touch-down PCR

[Timur Yarovinsky]

Hi,


On Thu, 16 Jul 1998, Thomas Eitinger wrote:
> could anybody give me a short definition/explanation for "touch-down
> PCR"

As I understand touchdown PCR you start cycling with high annealing
temperature (above melting point) and lower it for 0.5-1 degree each cycle
during first ~15 cycles. Using touchdown favors better proportion of
correctly amplified products if you had nonspecific amplification. 

See ref: Ault, GS et al. (1994) J Virol Methods 46, 145 and brochure "PCR
Protocols and Reference Guide" from Promega. 

Sincerely,

Timur Yarovinsky

University of Iowa