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Smart Amplifi cation Process Version 2
A rapid SNP detection system called smart amplifi cation process version 2 (SMAP
2) has been reported (Mitani et al. 2007 ). Because DNA amplifi cation only occurred
with a perfect primer match, amplifi cation alone was suffi cient to identify the tar-
get allele. To achieve the requisite fi delity to support this claim, the authors used
two new and complementary approaches to suppress exponential background DNA
amplifi cation that resulted from mispriming events. SMAP 2 is isothermal and
achieved SNP detection from whole human blood in 30 min when performed with
a new DNA polymerase that was cloned and isolated from Alicyclobacillus acido-
caldarius (Aac pol). Furthermore, to assist the confi guration of SMAP 2 assays,
software specifi c for SMAP 2 primer design was developed. With these new tools,
a high-precision and rapid DNA amplifi cation technology has become available for
pharmacogenomic research and molecular-diagnostics applications. A study has
confi rmed that PNA-SMAP2 combination has higher sensitivity and accuracy than
traditional sequencing methods or PCR and is suitable for the clinical diagnosis of
KRAS codon 12 mutations (Araki et al. 2010 ).
Zinc Finger Proteins
Zinc fi nger DNA-binding proteins (ZFPs) are the dominant class of naturally occur-
ring transcription factors in organisms from yeast to humans. ZFPs can effectively
detect small variations in DNA sequences and therefore may be used to detect SNPs
in clinical samples. ZFPs have the potential to eliminate the extensive manipulation
of patient DNA samples, reducing the time and cost, and increasing the accuracy of
diagnostic assays. Sangamo Biosciences intends to commercialize ZFPs for SNP
detection and DNA diagnostics in conjunction with partners engaged in the devel-
opment of SNP diagnostic technology or the manufacturing and marketing of clini-
cal diagnostics.
Mitochondrial SNPs
While autosomal nuclear DNA genes are confi ned to the nucleus, limited to two
copies per cell, the mitochondrial DNA (mtDNA) genes are distributed throughout
the cytoplasm and are present in numerous copies per cell. The mtDNA molecule
is relatively small containing 16,569 nucleotide pairs. There is growing evidence
that defects of mtDNA causes disease. Majority of these defects are due to point
mutations or rearrangements of the mitochondrial genome, while others, such as
mtDNA deletions, are autosomally-linked. More than 100 mutations of mtDNA
been associated with a striking variety of multisystem as well as tissue-specifi c
human diseases.
Mitochondrial SNPs (mtSNPs) constitute important data when trying to shed
some light on human diseases. Amongst the several methods reported for SNP
2 Molecular Diagnostics in Personalized Medicine