The Pulse explores how the environment shapes biology. Turns out that influence goes deep, down to the molecular level — to the DNA of humans and animals.

Also heard on this week’s show:

• Davis Land speaks with a Houston mom about the stress of dealing with Hurricane Harvey — and the super simple coping exercise that researchers say might help.
• Author-illustrator Katrina van Grouw takes us on pigeon hunt to explain how humans are affecting animal evolution. Her book is Unnatural Selection.
• Mike Moscarelli offers a history lesson on our early theories about inherited traits — and the bedeviling mystery of redheads.
• Dana Farengo Clark, a genetic counselor at Penn Medicine, says her white-coat world has collided with those swab-your-cheek, spit-in-a-cup commercial DNA services.
• Eric Kmiec, director of the Gene Editing Institute at Christiana Care Health System, shares his hopes for CRISPR, that it could be used for better lung cancer treatment.