Remember your seventh grade Home Economics teacher who screamed, “You’re burning your oleo!” as you tried to make rice crispy cookies? Or what about that guy at the bus stop who looks creepily in your direction every day and never seems to blink? Oh, and let’s not forget that kid in the Walmart cereal aisle who was pitching a fit because his mom wouldn’t buy Sugar-Frosted Caffeine-Crusted Attitude Agitator cereal for breakfast.

Admit it… At times, you have suspected some of the people in your life are aliens. Well, if not exactly extraterrestrial, then at least not entirely human. As it turns out, your suspicions are entirely correct. Each of those suspicious individuals is, at best, only 92-95% human.

Scientists have confirmed that 5-8% of a person’s DNA isn’t human. They believe everyone carries about 100,000 pieces of DNA from retroviruses that have built up over thousands of years of human history.

Geneticists have succeeded in mapping the lion’s share of the human genome. It consists of about 22,000 genes, each of which plays a part in making every person unique. In the course of identifying the human genetic composition, scientists discovered that as much as eight percent of our DNA is genetic baggage — remnants of ancient viruses. Another 40 percent consists of repetitive strings of genetic letters believed to have originated from viruses. You can thank these alien invaders for gifting us with life’s little delights, such as hemophilia, multiple sclerosis, certain types of dementia, and cancer.

The nature and function of the viral part of DNA eluded biologists for years, prompting them to refer to it as “dark matter” within the genome. Clearly, it does not participate in the normal functions or construction of the body, but it appeared to be doing something. What that something was, however, stumped the best of minds.

Geneticist Barbara McClintock discovered in the 1940s that some parts of DNA behave like infectious invaders. These DNA chunks can move around through the genome, copying and pasting themselves wherever they see fit. McClintock referred to these peculiar pieces of the puzzle as “jumping genes.” Although controversial at the time, researchers have since confirmed her suspicions, earning her a Nobel Prize in 1983.

The “jumping genes” originate in the viral portion of the genome. Many of them are helpful, but some turn the human body into a ticking time bomb. All it takes is one little trigger from an external source, and the disease-causing “jumping genes” go into overdrive. Finding the triggers for these bad actors is what drives the work of many genetic pathologists.

Identifying the distinct triggers is much like trying to locate a needle in a haystack. Aside from the fact that the human genome is massive — it consists of 3 billion base pairs of DNA — the task is complicated because about 99.9% of all DNA in humans is identical. It is just 0.1% that gives you different hair, eye, and skin color than anyone else on the planet. As if that weren’t enough, 96% of our DNA is shared with primates such as gorillas, chimpanzees, and orangutans. For that matter, we share 70% of our DNA with slugs and 50% with bananas.

That means, in summary, that the person closest to you right now isn’t entirely human and is a monkey’s uncle. He or she has a genetic predisposition toward sluggishness and is at least halfway bananas.

By the way… the same is true about the person staring at you from the mirror.