Learn about how quadruple-helix DNA could help us fight cancer; how diversity improves technology, with materials scientist Ainissa Ramirez; and how cats domesticated themselves.
Learn about how quadruple-helix DNA could help us fight cancer; how diversity improves technology, with materials scientist Ainissa Ramirez; and how cats domesticated themselves.
Quadruple-helix DNA exists - and it might be useful for fighting cancers by Cameron Duke
Additional resources from Ainissa Ramirez:
In True Feline Fashion, Cats Domesticated Themselves by Anna Todd
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Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/quadruple-helix-dna-is-a-thing
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 how quadruple-helix DNA could help us fight cancer; how diversity improves technology, with materials scientist Ainissa Ramirez; and how cats domesticated themselves.
CODY: Let’s satisfy some curiosity.
In school, you probably learned that DNA is a double helix: you know, that spiral ladder structure where the rungs are the A’s, T’s, C’s, and G’s that code for all of your traits. That by itself is impressive. But guess what? Quadruple-helix DNA also exists, and understanding exactly what it does might help us fight cancer.
Scientists have known about quadruple-helix DNA since the 1960s, but it wasn’t until 2013 that a group of scientists first identified quadruple-helix DNA in human cells. Quadruple-helix DNA mostly happens in sequences that are rich in G bases — that G stands for guanine. While G bases can form pairs with A, T, and C bases, it likes to form quartets with other G bases. Stacks of these quartets are what form quadruple-helix DNA, which is why these DNA strands are also called G-quadruplexes. Not only does it sound cool, but 4G was already taken, anyway.
Scientists don’t know exactly what G-quadruplexes do, but they are 100 percent confident that they don’t turn you into the Hulk. They know that because while G-quadruplexes are rare, they seem to form in human cells normally as the cells divide.
Learning about this is not just obscure theoretical work, either. Getting a grasp on the functions of G-quadruplexes might take our understanding of cancers to new levels. This is because as cancer cells divide, they tend to form a lot more G-quadruplexes than normal cells do.
Recently, scientists were able to spot G-quadruplexes as they interacted with proteins called DNA helicases [HEEL-lick-case]. These are the proteins that the cell uses to “unzip” its DNA as it is dividing. To spot this, researchers injected a chemical into living cells that causes G-quadruplexes to glow so they are easier to spot. They injected this dye into both normal cells and cells that couldn’t produce the DNA unzipping proteins. What they found is that the cells without the helicases produced more g-quadruplexes than the ones that didn’t. That suggests that DNA helicases are responsible for breaking down these strands of quadruple-helix DNA.
There’s still a long way to go before scientists figure out exactly what’s going on, but given the role that G-quadruplexes seem to play in cell division, understanding how to make drugs that can bind to these weird structures could potentially allow for the development of new cancer treatments.
You can't expect one person to know what everyone else needs. Yet a lot of the time, we expect one kind of person to create technology that works for all kinds of people. And that leads to technology with blind spots. Today, Ainissa Ramirez is back one last time to tell us some of the strange places those blind spots show up, and how more diversity in science and tech can make future technology better. Ainissa Ramirez is an award-winning scientist and science communicator, and author of the book "The Alchemy of Us: How Humans and Matter Transformed One Another." We started by asking her: do we know how technology is transforming us right now?
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Again, that was Ainissa Ramirez, an award-winning scientist and science communicator, and author of the book "The Alchemy of Us: How Humans and Matter Transformed One Another." You can find a link to pick it up in today's show notes.
Cat owners know that cats train people and not the other way around. So, it may come as no surprise to learn that kitty DNA reveals that humans didn’t actually domesticate cats — cats domesticated themselves. Even more surprising: your fuzzy couch companion doesn’t have many genetic differences from a stone-cold wildcat.
That’s according to a comprehensive survey of cat genetics performed back in 2017. Researchers analyzed the DNA of more than 200 cats spanning the last 9,000 years — including cat remains from ancient Romania and ancient Egypt — along with modern African wildcats. They found that our domesticated feline friends come from one of two major lineages. The initial line of ancestors began as early as 4400 B.C.E. somewhere between Europe and southwest Asia. These cats had probably followed their rodent prey to farming communities about 8,000 years ago — and because their rodent hunting was a win-win for both cats and humans, they hung around.
The second lineage probably began around 1500 B.C.E. when Egyptian cats successfully spread throughout the "Old World." The researchers think these cats probably had traits that made them likeable to humans, like sociability and tameness. The researchers didn’t find a distinct change in the cat’s genetic makeup until the Middle Ages, which is the first time Tabby cats with blotched or striped coat markings show up. These markings probably got their start in the Ottoman Empire in Southwest Asia, then became common in both Europe and Africa. The coat only became associated with domesticated cats in the 18th century. House cats weren’t even bred for specific traits until the 19th century.
Why so late? Probably for the same reason we rarely train cats to fetch. We rely on dogs for specific tasks, so humans quickly figured out they could breed them to be better at those tasks. Cats, not so much. According to the lead researcher, breeding wasn’t necessary because cats were already perfect. I agree. Not that I’m biased or anything.
Let’s do a quick recap of what we learned today
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CODY: Today’s stories were written by Cameron Duke and Anna Todd, and edited by Ashley Hamer, who’s the managing editor for Curiosity Daily.
ASHLEY: Scriptwriting was by Cody Gough and Sonja Hodgen. Today’s episode was produced and edited by Cody Gough.
CODY: Join us again tomorrow, when we let the cat out of the bag! ...or the BATHROOM… to learn something new in just a few minutes.
ASHLEY: And until then, stay curious!