Path: utzoo!attcan!uunet!bionet!mbcr.cam.ac.uk!mje2 From: mje2@mbcr.cam.ac.uk (Martin Evans) Newsgroups: bionet.molbio.methds-reagnts Subject: (none) Message-ID: Date: 11 Jul 90 16:28:50 GMT Sender: daemon@genbank.BIO.NET Lines: 35 Reply to Sinclair's message re PCR machines ----- Begin Included Message ----- From mje2 Wed Jul 11 13:40:42 1990 From: Martin Evans Date: Wed, 11 Jul 90 13:40:41 BST To: mje2 Status: R In reply to the coments about PCR using the THERMAL REACTOR from Hybaid. As I am one of the inventors of the method used in this machine I must declare a possible bias BUT there is absolutely NOTHING wrong with the no-lid design. There is an insulating sheet of platic above the metal block and you will find BY ACTUAL TEST and MEASUREMENT that the temperature of the tube contents are very accurately controlled. A feature of this design and one which we used to develop it is that we measure the tube contents by thermocouple. If - as I have done _ you do a plot of the tube temperatures in a cycle you will find quite surprising and alarming overshoots and undershoots occuring in machines of repute from other manufactures. These hidden "features" may well explain some of the apparent differences in performance of different machines. If you accurately reproduce the temperature profiles from one machine on another (as you can with some of ours) you will find identical performance of the reaction as might be expected. Readers may like to know that as well as the presently licensed Hybaid THERMAL REACTOR the original design and newer developments of the INTELLIGENT HEATING BLOCK are still available from Genesys Instruments Ltd - through Cambio ... phone 0223-66500. Martin Evans.