ERRATUM: PFGE to separate 20-50 kb

[Andrei Popov]

Hello everybody,
recently there was a posting where it was asked how to separate
DNA fragments in the range of 20 to 50 kb. I replied to this thread 
saying that PFGE did not work for these sizes; as far as I can remember nobody came up 
with concrete suggestions. Since then I have been  faced with the same problem; I tried
several conditions, and have found one set of parameters that works.

Here it is:

1.5 % agarose in 0.5xTBE
3.5 C- temperature of the cooling waterbath
Voltage: 200 V
Switching times: 1s-     8 hrs
                            1.5s- 8 hrs
                            2s-     12 hrs
These conditions give a separation range between 5 and 50 kb, 
and the migration distance between 23kb and 48kb is about  2.5 cm.

best wishes


Andrei