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 halfback position is one of the more glamorous positions on the field, and is commonly viewed as a requirement for a team's success. Sometimes the halfback can catch the ball from the backfield on short passing plays as he is an eligible receiver. Occasionally, they line up as additional wide receivers.