SNP genotyping is the measurement of genetic variations of single nucleotide polymorphisms (SNPs) between members of a species. It is a form of genotyping, which is the measurement of more general genetic variation.
On most plays, the center will snap the ball directly into the quarterback's hands. In a shotgun formation, the center snaps the ball to the quarterback lined up several yards behind him.
The location of the tackle box depends on where the line of scrimmage is for a given play, as well as where on that line the ball is marked for the snap. The dimensions of the tackle box dictate much of what the offense can and cannot do during a play. For example, the quarterback must either cleanly hand off, pitch, pass or run with the ball while he is standing within the tackle box.