afterwards, each cell multiplies and grows, and they eventually go back to Goten and Trunks.

Wada: ...Actually, it’s quite acrobatic, but I think this is how it would happen if it were possible in the real world.

―Thank you for such an fascinating explanation! There are many mysteries of life that might be behind Fusion!

—Finally, I'd like to ask you about fusion in the real world. Just what research is being conducted at the moment?
​
Wada: Well, as far as research that I am involved in goes, there are studies being conducted to find out if the chloroplasts plants need for photosynthesis can be also used within animal cells. If successful, this research could lead to the creation of animal cells that can perform photosynthesis. It could even lead to lifeforms like the Namekians in the far-off future. (Laughs)

*In the 2022 article "The "Namekians Are Plants" Theory - Dragon Ball Fan Turned Biologist Explains the Mystical Link Between DB Characters and Evolution!", Yudai Okuyama, a researcher at the National Museum of Nature and Science, hypothesized that Namekians might generate the energy they need to survive via photosynthesis.

In addition, progress is also being made in research relating to matter production. For example, if cells that create antibodies in response to pathogenic bacteria could fuse with cancer cells, the new cell could use that proliferation function to multiply while creating antibodies. There have even been attempts to artificially keep creating antibodies using this approach.

—Professor Wada, if you weren't bound by technological constraints, what would you like to try fusing together?

Wada: I'd like to try fusing two organisms that were vastly separated on the evolutionary spectrum to see what would happen when they were combined. I'd then like to perform a variety of experiments so I could come closer to the answer of how life is established.
​
Take human beings and plants, for example. They are separated by 1.5 billion years of evolution, and yet their cellular structure is similar. They both share DNA, chromosomes, and many other aspects. The fact that these aspects have been preserved despite their very different evolutionary tracks hides some vital information about the factors that enable life as we know it.

—When you put it that way, humans and plants start to seem like relatives that aren't really so distant at all. Thanks so much for agreeing to take part in this intriguing discussion today!