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.
Since the 1970s, restriction enzymes have had a very important role in recombinant DNA techniques, in both the creation and analysis of recombinant DNA molecules. The first restriction enzyme was isolated and characterized in 1968, and over 3,400 restriction enzymes have been discovered since. Of these enzymes, over 540 are currently commercially available. Nomenclature and Classification