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 ...

Genetics are extremely complicated—so complicated that having an extra finger or toe, for example, is exceedingly rare ...

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 ...