Microfluidic Tools for DNA Analysis - DNA Nanotechnology: From Structure to Function - page 133

Fig. 7.17 Multivolume digital PCR on radial SlipChip. Sample is loaded from the center and
after filling is rotationally slipped to isolate wells (Reprinted with the permission from Ref. [ 75 ].
Copyright 2011 American Chemical Society)

Fig. 7.18 Water-in-oil droplets for digital PCR applications (Reprinted with the permission from
Ref. [ 84 ]. Copyright 2011 American Chemical Society)

7.3.2 Sizing

Genetic variations can be divided into two parts: single-nucleotide polymorphisms
(SNPs) and structural variations, according to the number of bases that are mutated.
SNPs require single-base resolution which can be achieved by many means such as
sequencing, while variations more than 1 kb in size are referred to as the structural
variations [ 85 ]. Both SNPs and structural variations are relevant to phenotypic
diversity, evolution, as well as human diseases. Especially, the large-scale genomic
alteration, rather than SNPs, makes structural variations highly relevant to almost
all of inherited disorders, which increasingly attract much attention of researchers
recently [ 86 , 87 ]. Using human genome reference sequence(s) as the reference
[ 88 ], structural variations can be further divided into copy number variations,
insertions, deletions, inversions, translocations, and other complex rearrangements
of DNA segments (Fig. 7.19 ). They may alter the genome length (called unbalanced
changes) or not (called balanced changes). The balanced changes are often benign,
whereas unbalanced changes that lead to gain or loss of genetic materials are more
likely to have a phenotypic effect [ 85 ].