Appeal No. 95-3606
Application 07/827,691
templates than were PCRs with dGTP alone” (Innis II, p. 56,
first five lines; emphasis added). In our view, Innis II
neither expressly states nor reasonably suggests that PCRs
with c dGTP are more efficient than PCRs with mixtures of7
c dGTP and dGTP. To the contrary, Innis II teaches that “PCR7
(including asymmetric PCR) with c dGTP is as efficient as it7
is with dGTP for most templates, and for difficult templates,
is vastly superior to PCR with dGTP alone” (Innis II, p. 58,
first full sentence) and proffers PCR with a 3:1 c dGTP: dGTP7
mixture as the preferred example of PCR with c dGTP (Innis II,7
p. 55). Moreover, Innis II provides good reasons why persons
having ordinary skill in the art reasonably would have
preferred to use a mixture of c dGTP and dGTP in a PCR7
reaction mixture over c dGTP substantially free of GTP and7
dGTP, (1) “dGTP is necessary for visualization of the product
by ethidium staining” (Innis II, p. 58), and (2)
“incorporation of c dGTP during PCR can interfere with7
subsequent digestion by some enzymes” (Innis II, last para.,
second sentence).
Accordingly, we find no motivation whatsoever in the
combined prior art teachings, as a whole, to use c dGTP7
substantially free of GTP and dGTP during PCR over a 3:1
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