
Figure 31
Phasing and Prephasing
A
Read with a base that is phasing
B
Read with a base that is prephasing.
RTA2 corrects the effects of phasing and prephasing, which maximizes the data quality at every cycle
throughout the run.
Base Calling
Base calling determines a base (A, C, G, or T) for every cluster of a given tile at a specific cycle. The MiniSeq
System uses 2-channel sequencing, which requires only 2 images to encode the data for 4 DNA bases, 1
from the red channel and 1 from the green channel.
Intensities extracted from an image compared to another image result in 4 distinct populations, each
corresponding to a nucleotide. The base calling process determines to which population each cluster
belongs.
Figure 32
Visualization of Cluster Intensities
Base
Red Channel
Green
Channel
Result
A
1 (on)
1 (on)
Clusters that show intensity in both the red and green channels.
C
1 (on)
0 (off)
Clusters that show intensity in the red channel only.
G
0 (off)
0 (off)
Clusters that show no intensity at a known location.
T
0 (off)
1 (on)
Clusters that show intensity in the green channel only.
Table 1 Base Calls in 2-Channel Sequencing
Clusters Passing Filter
During the run, RTA2 filters raw data to remove clusters that do not meet the data quality threshold.
Document # 1000000002695 v02 Material # 20014309
For Research Use Only. Not for use in diagnostic procedures.
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MiniSeq System Guide