A chimera is a mythical beast that is a combination of several different animals – lions, birds, dragons, snakes. They differ based on the area they’re from. Chimerism is also present in humans, though it’s a little different. It happens when a person has two sets of genomes, from when a twin is partially absorbed by the other twin in the womb.
It manifests in a variety of different ways, such as heterochromia, but true chimerism is quite rare, with only a hundred people in the world exhibiting it. Researchers believe there may be many more, but it can be difficult to determine.
The Stinkiest Mutation
We can all get a stink about ourselves when we're working hard or spending time in the heat. A small number of people, however, are doomed to emit a constant, unpleasant smell. There's an enzyme in the body responsible for breaking down the chemical trimethylaminuria, which comes from digesting eggs, beans, and fish – some really stinky foods.
A mutated FMO3 gene prevents the enzyme from being produced which results in someone suffering from a strong, noticeable body odor that people have called similar to rotting fish. It's a rare occurrence, happening in less than one percent of the population. Thankfully.
Super Strong Children
For most of us, getting big and strong requires working out the right way, eating the right food, and a bunch of other things. Sleep is a big one. For people who have inactive myostatin genes, however, it requires nothing at all. Well documented in mice and cattle, children who have this mutation are born swole, possessing bigger muscles and greater strength.
There hasn't been a great deal of research done on the condition, but so far there are no long-term health issues associated with it. People with this condition also tend to have reduced body fat, though increased muscular strength isn't always part of the deal.
The Worst Bad Hair Days Ever
We've all struggled with hair that doesn't want to play nice, but have any of us ever had “uncombable hair syndrome?” It's the result of genetic mutations affecting the proteins that form the hair shafts on the head. Nowhere else on the body, thankfully. The development of the hair makes it impossible to be combed flat.
Those who are blond or straw-haired are more likely to have this than other shades, and it tends to stick out from the scalp in random directions. Luckily, there are no other health problems it and does tend to calm down with age.
No Surprise Parties for These People
Have you ever heard “Jumping Frenchmen of Maine?” It's a rare disorder for someone who has an uncontrollable reaction to being startled. A person with this condition might scream, flail their arms, jump or start a fight. Even stranger effects are repeating words, mimicking movements, or mechanically following simple commands. The symptoms begin at puberty, but slowly reduce as age progresses.
The name comes from French Canadian lumberjacks working in Maine, but the behavior has been seen in Louisiana, Malaysia, Siberia, India, and elsewhere. Researchers are unsure if it's genetic, environmental, cultural, or what. Be careful around such people, or little jokes will become much worse.