- Course Introduction
- 01: Evidence & DNA
- 02: Forensic Biology
- 03: DNA Extraction & Quantitation
- 04: DNA Amplification
- 05: Amplified DNA Product Separation
- 06: STR Data Analysis & Interpretation
- Data Troubleshooting
- Data Interpretation & Allele Calls
President's DNA Initiative
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Advancing Justice Through DNA Technology
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Advancing Justice Through DNA Technology
DNA Analyst Training
Dye Blobs
Home > STR Data Analysis & Interpretation > Data Troubleshooting > Spurious Peaks > Dye Blobs
Disassociated primer dyes, more commonly referred to as dye blobs, are fairly common in STR analysis. While it isn’t entirely understood why dye blobs occur, evidence suggests that the fluorescent dye tags attached to the primers begin to break down over time.01 Disassociated primer dyes can show up in the sample analysis range and can mask true data. Dye blobs are usually wider than real peaks and are typically only seen in one color. By following the manufacturer’s specifications for storage of amplification kits, problems with disassociated primer dyes can be avoided.
If problems persist, the sample can be re-amplified or a filter unit clean-up step (e.g. link to Microcon® 100) can be performed. Amplified fragments of DNA will attach to the membrane while the disassociated primer dyes pass through the membrane and are filtered out of the sample.
