In one of the most classic scenes in "The Princess Bride," the sword fighter Inigo Montoya, played by Mandy Patinkin, monologues to the Dread Pirate Roberts (Cary Elwes) about why he is so devoted to ...

Just because a trait is dominant does not mean it is common. Each color represents different levels of light eyes. Blue=80%+, teal=50-79%, olive=20-49%, brown=1-19%, black=none. Image courtesy of Dark ...

But even these “basic” genetic equations can get complicated, and some dominant traits work a little differently. If genes are controlling a process where all of the alleles need to be on the same ...