Does Shin Uchia really understand biology?

Does Shin Uchia really understand biology?

Shin Uchia

Shin Uchia is a short-lived antagonist in the ongoing “Boruto: Naruto Next Generations Continuation” of the long-lived Naruto franchise. Not much is given about his background beyond his being a former test subject of Orochimaru. What makes him so special is that he has a rare gift: his genetics are such that he has no risk of rejecting an organ or tissue donation. It is due to this unique trait that he develops some interesting thoughts on humanity and evolution.

Immune System

The first step in examining Shin Uchia’s unique ability to receive any donor tissue is to discuss the immune system. The immune system is the system that protects the body from harmful infections (bacterial, fungal, viral, and/or parasites). There are many facets to the immune system, far too many to discuss here, but for simplicity I will say that it can be divided into two parts, innate immunity and acquired immunity. It is the acquired immunity that is of concern to us at this time.

Acquired immunity is also called the adaptive immune response. It is this system that creates specialized responses to individual infections, be they bacterial, viral, fungal, or parasitic. This is why vaccines work, because once the body is exposed to an invading agent, it creates a response to that specific agent. The body then remembers that response for the next time the body is exposed to the same agent. This means that on the second exposure you don’t get sick, or at the very least not as sick as you could have been. It is also this system that is the bulk of the reason that a person’s body rejects a donated tissue or organ.

Organ Transplant

The first successful organ transplant occurred on December 23, 1954, when a kidney was transplanted between a set of identical twins. FYI- The kidney is one of the organs that a person can donate without having to be dead, because the human body has two kidneys, and only needs one to function normally. Organ transplants are tricky procedures because not only do you have to remove a defective organ and replace it with a functional one without killing the patients, but you also have to make sure that the recipient’s (the person receiving the organ) immune system does not attack the donated organ ultimately destroying it, because it does not look like the recipient’s body to his/her immune system.

While modern medicine has not completely overcome the organ rejection problem, it has made great strides in reducing organ rejection. The amount of time people will survive after organ transplantation varies depending on the organ, and the kidney is the most commonly transplanted organ, and 50% of patients can expect to live 10 years. This is accomplished through antirejection drugs, and proper matching. Antirejection medications are drugs that suppress or partially shut down part of the immune system (for the computer inclined it is like underclocking your CPU).

It is the matching that I am most interested in when discussing Shin Uchia, because of his unique trait of not rejecting organ transplants. Matching is the process by which doctors try to find an organ that shares similar genetic markers and proteins as the patient. Essentially doctors are looking for an organ that will look as close as possible to your own, reducing the chance that your immune system will see it as an invader and destroy it. The first marker doctors will look for is the blood type. The easiest way to explain this is by briefly discussing blood transfusions. There are four human blood types (A, B, AB, O) and depending on the type of blood, an individual will have a unique set of markers on his or her blood cells, and antibodies to attack the opposite type. This is why when you give someone with A type blood, B type blood, it (the B type blood) agglutinates or clots, destroying the blood cells. Now imagine this happening with an organ and you can see why it is important to get the matching correct. FYI– the diagram below will explain which blood types can be donated to each other successfully and I left out the rhesus factor for simplicity.

Shin Uchia

The second marker set to be matched is the major histocompatibility proteins, with the information for them found in Human Leukocyte Antigen complex (HLA), which is a series of genes found on chromosome number 6. These proteins are necessary for the proper regulation and function of the immune system, specifically the adaptive immune system. If the donor and recipient HLA’s match (or are very similar), then it is harder for the recipient’s immune system to recognize the donor’s organ as not being part of his own body. This greatly reduces the chance of the organ being rejected. This is why family members are often the first place to look for organ and tissue donation, as they will share more HLA genes, increasing the likelihood of a good match.

Shin Uchia’s ability

Now that our brief dalliance through the immune system and organ transplant is over, we can now discuss Shin Uchia’s unique ability of being able to take organ and tissue donation from anyone he wants without fear of rejection. Sadly, in the real world this is impossible. Now if you looked carefully at the blood typing diagram, you would have noticed that blood type AB can receive all of the other blood types. Yes, if Shin Uchia was blood type AB he would be a better match for some tissues and organs, but there is still the HLA matching.

If he lacked the entire HLA complex, his acquired immune system would be severely compromised, and while this might reduce his risk of rejecting the donor organ, it would not remove the risk entirely. The donated organ would have the major histocompatibility proteins, and the parts of Shinn’s immune system that still worked could eventually attack the donated organ. There is also the matter of his lack of acquired immunity, which would put Shin at risk for a number of diseases including, Streptococcus pneumoniae, Hemophilus influenzae, Pneumocystis jirovecii, Giardia intestinalis, Cryptosporidium parvum, Herpes simplex virus, Mycobacterium, Listeria, and intracellular fungal infections, just to name a few. Needless to say, there is no way Shin Uchia is going to be running around the world trying to enact his plans.

Shin’s transplant operation

The actual transplant operation that we see Shin Uchia perform in Boruto episode 22 is slightly more realistic. Shin Uchia takes a liver from one of his sons, who are actually clones made from pulp of his own teeth. The pulp is the innermost part of the teeth and contains living tissue, and clones could be made from this tissue.


Shin’s receiving an organ from one of his own clones would be the same as an identical twin receiving an organ from their own twin. Organ donation between identical twins is exceedingly rare, but all of the information I could discover has shown that rejection is not an issue. In the cases where the donation failed, it was due to the condition that caused the need for donation in the first place. In this regard Shin shouldn’t have any worry of rejection when taking an organ from his own clones.

Shin Uchia

Sparkly magical ninja BS aside, holy lack of sterile technique Batman! Shin Uchia takes no care to clean the surgical sites or keep the liver he removed from his clone clean during the surgery and he is just asking for a massive post-operative infection. My second issue with this scene is that it is clearly a liver that was transplanted and there was no need for him to kill his clone to get it. The liver is the only human organ that can regenerate itself, so it is one of the few organs that can be donated by live donors. A small segment of the liver is removed from the donor patient and placed in the recipient. If there is no rejection, then the liver will grow back to its full size in the recipient. The donor’s organ grows back as well. Since Shin Uchia has enough knowledge to perform transplant surgery, he had to know about the liver’s ability to regrow, proving just how much of a jerk he really is.


As shown above, there is no way for Shin Uchia to have any combination of traits that reduces his risk of non-clone organ transplant rejection to zero as stated in Boruto, so I have to call this one busted.

Shin’s Ideology

By his own admission, Shin Uchia is rather taken with the idea of survival of the fittest and I was rather surprised to find an anime reference the more modern take on Darwin’s theories which incorporates what science has discovered about DNA and genetics. So, while Shin Uchia isn’t technically wrong in his musing, he does leave a bit out. When it comes to evolution, it’s not about strong or weak, but fitness. In layman’s terms fitness is the organism’s ability to survive in the environment and reproduce. This means it is possible to have an organism that we might consider to be very weak, but if it is able to reproduce, then it is successful on an evolutionary basis. He also mentions how genes can hybridize, and what I think he really means is that an organism receives different sets of alleles for a particular gene from each parent and the more varied its alleles are, the more fit the organism usually is. This is why mutts are often healthier than purebred dogs, since their genes are more varied.

Dog evolution

Where Shin Uchia goes completely off the rails is when he talks about starting more war and conflict as a way to spur on evolution. He speaks about how war and conflict select for stronger and stronger ninja, as only the strongest would survive, focusing heavily on nature and completely forgetting the nurture part of the equation. The example I like to use is that you can have two Olympic class athletes have a child, but if he sits on the couch eating cookies all day everyday he will never reach the level of his parents. This is sometimes seen in the famous Kenyan distance runners, who used running as a means to get out of poverty and find a better life. Their children, who share their genes, grow up in a different environment and do not always reach the same level as their parents.

Warning: Non-science content

This can be written off as part of Shin’s character, and I also think it shows a bit of Masashi Kishimoto’s lack of science knowledge and/or his own mentality. This is so because many of the extremely powerful characters are related to other powerful characters or families. In fact, the only main character who is not in some way related to a powerful family or person who gains power is Sakura. In this way Naruto is subtly sending the message that your birth matters more than what you do with your life. Ok, soapbox moment over.

Back to the science

Shin’s idea of using a war to drive evolution is laughable, as evolution is always happening and sometimes faster than we think.

All Shin’s plan of starting another war will do is select for traits that benefit fighting. In essence, Shin is trying to start a massive selective breeding program. Given what we know about purebred dogs, and other purebred animals, where they show a higher rate of a number of debilitating conditions, it is not going to end well. By only selecting for genes/traits that benefit fighting it is entirely possible that genes/traits that are needed for reproduction could be lost along the way, making it harder for humanity to sustain itself. Not to mention that civilians would not be involved in the fighting and not subject to the war, again selecting for certain genes/traits.

Basically, Shin Uchia wants to institute a eugenics program for the humans of the Naruto universe, and while it was attempted in the real world, it did not end well. Legal, ethical, moral, and scientific reasons aside, it never worked in the past, and at the current time the idea of eugenics is basically dead in the water for good reason. The closest thing to eugenics that exists in the world today is the use of prenatal testing, which is used in some circles to make sure the fetus is perfectly healthy, and fetuses with severe disabilities are aborted. This doesn’t really lead to a change in human genetics, due to not its being used across the entire population, and also due to genetic principles that are beyond the scope of this course. These tests can also be used to determine the biological sex of the child, and again in some circles this is used to determine if the fetus should be aborted or not. While this has skewed the male/female ratio in certain countries, it has not affected humanity as a whole.


Shin Uchia’s ideology is warped, but he does a pretty good job on some of the science, but in the end his goal of forcing human evolution is still impossible because not every single person will be involved in his war.

Thanks for reading and please leave any questions or comments below.

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