Editor’s note: A version of this story appeared in CNN’s Wonder Theory science newsletter. To get it in your inbox, sign up for free here . CNN  —  Picture the Sahara, and an inhospitable landscape of endless sand dunes and barren rock comes to mind. That’s largely the case today, but 7,000 years ago the vast desert was an altogether different place: a verdant world of trees and rivers and home to megafauna such as hippos and elephants. Over the past decades, scientists have gleaned details of

Tag-uri: DNA