PROVIDENCE, Rhode Island, Aug. 21 -- Brown University posted the following news: * * * Extinct human relatives left a genetic gift that helped people thrive in the Americas * PROVIDENCE, R.I. [Brown University] -- A new study provides fresh evidence that ancient interbreeding with archaic human species may have provided modern humans with a genetic variant that helped them adapt to new environments as they dispersed across the globe. The study, published in Science, focused on a gene known  more