heteroplasmy of cloning vectors

"Alexander Kraev" bckraev at aeolus.ethz.ch bckraev at wawona
Sat Mar 4 06:26:07 EST 1995

In article <D4vEHG.Krn at info.swan.ac.uk>, G Jenkins writes:
>This may be a stupid question but it occured to me this week whilst I
>was trying to clone a PCR product. Is it possible for transfomed cells 
>to be heteroplasmic, i.e. to contain different species of plasmid perhaps
>one type with an insert and one without? 

Rather more typical is that your colony is contaminated with another one,
that grew close on the plate. If you want to be sure, re-streak your cells
to get well-separated colonies and isolate DNA from those. A still safer way
is to re-transform about 1 ng of the miniprep DNA and plate dilutions so as
to get less than 100 colonies on a plate ( they will be well separated ). It
is a rather unlikely case that your cell received more than one plasmid upon
transformation, unless you exceeded recommended DNA to cells ratio ( less than
10 ng per 200 ul  cells). Cheers,
Alexander Kraev, Ph.D.                 Internet: bckraev at aeolus.ethz.ch
Lab. of Biochemistry III               Phone: 0041-1-632-31-47
Swiss Federal Institute of Technology  FAX:   0041-1-632-12-13
CH-8092 Zurich
"Some ideas are obscure not because they are complex, but because they 
 are excluded from our circle of comprehension" - Kozma Prutkov

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