The MacBook Pro follows, with its prices going from $2,199 down to $1,999 for the 15-inch version (and from $1,499 for the 13-inch version down to $1,299). That's a break from traditional Apple pricing, where prices would remain the same generation over generation, with updated components adding value.
Restriction enzymes can also be used to generate compatible ends on PCR products. In all cases, one or more restriction enzymes are used to digest the DNA resulting in either non-directional or directional insertion into the compatible plasmid.
Like all enzymes, a restriction enzyme works by shape-to-shape matching. When it comes into contact with a DNA sequence with a shape that matches a part of the enzyme, called the recognition site, it wraps around the DNA and causes a break in both strands of the DNA molecule.