Origin, a Genetic History of the Americas

Earth Faces A Global Heat Wave

Temperatures are higher than normal for much of the planet this week—and while the heat wave in Europe has had much of the attention, over 100 million Americans in 28 states were under extreme heat advisories this week.

Yasmin Tayag, a freelance science editor and writer based in New York, joins Ira to talk about the global heat wave and other stories from the week in science—including the president’s COVID diagnosis, an uptick in drug-resistant infections, and the question of whether previously uninfected people are “sitting ducks” when it comes to new COVID variants. They’ll also tackle some lighter topics, including new studies of how an elephant’s trunk works, and the genetics of how penguins came to prefer colder climates.

Genetics Suggest Indigenous People Arrived In Americas Earlier Than Some Thought

For years, grade school textbooks have told the story of how the Americas were populated by people crossing a land bridge from Asia and migrating in the safe havens between glaciers. In this version of history, its inhabitants arrived 13,000 years ago.

But that story needs an update, thanks to both new archaeological evidence, and the increasingly robust tools of genetic analysis—ancient genomes extracted from millennia-old human remains suggest a much longer history of people in the Americas, perhaps by thousands more years, and aligns with the oral histories of Native Americans and other Indigenous peoples. The genetic evidence also brings up new mysteries, including evidence of some groups of ancient peoples with no direct descendants today.

Producer Christie Taylor talks to University of Kansas anthropological geneticist Jennifer Raff, the author of Origin: A Genetic History of the Americas, about the growing evidence for the need to revise the history of the First Peoples. Plus, why researchers seeking to tell that story need to work directly with contemporary tribes to ensure that exploitative scientific practices of the past are not repeated.

Can Genetic Modification Help Plants Survive Climate Change?

Temperatures around the world are reaching all-time highs as major heat waves cause extreme weather and climate events. Earlier this year, temperatures in India and Pakistan soared to 120 degrees Fahrenheit, followed by months of unrelenting, unseasonably hot weather. A brutal heat wave is now moving across Europe, fueling devastating wildfires, and producing Britain’s highest temperature on record. Propelled by climate change, future heat waves promise to increase in frequency and intensity, posing a dangerous threat to human health.

But people aren’t the only ones at risk. Many plants—including essential food crops—struggle to survive as temperatures rise. When conditions heat up, a plant’s immune system can shut down, eliminating its defense mechanism. With key agricultural regions already experiencing record highs, global food supplies face potentially devastating consequences.

Ira talks to Sheng-Yang He about his research published in Nature last month that offers a potential solution—using gene editing to strengthen a plant’s defenses against increased temperatures.

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