General comparison between QS When switching from QuantSeq-FWD to QuantSeq-Pool, there are certain considerations researchers should take to ensure QuantSeq-Pool is the appropriate kit for their application.
General comparison between QuantSeq-FWD (Cat. No. 191-196) and
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QuantSeq-Pool (Cat. No. 139)
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QuantSeq-FWD | QuantSeq-Pool | |
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Input |
amounts | 1ng - 500ng |
I prefer not to mention any input lower than 1 ng.
I would rather indicate:
1 ng - 500 ng
* *low input protocol |
modifications available for 1 ng - 10 ng. | 10ng - 120ng per sample |
into First Strand Synthesis. 80ng - 960ng per pool |
into Second Strand Synthesis. |
RNA quality |
High and low quality RNA is acceptable, as well as FFPE RNA. | Medium |
to high quality RNA required (i.e., RIN >6). | |
Blood samples | Compatible with |
cat n°
Block Modules |
cat n°
and 071 (Sus scrofa)). | Not recommended |
UMI
UMI
. | |
Unique Molecular Identifiers (UMIs) | Optional with UMI Second Strand Synthesis Module (Cat. No. 081). |
plus a 4 |
nt spacer) and added during |
Second Strand Synthesis. | Included. |
Added during first strand synthesis
and added during First Strand Synthesis. | ||
First Strand Synthesis Primer | Oligo(dT) primer with partial Illumina adapter sequence. | Oligo(dT) primer with |
12 nt i1 barcode, |
10 nt UMI, and partial Illumina adapter sequence. | ||
Library Quality Control (QC) | QC individual libraries and pool at equimolar ratio. | QC final, pooled library; individual library QC not possible due to early pooling after reverse transcription. |
Average Library Size | ~335 – 456 bp (based on UHRR)* *Can vary based on RNA quality and sample type. | ~650 bp (based on UHRR)* *Can vary based on RNA quality and sample type. |
Sequencing mode | Single Read (SR) Read 1: insert; 50 – 150bp | Paired End Read (PE) |
Demultiplexing | i5/i7 demultiplexing required |
I would like to promote idemux here
. |
|
iDemux for demultiplexing and optimal error correction. | i5/i7 demultiplexing optional (if UDI are used). i1 demultiplexing required ( |
iDemux recommended) |
. If only using Lexogen 12 nt UDI in your sequencing lane (e.g., with other Lexogen libraries), we recommend |
iDemux for demultiplexing and optimal error correction. |
What components are interchangeable
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between QuantSeq-FWD and QuantSeq-Pool?
FS in |
QuantSeq-Pool and FS1/FS2 in |
QuantSeq-FWD | Not interchangeable |
First Strand Synthesis Enzyme (E1) | Interchangeable |
Purification |
Module (PB, PS, EB) | Interchangeable |
RPM in |
QuantSeq-Pool and SS1/SS2 in |
QuantSeq-FWD | Not interchangeable |
Second Strand Synthesis Enzyme (E2) | Not interchangeable |
Library Amplification Module | PM and PE are interchangeable NOTE: P5 and P7 required for |
QuantSeq-Pool when no i5/i7 indexing is done. |
Note |
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When switching from QuantSeq-FWD to QuantSeq-Pool, we strongly encourage you to perform a pilot experiment, to ensure you are satisfied with the data. If performing a head-to-head comparison of QuantSeq-FWD and QuantSeq-Pool, consider the experimental set-upfollowing: |
Use same input amountCompare samples at same read depth - down sample the same sample type and same input amounts.
Include technical replicates to assess handling variability (QuantSeq-FWD samples are processed separately whereas QuantSeq-Pool samples are processed together).
Optional: Include spike-in RNA controls (SIRVs) for assessing differential gene expression to determine “ground truth” (comparing expected vs observed).
Compare samples using the same read depth and downsample if necessary (e.g., if you have 10 million reads in library for Sample A and 1 million reads in library for Sample B, you need to randomly - through bioinformatics - decrease the number of analysed reads in library A down to 1 million)Same randomly discard a specified fraction of reads so Sample A and Sample B both have 1 million reads.). If you have questions about downsampling, please contact support@lexogen.com.
Use the same Read 1 length (i.e., insert length). We recommend >75bp for Read 1.
Do not collapse UMIs, even if UMIs are included in QuantSeq-FWD (with SSS UMI Module)
Include
Recommend includingtechnical replicates to assess handling variability (QSF samples processed separately whereas QSP samples processed together)Include
Recommend includingcontrols (SIRVs) as “ground truth” (compare expected vs observed) to assess differential gene expressionDEG, if interested in this parameter(compare expected vs observed)
What can also cause differences:
Differences in chemistries and protocol. It is instead advised to check the correlation of non-collapsed samples.