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.
Split end (X or SE): A receiver on the line of scrimmage, necessary to meet the rule requiring seven such players at snap. Where applicable, this receiver is on the opposite side of the tight end. The split end is farthest from center on his side of the field.