The GOI was isolated from human chromosomal DNA by PCR. The GOI (1.7kb) was introduced into a TA cloning vector (Fermentus), then double digested the TA clone & pGL3 vector by KpnI-HF & HindIII-HF and ligated both. I got colonies, but, the insert was not found after digestion check, though a band was found at the level of liner pGL3. How will I solve this problem?