Question

True or False - Digestion of genomic DNA with EcoRI (6-base cutter) will yield average size fragments of 256 bps

Answer 1

Correct ans will be FALSE..

Explanation: As we know, the EcoR1 is a restriction endonuclease type II which means it cuts the DNA at internal side at exact sequence where cut is required no upstream or downstream like other endonuclease.

EcoR1..5' G/AATTC 3'

3 'CTTAA/G 5' ('/'symbol represents cut side)

Normally, DNA contain 4 base pair A,T,G,C and we assume the frequency of bases are in random distribution if 50% GC or AT present.so the probability of frequency of base pair of 4 base pair recognising sequence will be (4)4=256..means after 256 bp size fragments will get and the same sequence frequency will repeat after every 256 bp.

Here, in case of EcoR1 a six base cutter means it only recognise and cut at 6 bp sequences which average size fragments will be (4)6= 4096 bp.

So,the Ans will be average fragments size will be 4096 base pair not 256 bp (It will be for 4bp cutter)