Genome Traces, Beavers and Wildfire, Halloween DIY, Volcanoes. Oct 22, 2021, Part 2

The Ancient Neanderthal Traces Hidden In Your Genome Just how much of your genome is uniquely human? It turns out the number of genetic components in the human genome that trace back only to modern humans, and not to other human lineages or ancient ancestors, are surprisingly small. In a paper published recently in the journal Science Advances, researchers estimate the uniquely human portion of the genome as being under two percent.  Many of the genes thought to be strictly connected to modern humans appear to relate to neural processes. However, traces of genes from Denisovans and Neanderthals can be found scattered throughout the genome—including strong Neanderthal genetic signals in parts of the genome dealing with the immune system.Ed Green, a professor of biomolecular engineering at the University of California Santa Cruz and one of the authors of that paper, joins SciFri’s Charles Bergquist to talk about the study, and what can be learned by this approach to studying our genetic code.     Beavers Build Ecosystems Of Resilience Deep in the Cameron Peak burn scar, nestled among charred hills, there’s an oasis of green—an idyllic patch of trickling streams that wind through a lush grass field. Apart from a few scorched branches on the periphery, it’s hard to tell that this particular spot was in the middle of Colorado’s largest-ever wildfire just a year ago. This wetland was spared thanks to the work of beavers. The mammals, quite famously, dam up streams to make ponds and a sprawling network of channels. Beavers are clumsy on land, but talented swimmers; so the web of pools and canals lets them find safety anywhere within the meadow. On a recent visit to that patch of preserved land in Poudre Canyon, ecohydrologist Emily Fairfax emphasized the size of the beavers’ canal network. “Oh my gosh, I can’t even count them,” she said. “It’s a lot. There’s at least 10 ponds up here that are large enough to see in satellite images. And then between all those ponds is just an absolute spiderweb of canals, many of which are too small for me to see until I’m here on the ground.” The very infrastructure that gives beavers safety from predators also helps shield them from wildfire. Their work saturates the ground, creating an abnormally wet patch in the middle of an otherwise dry area. Dams allow the water to pool, and the channels spread it out over a wide swath of valley floor. Fairfax researches how beavers re-shape the landscapes where they live. Across the West, she’s seen beaver-created wetlands survive wildfires. Ira chats with Fairfax and KUNC's Water in the West reporter Alex Hager about how beavers are creating wetland oases that are surviving the West's new megafires.       DIY Halloween Hacks Trying to liven up your ghosts and goblins this Halloween? In this archival segment from 2013, Windell Oskay, cofounder of Evil Mad Scientist, shares homemade hack ideas for a festive fright fest, from LED jack-o’-lanterns, to 3D printed candy, to spine-chilling specimen jars.      The Burn Of Volcanic Beauty This week, Mount Aso, a volcano in Japan, erupted—spewing clouds of ash and smoke, but fortunately bringing no reported injuries. Meanwhile, on the island of La Palma, the Cumbre Vieja volcano has been erupting for over a month now, causing destruction and evacuations on the island, and dramatically changing the island’s coastline.  Robin George Andrews, author of the upcoming book Super Volcanoes, joins Ira to talk about the terror—and wonder—of volcanoes, and why their behavior can be so enigmatic to humans.   Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

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