Extracting DNA from low-melt agarose gels

Tae Shin tshin at husc8.harvard.edu
Thu Jul 8 21:43:54 EST 1993

KARN at Butler.EDU writes:

>I wish to use low-melt agarose gels to clean up a PCR product of about 1 kb
>(+/- 0.2 kb) but would like to avoid the multiple extraction procedure 
>described in Maniatis.  My goal is to sequence the product so it must be
>relatively clean.  Anybody got an improvement on the Maniatis technique
>or must I haul out the phenol?
>Bob Karn

	I have a pretty good method, but you have to use regular agarose,
not the low-melting variant.

	1. Cut out your gel slice and put it in an eppendorf tube.
	2. Freeze the tube (and gel inside) in dry ice or liquid nitrogen.
	3. Let the tube warm up to room temperature.
	4. Spin the tube in a microfuge for 10'-15'.
	5. Siphon off and retain the supernatent.  This has the DNA in it.
	6. Add another equal volume of TE buffer to the remanents of the
		gel slice.  Repeat the process and add the supernatent to 
		the previous amount.
	7. Precipitate the DNA with NaOAc/EtOH.

T.B. Shin
tshin at husc8.harvard.edu

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