Answer:
2
Explanation:
If the sequence that you want to delete is flanked by different sequences, you will need 2 sgRNAs: one to produce the cut at the 5´ side, and other complementary at the 3´ site.
However, in the unlikely case in which both of the flanking sequences are almost the same ( more than a 90% of identity) or if it is a palindromic pattern, you can use the same sgRNA to guide the cuts.
Hope you luck!
