The Chimera is a fictional beast from Greek mythology that first appeared in Homer’s Iliad. The fearsome beast was the offspring of Typhon, a giant considered to be one of the deadliest monsters in Greek Mythology and Echidna, who is considered to be the mother of all monsters in Greek mythology. In the original description the Chimera had three heads (lion, goat, and dragon), the front quarters of a lion, the hind quarters of a goat, and a dragon for a tail. Additionally, the goat head was able to spit fire. Bellerophon was able to slay the beast while riding the winged horse Pegasus, for King Iobates.
The legend of the Chimera remains strong as it still appears in popular culture and media to this day. The myth has even made it all the way to Japan, where it has appeared in a variety of anime including Mon Colle Knights, Yu-Gi-Oh, Duel Masters, Hunter x Hunter, and perhaps the most famous adaptation, Full Metal Alchemist. While some still use the Chimera in its original three-part form of lion, goat, snake/dragon, others have used slightly different forms for their version of the Chimera. While these new takes on the beast may not include a lion, goat, or snake/dragon, they all are a fusion of multiple animals to create a new and truly unique beast. In the case of Full Metal Alchemist humans are used to make Chimeras in order to make a superior soldier.
Clearly the mythological Chimera does not exist as there aren’t any reports of fire-breathing three headed monsters terrorizing the Greek countryside. However, what about the more modern interpretation of the Chimera, where there is a fusion of different types of animals? Unless you are talking about the Chimera fish (Ghost shark), a cartilaginous fish that lives on the ocean floor,, the answer would be no.
That being said, science has decided to tweak the definition of the Chimera one more time and that is where the fun really begins. Scientifically a chimera is an individual composed of two or more genetically different cell types. In layman’s terms think of it like combining half of a Nissan Altima and half of a Nissan Maxima to make a car. Since the Altima and Maxima are both Nissan sedans, there is a good chance of the car actually functioning. I know what you are thinking: what possessed scientists to even attempt to fuse two different animals together outside of being fans of the Island of Doctor Moreau?
Actually, nature did it first and perhaps the most striking example is something called Gynandromorphism, where one half of the animal is male (XY) and the other half is female (XX); thus, the body is composed of two genetically different types of cells.
Nature can do one better though, and that is something called Tetragametic chimerism. In this case an animal is set to have fraternal twins (siblings being born at the same time), and instead of the newly fertilized zygotes staying separate and developing normally, the twins fuse together, leading to the birth of one offspring instead of two. As it turns out, a great many marmosets turn out to be this particular type of chimera. It can also happen in humans but it typically goes unnoticed.
The mythological Chimera is of course busted, but there are still creatures that have the genetics of two closely related but distinctly different individuals, so some form of chimera is possible. This of course leaves the door open for science to perhaps create something closer to the original Chimera or perhaps something like what we see in Full Metal Alchemist.
Beatrice Mintz created the first man made chimeras in the 1960’s. How she did it was by fusing two separate mouse blastocysts (an early stage of embryonic development) and then insert the fused embryo into a third female mouse, where it grew to term.
As you can see, the resulting mouse exhibits traits from both of the parent mice. Dr. Mintz went on to make over 25,000 mice using the above technique. Now I know what you are thinking “this is all well and good, but when are we going to start fusing different animals together.”
It only took scientists about twenty years to take the next step, combining the cells of two different animals using a process based on Dr. Mintz’s work. In this case it was a sheep-goat chimera also known as a geep.
The geep is a fully functional organism that can reproduce in some cases. However, it either has sheep, or goat offspring based on which parent’s cells formed the reproductive system. This helps to illustrate my next point and that is while the geep is a cross species chimera, it works because the sheep and goat are both in the same sub family Caprinae. It also highlights that it is two separate groups of cells working together, but still separate, and not a true fusion as seen in fiction. That being said, it is not a useless science project, and there is some interesting research still going on that could have a great impact on medicine.
A variety of diseases and conditions can cause one or more organs to fail, which up until 63 years ago meant a death sentence for the patient. The first successful kidney transplant took place in 1954, with other successful transplants taking place in the succeeding years. One of the major problems with organ donation is that the demand for organs far outpaces the supply of donor organs. There are several different approaches that can be taken to help alleviate the problem, such as organ donor cards. However, a recent study might offer great relief for people waiting for organ transplants. The idea is that if we can create a geep, why can’t we do the same thing but fuse a human embryo and an animal embryo. The plan is not to create a man-bear-pig, but have the animal with the internal organs of a human. Specifically, the animal being used is a pig, which actually has a number of similarities with humans internally, and can be easily grown. The study of course raises a number of ethical issues that are beyond the scope of this article.
Can the mythical Chimera exist? The answer to that is a definitive no. However, as to other fusions of animals existing, the short answer is yes. However, the answer is a bit nuanced. It is possible to fuse different members of the same species together embryonically, and this does occur in nature from time to time. It is of course possible to fuse different species together embryonically as seen with the geep, and the human pig fusion. That being said, however, scientists cannot just fuse any two organisms together, because if the animals are not closely related, the fusion will not work, or not work as intended. This means that cross species chimeras that are closely related are confirmed.
Full Metal Alchemist
When it comes to the chimeras in Full Metal Alchemist, they are completely busted, because real world chimeras form in the womb, and cannot be made later in life by fusing two organisms together. Next, the anime combines humans with species that are not closely related to us, such as snakes, crocodiles, etc. The only two chimera that would work on this basis would be Darius (human/ gorilla hybrid), and Zampano (human/ pig). Additionally, the chimera would not be a complete fusion of two organisms, so the resulting chimera would not have increased abilities as a result of this fusion. For example, Dolcetto is a fusion of a human and a dog. This granted him an enhanced sense of smell similar to that of a dog.
When speculating I have to look at what science has already accomplished and in the case of the geep, it is half sheep, half goat. Now if Dolcetto was created at birth as a dog-human fusion, his brain and general skull shape would have to be that of a human so that he can have a human personality and intellect.
Well duh, but what if he had a dog’s nose?
1- The sensory receptors for scent are not actually any better than that of a human, their increased sense of smell comes from the fact that they have a much larger nose or surface area than a human.
2- If by some chance, you could have a larger amount of nasal epithelium, there is more than a good chance that a human brain would not be able to process all of the signals it receives. Think of it like having the biological version of the blue screen of death.
Lastly it should come as no surprise that the chimeras would not be able to shift between a human and a more bestial form. Now you all know what is coming by this point, and, yes, the Full Metal Alchemist chimeras are busted.
“But teacher you didn’t talk about making chimeras by inserting animal DNA into the Human Genome?”
True, I have not talked about gene editing and other genetic technologies which will be the subject of a separate post given that this one is over 1500 words. So you have not seen the last of chimeras.