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Accidental discoveries are a common theme in science. The most famous is probably the discovery of penicillin, the world’s first antibiotic.

It happened when Alexander Fleming noticed that the bacteria he was growing in Petri dishes didn’t seem to grow near mold. Usually, we like to think of these findings as fluke events. The reality, though, is that each discovery, even if triggered by a silly mistake or poor lab practice, is actually the result of careful observation.

Someone had to make surprising connections to explain what they were seeing. They didn’t necessarily find the answer to whatever they were looking for, but they did find something, and in many cases something much bigger. So, here are 6 of our favorite times that scientists, totally by accident, but also because they were clever enough to piece it all together, discovered some awesome things.

First up, an entirely new way to think about infection and sex drive. Yeah, we’re just jumping right in. About five years ago, Canadian biologist Shelley Adamo was working on understanding whether crickets’ immune systems go haywire if the insects are stressed out by things like predators.

A student generously brought in their pet bearded dragon to serve as a very realistic fear stimulus. But unbeknownst to everyone, the lizard was carrying a deadly virus, at least deadly for crickets. So the insects were scared, but the real scare was to come.

Because a few weeks later, the crickets’ insides had turned blue, and all of them were dead. Now, the normal reaction to this might be to just order some more insects, or find a slightly less dangerous predator, and re-do the experiment. But not Shelley Adamo.

She noticed that, before the crickets met their untimely demise, they were more interested in sex than normal. Which is just weird, because the typical response to an infection is to be sick, and not waste energy trying to procreate. Adamo was intrigued, and went on to document how the virus seemed to be working.

She saw that the virus increased its spread by making the insects more interested in mating. That way, when the infected cricket’s antennae touched its partner’s mouth, something that basically only happens during sex, the virus could get passed along. In short, it’s a cricket STD.

Or, as Adamo puts it, a parasitic aphrodisiac, which could be a great band name. All this thanks to a bearded dragon that happened to be infected with a special cricket virus, and a scientist who was in tune with the sexual activity of her crickets. Next, a discovery based on a whole series of happy accidents.

Bob Ross would be proud. In the early 2000s, physician-scientist George Liu was studying a certain kind of Streptococcus bacteria known as type B. It’s the version behind pneumonia, blood infections, and meningitis.

He wanted to figure out what made this kind of Strep so dangerous to people. And to do that, he was specifically studying a certain toxin that the bacteria uses to punch holes into host cells. Liu was working with one strain of bacteria with the toxin, which had a pigment that turned it a deep, rusty red, and a mutant without it, which was a sort of bland white-ish color.

For a while, though, Liu wasn’t making much progress. Instead, he was struggling just to keep the bacteria alive, especially the mutant strain. And you can’t very well do experiments if you don’t have stuff to work with!

Thankfully, he soon figured out why, by using his nose. By chance, he smelled some residual bleach in the flasks he was using to grow the bacteria, which explained the mass cell death. Turns out that a labmate had kindly done the dishes, but needed to be more vigilant about rinsing the bleach away.

Now, Liu’s tests could have easily ended right there. Case closed. But he was also curious why the bleach seemed more effective at killing the white mutant cells.

He thought that maybe it was because they didn’t have any toxin in them. And then came the second happy accident. Around this same time, Liu’s mom reminded him to eat his colorful veggies, as many moms do.

But that actually gave him a new idea. The mutant cells couldn’t produce any toxins, but they also couldn’t produce that reddish pigment. So what if the toxin had nothing to do with it?

What if the pigment was protecting the bacteria instead? See, part of the reason colorful vegetables are so good for you is because they’re chock full of antioxidants, molecules that protect cells from damage. And those very molecules also give the foods their color.

So maybe the pigment in the regular cells was protecting them from the bleach. But it wasn’t clear why that would happen, either. Eventually, all the pieces fell into place when Liu noticed that the bleach used to clean the flasks contained the ingredient hypochlorite.

This is just the technical name for one type of bleach, but Liu was used to seeing it in scientific papers. He knew that, in your body, special white blood cells engulf bacteria and then wipe them out by flooding them with hypochlorite. After that, Liu went on to show that during an infection, strep uses its pigment, which is a carotenoid, similar to what’s in carrots and tomatoes, as a kind of shield.

This makes it harder for immune cells to destroy the bacteria. And because the mutant Strep didn’t have any pigment, they weren’t protected from the hypochlorite bleach. So by making the most of three chance encounters,.

Liu revealed a totally new reason why strep infections are so deadly. And his mom probably earned some bragging rights, too. Number 3: another serendipitous discovery in insects. 15 or so years ago, budding evolutionary biologist Liz Tibbetts was investigating the complex social structures of certain paper wasps.

These are social wasps that make nests out of chewed up wood. To draw conclusions about how the wasps interact, researchers in this line of work dot the backs of the insects with different colors of model airplane paint. With these labels, scientists can then put the whole colony together, turn on a video camera, and track each insect as they go about their lives.

One day, Tibbetts was reviewing a movie and realized she’d messed up:. She had missed painting the backs of two of the wasps. And at first, she was kinda bummed, since she figured she’d have to scrap the video and start all over.

But as she looked closer at the two paint-free wasps, she saw that each one had distinct markings on their faces. She could actually tell which one was which! And if she could do that, well, maybe the wasps could, too.

Nobody thought insects could tell each other apart, least of all visually. But once Tibbetts had the insight to ask whether it was there for a reason, she started checking out more wasp faces and found a remarkable amount of diversity. Some wasps had bright yellow eyebrows, while others had unique spots or other stripes and shapes.

To find out whether all those markings meant anything to the insects, she went ahead and gave some of them a makeover, painting on different features with a toothpick. And when she re-introduced the dolled up ones to the rest of the colony, fellow wasps lashed out and attacked them, no longer seeing them as friends. This showed not only that wasps were capable of recognizing faces, but also that the skill was an important part of the social glue that holds the colony together and helps it function.

OK, so you’ve probably heard at least a little about CRISPR-Cas9, the genome-editing tool scientists have been going gaga over in recent years. And we’ve definitely talked about it more than once here on SciShow. It’s basically a set of molecular scissors that we can precisely target to anywhere in DNA.

The system was originally found in bacteria as a way they fight off viruses. But scientists are learning how to use it to modify DNA sequences in other organisms. Including, potentially, us.

The Cas9 is the scissors part, it’s the protein that does the cutting. The thing is, though, it pretty much only cuts DNA, so it doesn’t work very well on RNA, the intermediate molecule your body makes before creating proteins. And that’s kind of a bummer, because scientists would love to also be able to edit RNA.

If they could do it, they might be able to treat specific RNA-based diseases, like a type of dementia, or fix things without touching the underlying DNA sequence. Well, the good news is, scientists might have just found a breakthrough. This year, a group of biological chemists at the University of Michigan uncovered a new Cas9 protein that acts on RNA, and it was totally unintentional.

They were working in their usual model system, a specific bacteria that causes meningitis, and were testing for the basic cutting ability of the protein. For a control group, they had incubated the protein with RNA. The whole point was that it wasn’t supposed to touch the RNA, while it would cut the DNA.

But time after time, the RNA was being sliced and diced as well. Eventually, the team realized what was happening, and that they had a dual DNA and RNA cutter on their hands. And other research teams are also beginning to report they’ve found similar things, although whether those were also happy accidents remains to be seen.

This next fortuitous discovery is an oldie but a goodie: the invention of the implantable pacemaker. In 1956, electrical engineer Wilson Greatbatch was trying to build a machine that could record heart rhythms. But in the course of putting the thing together, he put in the wrong transistor.

Transistors are circuitry components that can turn the flow of electrons on or off, like a switch. Greatbatch accidentally grabbed one that was too powerful for what he needed, and it made the device pulse about once every second. And he was stunned.

He recognized that the rhythm was the same as a heartbeat, and that the electric pulse could probably be used to snap unruly hearts back into step. Greatbatch then got to work trying to miniaturize his device so it could fit inside a human body. Two years later, he had a prototype working in a dog, and then the first human patient got one in 1960.

Thanks to that chance discovery, they’ve been changing lives ever since. And finally, a lab error that led to a more Earth-friendly plastic. A few years ago, IBM chemist Jeannette Garcia was trying to make a new plastic from three starter ingredients.

She was a little impatient and started heating two of the substances together while she went over to the scale to measure out the third. And when she returned, she found a white pellet attached to her flask. She struggled to get it out, so much so that she had to use a hammer to shatter the glass.

Although weirdly, the new plastic wasn’t hurt by the hammer. Now, Garcia could have tossed everything out. The intended experiment was a failure, and she had ruined some glassware.

She could’ve just chalked it up to her impatience and moved on. But instead, she was intrigued by the unusual strength of this new material. And additional experiments revealed the plastic to be not only super-strong, but also recyclable.

Which, in the world of plastics, is actually kind of a big thing. Part of the deal with high-strength plastics, otherwise known as thermosets, is that once they’re made and molded into a shape, they’re like that forever. You can’t melt them down to re-use them, which means you can’t recycle them.

But Garcia found that if she dunked the new plastic in sulfuric acid, it could be re-used. And the same research group found that a second plastic with the same type of chemistry can also self-heal, re-forming bonds if it’s cut. So, so much for mise en place, I guess.

Garcia’s lack of preparation turned out to be a boon, and opened up a whole new world of recyclable plastics. In each of these accidental discoveries, there was an element of chance. If Garcia hadn’t combined those two ingredients just so, or Greatbatch hadn’t pulled out the wrong transistor, nothing would have come of it.

And we wouldn’t be talking about them today. But what really ties them together is an openness to think about what’s right in front of them, to recognize something as being different, and interesting, and potentially important, and to ask questions about it. So, all you accidental discoverers-to-be out there, even when you make a mistake, stay curious.

And see where it takes you! Thanks for watching this episode of SciShow, and special thanks to our patrons on Patreon. You guys rock!

If you’d like to help us keep exploring discoveries like these, you can go to patreon.com/scishow. [♪ OUTRO].