Learn about what Neanderthal genes might be doing in your DNA; the person who invented “Do, Re, Mi” notation, or solfège; and how photosynthesis killed off 99 percent of life on Earth during the the Great Oxygenation Event.
Learn about what Neanderthal genes might be doing in your DNA; Guido d’Arezzo, the 11th-century Benedictine monk who invented “Do, Re, Mi” notation, or solfège; and how photosynthesis killed off 99 percent of life on Earth during the the Great Oxygenation Event.
How Neanderthal genes might be influencing your skin, mood, and immune system by Andrea Michelson
"Do, Re, Mi" Notation Was Invented by One Man 1,000 Years Ago by Reuben Westmaas
The time that photosynthesis killed off 99% of life on Earth by Cameron Duke
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Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/what-neanderthal-genes-are-doing-in-your-dna-the-time-photosynthesis-killed-nearly-all-life-on-earth-and-the-inventor-of-do-re-mi-notation
CODY: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from curiosity-dot-com. I’m Cody Gough.
ASHLEY: And I’m Ashley Hamer. Today, you’ll learn about what Neanderthal genes might be doing in your DNA; the person who invented “Do, Re, Mi” notation; and that time photosynthesis killed off 99 percent of life on Earth.
CODY: Let’s satisfy some curiosity.
Before you go calling someone a Neanderthal, you might want to take a look at your own DNA. You might find that you have more Neanderthal in you than you’d think. That’s because about 50,000 years ago, our ancestors actually mated with the other ancient hominins. And this was no casual fling — our species were interbreeding enough that pieces of Neanderthal DNA still exist in some people’s genomes today.
Scientists discovered evidence of human-Neanderthal relations shortly after they first sequenced the Neanderthal genome in 2010. They found that modern humans of Eurasian descent could trace about 2 percent of their DNA back to Neanderthal origins. Since this discovery, scientists have been trying to understand how much the gene variants we’ve inherited from Neanderthals affect who we are today. They haven’t found any variants that have a unique effect the way they have with many human genes. But they have been able to identify some associations between Neanderthal DNA sequences and the expression of certain characteristics.
By studying the genomes of more than 100,000 modern British people, scientists found that people with Neanderthal ancestry were paler and more likely to get sunburnt. It’s unclear how this gene variant was helpful for ancient humans, but we do know that Neanderthals were well-adapted for cold weather — they had short, stocky builds and wide noses — so they probably weren’t getting too much sun.
The same study also found an association between Neanderthal gene variants and characteristics related to mood, like loneliness and low enthusiasm. These findings line up with an earlier study linking Neanderthal variants to a higher risk for depression and addiction. It’s possible that the genetic predispositions that would make someone depressed in a modern environment were somehow beneficial to humans in an ancient environment.
Other aspects of Neanderthal DNA have more obvious advantages. A recent study at the University of Arizona found that one-third of beneficial Neanderthal gene variants have to do with how the immune system responds to viruses. The Neanderthals had built up immunity to their local diseases for a few millennia before our ancestors arrived in Eurasia. Once Neanderthals and humans, uh, “got to know each other,” they passed that immunological advantage on to their offspring.
So thanks to adaptation, natural selection, and some not-so-picky mating preferences, ancient humans inherited a number of Neanderthal characteristics that are still reflected in some people’s genes today.
Have you ever heard of solfège? Scratch that — you have. You just might know it better as "Do, Re, Mi, Fa, Sol, La, Ti, Do." It’s a musical system where every note is given its own syllable. But who in the world came up those syllables? Well it wasn’t Julie Andrews, I’ll tell you that much. Let me introduce you to Guido d’Arezzo. [GWEE-doh dah-RETZ-oh]
Guido d’Arezzo was an 11th-century Benedictine monk who needed an easy way to memorize hymns. See, there was no such thing as written music back then. If you were a choirboy in a monastery, you’d have to learn every hymn by following along with your conductor as he played each note one by one. And then you'd have to remember that exact hymn for years, even as you memorized more musical pieces. And if you didn’t perform a hymn for a while? Well, good luck remembering it. As a result, it could take you 10 years to learn all the hymns you needed to know to become a choir singer. It was...less than ideal.
Guido d'Arezzo was in charge of training the singers at the city's cathedral school. At his last monastery, he was exposed to an early form of musical notation. He spent his time at this new job building on it, eventually developing a four-line method of writing music that’s similar to what we still use today. But singers still needed to learn how to sightread this new music. So Guido looked for some verbal reminder he could use to help the singers remember the pitch of each note.
The hymn "Ut queant laxis" [oot KAY-ahnt LOCK-cease] fit the bill. Every line of the hymn starts one pitch higher than the last, making it a sort of mnemonic device. Guido just placed the first syllable of each line of the hymn on every pitch of the musical scale, which had just six notes at the time. The result was the following: "Ut, Re, Mi, Fa, Sol, La."
Over time, the scale evolved and the syllables were tweaked to be more musical and easy to remember. Eventually, it turned into the “Do, Re, Mi, Fa, Sol, La, Ti, Do” that we know today. Music students everywhere thank you, Guido.
Plants are great, aren’t they? They basically give us every bit of air we breathe, bite of food we take, and lush, green landscape we post to Instagram. That’s all thanks to photosynthesis, the method they use to turn sunlight, water, and CO2 into oxygen and energy. But photosynthesis hasn’t always been the good guy — it has a dark past. Like, oh, that one time it wiped out most of the life on Earth. Let me tell you about the Great Oxygenation Event.
If you traveled 2.5 billion years back in time, Earth would appear to be devoid of life — but the oceans would actually be swimming with it. The entire population of our planet at the time consisted of microbial organisms. There was no oxygen, but those microbes didn’t mind. They were anaerobic, which means that they metabolized their food without oxygen. Things went on this way for 1.4 billion years. Life was good.
Then, some of those microbes evolved the ability to perform photosynthesis. These were the cyanobacteria, sometimes called blue-green algae. Those colors have a purpose: blue is the color of phycocyanin [ˌfīkōˈsīənən / FYE-coe-SYE-ah-ninn], which helps absorb light, and green is the color of chlorophyll, which can both absorb and harvest energy from light. One byproduct of photosynthesis is oxygen, and these first photosynthetic bacteria released a lot of it. This was a very bad thing for the rest of the life on Earth. That’s because oxygen is very reactive — that’s why it oxidizes metal and fuels fires. Long story short, it was toxic for anaerobic bacteria at the time, and they began dying off anywhere oxygen became common.
Oh, but that wasn’t the end of it. This set off a chain reaction of mass extinction. See, methane was an incredibly common gas at the time, and when it reacted with the oxygen, it flooded the atmosphere with CO2. Because methane is a more potent greenhouse gas than CO2, atmospheric temperatures cooled. This led to a massive glaciation event that wiped out a ton of life — including a lot of the cyanobacteria that caused this mess in the first place. The Great Oxygenation Event ended up being the first of Earth’s five mass extinctions. All that from a little photosynthesis!
Still, life continued, just a little differently. Microbes that could use oxygen became much more common in the new oxygen-rich atmosphere and, eventually, gave rise to the oxygen-dependent life we have today. The lesson here? Don’t underestimate plants. They’ll wipe out life on Earth in a second and not even apologize for it.
Let’s do a quick recap of what we learned today
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CODY: Today’s stories were written by Andrea Michelson, Reuben Westmaas, and Cameron Duke, and edited by Ashley Hamer, who’s the managing editor for Curiosity Daily.
ASHLEY: Scriptwriting was by Cody Gough and Sonja Hodgen. Curiosity Daily is produced and edited by Cody Gough.
CODY: Join us again tomorrow to learn something new in just a few minutes.
ASHLEY: And until then, stay curious!