Skulls show New World was settled twice: study

Two distinct groups from Asia settled in the New World and not one single migration as suggested by previous genetic studies, experts said Monday after comparing the skulls of early Americans.

Inbreeding detrimental for survival

Biologists have long known that inbreeding can be detrimental. Inbreeding results in less genetic variation, making species more vulnerable if changes occur that require them to adapt.

page 1 from 10