Table 2 Comparison of first-, second-, and third-generation genomic sequencing.
| Â | First generation | Second generation | Third generation |
|---|---|---|---|
Fundamental technology | Size-separation of specifically end-labeled DNA fragments | Wash-and-scan SBS | Single molecule real time sequencing |
Resolution | Averaged across many copies of the DNA molecule | Averaged across many copies of the DNA molecule | Single DNA molecule |
Current raw read accuracy | High | High | Lower |
Current read length | Moderate (800-1000 bp) | Short (generally much shorter than Sanger sequencing) | > 1000 bp |
Current throughput | Low | High | High |
Current cost | High cost per base, Low cost per run | Low cost per base, High cost per run | Low cost per base, High cost per run |
RNA-sequencing method | cDNA sequencing | cDNA sequencing | Direct RNA sequencing |
Time to result | Hours | Days | < 1 day |
Sample preparation | Moderately complex, PCR amplification is not required | Complex, PCR amplification is required | Various |
Data analysis | Routine | Complex (due to large data volumes & short reads) | Complex |
Primary results | Base calls with quality values | Base calls with quality values | Base calls with quality values |