Sequencing (all)

Elevate Your Research: Exploring the Power of 8-Dye STR Chemistry with the Spectrum Compact CE System

Posted on by Promega

In genetic research, staying at the forefront of technology is crucial. The latest breakthrough in human identification comes in the form of 8-dye Short Tandem Repeat (STR) chemistry. This innovation promises unprecedented precision and accuracy in DNA analysis, revolutionizing the way we approach genetic studies. In this blog post, we’ll delve into the world of 8-color chemistry and explore how it seamlessly integrates with the game-changing Spectrum Compact CE System.

Understanding 8-Dye STR Chemistry

The introduction of 8-dye chemistry expands the capability of STR analysis, enabling researchers to analyze more DNA markers with smaller amplicons, providing more robust data from degraded or inhibited DNA samples.  The performance of the 8-color dye chemistries from Promega on the Spectrum Compact CE System is sensitive, with both chemsitries (PowerPlex® 35 GY System and the upcoming PowerPlex® 18 E System) producing 100% profiles from their suggested inputs down to as little as 62.5 pg of DNA. The 18E system produced 100% profiles down to 31.25 pg of input DNA with minimal signal bleed through and low system noise.

Table showing percent STR profiles generated with decreasing input DNA using the PowerPlex 35GY or PowerPlex 18 E chemistry on the Spectrum Compact CE System
Table showing percent profiles generated with decreasing input DNA using the PowerPlex® 35GY or PowerPlex® 18E chemistry on the Spectrum Compact CE System.
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Better NGS Size Selection

Posted on by Darcia Schweitzer

One of the most critical parts of a Next Generation Sequencing (NGS) workflow is library preparation and nearly all NGS library preparation methods use some type of size-selective purification. This process involves removing unwanted fragment sizes that will interfere with downstream library preparation steps, sequencing or analysis.

Different applications may involve removing undesired enzymes and buffers or removal of nucleotides, primers and adapters for NGS library or PCR sample cleanup. In dual size selection methods, large and small DNA fragments are removed to ensure optimal library sizing prior to final sequencing. In all cases, accurate size selection is key to obtaining optimal downstream performance and NGS sequencing results.

Current methods and chemistries for the purposes listed above have been in use for several years; however, they are utilized at the cost of performance and ease-of-use. Many library preparation methods involve serial purifications which can result in a loss of DNA. Current methods can result in as much as 20-30% loss with each purification step. Ultimately this may necessitate greater starting material, which may not be possible with limited, precious samples, or the incorporation of more PCR cycles which can result in sequencing bias. Sample-to-sample reproducibility is a daily challenge that is also regularly cited as an area for improvement in size-selection.

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Methods for Quantitating Your Nucleic Acid Sample

Posted on by Sara Klink
Nucleic acid quanitation webinar

For most molecular biology applications, knowing the amount of nucleic acid present in your purified sample is important. However, one quantitation method might serve better than another, depending on your situation, or you may need to weigh the benefits of a second method to assess the information from the first. Our webinar “To NanoDrop® or Not to NanoDrop®: Choosing the Most Appropriate Method for Nucleic Acid Quantitation” given by Doug Wieczorek, one of our Applications Scientists, discussed three methods for quantitating nucleic acid and outlined their strengths and weaknesses.

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Bisulfite Conversion and Next Gen Sequencing

Posted on by admin

WebinarsIn my last entry, I gave a little summary of one of many techniques that are used to study DNA methylation patterns in a loci-specific fashion using the COBRA technique. This time, we’ll take a look at a high-throughput, genome-wide method for analyzing DNA methylation status using a next generation sequencing approache called bisulfite sequencing, or Bis-Seq. Continue reading “Bisulfite Conversion and Next Gen Sequencing”