Q: PCR cloning from cDNA library

[Jinling Xie]

Hi, Dear netterrs,
    I've used PCR to amplify a fragment from cDNA library. The 
primers are designed according to the known partial sequence.
At first, I got PCR products at expected size.  Then I cloned 
them into TA cloning vector to analyze sequences. So far the 
sequences I got don't overlap with this known partial sequence.
This partial sequence is also amplified from the same library
by PCR. I used one T7 or Sp6 primer to amplify this 5'or 3'fragment
, another primer is from this known sequence. Are those PCR products
are non-specific? Anybody out there has any idea about this, would
you please reply me this account? I would appreciate it.


Jinling Xie