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TA cloning -- funny sized bands - (Oct/22/2004 )

hi all

please help me with this problem i face when i use the TA cloning kit.
I PCR my 2.4kb insert and i set up a 20 min ligation with the TA vector.I got 3 white colonies on my plate but whn i do a plasmid prep , the bands i got in 2 clones correspond to around 2kb(insert) and the 3rd clone about 3.9kb (which is the size of the TA vector)

Why are these colonies white in color?
plz help me




Did you cut your plasmid before running the gel? If not, supercoiled plasmid has different migration rate from linerized plasmid, and doesn't match your DNA size marker.

You can verify if the plasmid contains an insert by restriction digestion or PCR.