Practice question

Serial Analysis of Gene Expression quantifies transcript abundance using short diagnostic tags. After isolation of messenger RNA and synthesis of biotinylated complementary DNA, tags are released using an anchoring enzyme. The ditag formation and subsequent release of informative tags depend on a tagging enzyme that cuts at a defined distance away from its recognition site. BsmFI is a type IIS restriction endonuclease recognizing 5 prime GGGAC and cleaving 10/14 nucleotides downstream, generating 12 base tags including 4 bases of overhang. These tags are ligated, amplified, and sequenced to infer expression profiles quantitatively.