Tk:E. coli cut sites

• CTAG sequences in the E. coli genome are rare.
• SpeI cut sites in the E.coli genome: 74
• XbaI cut sites in the E. coli genome: 40

• PstI cut sites in a 300Kbp region of the E. coli genome: 79
• Average length of PstI fragment: 300K/79 = 3800
• We would expect the average length of a double cut XbaI / PstI fragment to be about 1900 bp, and there to be about 40 different ones.
• Likely there are a few with order of 100 bp length

• EcoRI cut sites in a 300Kbp region of the E. coli genome: 42, but 18 are methylation inhibited. 24 are left actually cut.
• Average length of EcoRI fragment: 300K/24 = 12500
• We would expect the average length of the double cut EcoRI / SpeI to be about 6250 bp, and there to be about 79 of them.
• Likely there are a few with order of 80 bp length