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Failure mode categories Failed wells were distributed into each category based on observational data taken during sequencing pipeline procedures and manual evaluation of electropherogram traces. |
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| Failure Mode |
Trace characteristic |
No. of sequencing reactions |
Percent of all failed wells (Q20 < 600) |
|
|
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| Blocked capillary |
Noisy or no data with a low signal intensity value (<100). Verified with capillary control results. |
64 |
5.5 |
| Low signal strength* |
Noisy or no data with a low signal intensity value (<100) that is very close to or falls below the instruments detectable limit. |
310 |
26.5 |
| Mixed clone w/ vector sequence |
Clean vector sequence followed by noisy data immediately after the cloning site. |
137 |
11.7 |
| Mixed clone, no vector sequence |
Noisy data throughout the trace with sufficient signal intensity. |
27 |
2.3 |
| Low signal to noise ratio |
Discernable sequence peaks with strong intensity background noise. |
22 |
1.9 |
| Excess Dye peaks |
Large dye front usually followed by noisy data. |
10 |
0.9 |
| Hardstop |
Abrupt end to good sequence. |
2 |
0.2 |
| Repetitive Sequence |
Long stretch of repetitive DNA sequence that is followed by slippage in sequence or noisy data. |
17 |
1.5 |
| Homopolymer stretch |
Long stretch of a single nucleotide followed by slippage in sequence or noisy data. |
99 |
8.4 |
| Poly A Tail |
Stretch of Ts (template A) followed by slippage in sequence or noisy data. |
484 |
41.3 |
| Total |
1172 |
100.0 |
|
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* Preliminary failure mode, further broken down to final failure modes in Table 2. | |||
Yang et al. BMC Genomics 2005 6:2 doi:10.1186/1471-2164-6-2 |
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