Heredity, Oldest Bread, Jupiter's Moons. July 20, 2018, Part 2

Have you ever taken a peek at your family tree? If you trace back along those branches, you might discover some long ago celebrities, kings, and philosophers among your ancestors. But what does it even mean to be “related” to an ancient queen when it’s hard to know what’s lurking inside our own DNA? It turns out even one generation back, the question of who we are gets made complicated. “We’re primed to think of our genomes as some kind of magical book. We just understand so little about genetics. Period.” says Carl Zimmer, author of the new book She Has Her Mother’s Laugh: The Powers, Perversions, and Potential of Heredity. Zimmer joins Ira to discuss Mendel’s Law, the history of eugenics, the power of CRISPR and the boundaries of what we understand of human heredity today.

Bread is a staple food today. You can find dozens of varieties at the supermarket—tortillas and pita, naan and focaccia, rye bread and wonder bread and baguettes too. Bread is so ubiquitous that it’s hard to imagine it was once a rare commodity, a labor-intensive specialty that could be made only by husking the seeds of wild grasses, hand-pounding and grinding them, then mixing the resulting flour with water and scorching on a hearth. Archaeologists working at a 14,000-year-old site in Jordan have now found evidence of an early bakery in the form of burned crumbs, similar to the ones at the bottom of your toaster. After analyzing the crumbs’ structure with a scanning electron microscope, the researchers were able to characterize the crumbs as the charred remains of a flatbread, similar to pita, baked with ingredients like wild einkorn wheat, barley, oats, and the roots of an aquatic plant similar to papyrus. They also determined that the crumbs predate the dawn of agriculture.

When Galileo first saw Jupiter through a telescope, he also discovered “stars” that would orbit around the planet in the night sky. While Galileo named them the Medicean stars—after his future patron Cosimo II de’ Medici—we know them today as Jupiter’s moons Io, Europa, Ganymede and Callisto. Since Galileo’s initial discovery, astronomers have found dozens more moons around Jupiter, and this week, researchers announced an additional 12 moons, bringing the total number up to a whopping 79.

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