Appeal No. 2006-3207 Page 4
Application No. 09/565,191
DISCUSSION
The Claims
Appellants claim their invention as a kit and a composition. There are four
independent claims, and Appellants describe the subject matter of each. However, they
do not separately argue their patentability. Claim 61 is representative and reads:
A kit comprising two or more PNA probes wherein, the first PNA
probe is labeled with a detectable moiety and comprises a sequence
complementary to a target sequence and the second PNA probe is an
unlabeled or independently detectable probe comprising a sequence
complementary to a non-target sequence wherein the target and non-
target sequences consist of a single point mutation as compared to the
other.
As defined, PNA probes differ from oligonucleotide probes in that they are “non-
naturally occurring polyamides,” Specification at 5, and have different backbones and
ionic charge, with PNA being uncharged. Id. at 8. Due to these differences, “PNA
binds to its complementary nucleic acid more rapidly than nucleic acid probes bind to
the same target sequence” and “the stability of the PNA/nucleic acid complex is higher
than that of an analogous DNA/DNA or RNA/DNA complex.” Id. at 9.
As described in the specification, Appellants affix the target DNA molecules on a
solid surface, e.g., a nylon membrane, and then probe these molecules with both
labeled PNA complementary to the mutant DNA and unlabeled PNA complementary to
the wild-type DNA thereby suppressing non-specific binding to the wild-type DNA by the
labeled probe. According to Appellants, using this technique yields “dramatic
improvement in the signal to noise ratio for the hybridization assay.” Id. at 44-45.
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