User manual

38 | Droplet Digital
™
PCR Applications Guide
Fig. 4.1. Discrimination between consecutive CN states is more difficult at higher order copy numbers.
Fig. 4.2. ddPCR measurements of MRGPRX1 copy numbers across seven Coriell DNA samples.
Copy Number Variation Analysis
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Copy number, N
Copy number resolution: N vs. N–1, %
100
90
80
70
60
50
40
30
20
10
0
The massive partitioning of a CNV Droplet Digital
™
PCR (ddPCR
™
) reaction across
up to 20,000 droplets enables the fine quantitative discrimination required to resolve
consecutive copy number states beyond CN 3. This is due to the high precision of the
ddPCR concentration measurement and the absolute nature of the measurement. For
example, a 20% difference in target concentration between a CN 5 vs. CN 6 sample can
be reproducibly resolved using ddPCR (Figure 4.2). This discrimination is both a function
of concentration differences between consecutive CN states, as well as the amount of
DNA assayed per well.
11994 18507 18502 19221 19205 18916 19108
Sample
Copy number
7
6
5
4
3
2
1
0
2.89
4.79
5.69
0.992
2.04
3.98
2.02