P.E.P.P.E.R.

PEPPER is a genome inference module based on recurrent neural networks that enables long-read variant calling and nanopore assembly polishing in the PEPPER-Margin-DeepVariant pipeline. This pipeline enables nanopore-based variant calling with DeepVariant.

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How to cite

Please cite the following manuscript if you are using PEPPER-Margin-DeepVariant:

Nature Methods: Haplotype-aware variant calling with PEPPER-Margin-DeepVariant enables high accuracy in nanopore long-reads.

Authors: Kishwar Shafin, Trevor Pesout, Pi-Chuan Chang, Maria Nattestad, Alexey Kolesnikov, Sidharth Goel,
Gunjan Baid, Mikhail Kolmogorov, Jordan M. Eizenga, Karen H. Miga, Paolo Carnevali, Miten Jain, Andrew Carroll & Benedict Paten.

Free access link to the manuscript: https://rdcu.be/cABfv

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Critical care application

In a project led by Professor Euan Ashley, the team demonstrated the ability to identify clinically actionable disease causing variants in a critical care setting with nanopore sequencing and PEPPER-Margin-DeepVariant.

Following are the publications that demonstrate the performance of PEPPER-Margin-DeepVariant in a clinical setup:

Clinical report:

New England Journal of Medicine: Ultrarapid Nanopore Genome Sequencing in a Critical Care Setting

Authors: John Gorzynski, Sneha Goenka, Kishwar Shafin, Tanner Jensen, Dianna Fisk, Megan Grove, Elizabeth Spiteri, Trevor Pesout, Jean Monlong, Gunjan Baid, Jonathan Bernstein, Scott Ceresnak, Pi-Chuan Chang, Jeffrey Christle, Henry Chubb, Karen Dalton, Kyla Dunn, Daniel Garalde, Joseph Guillory, Joshua Knowles, Alexey Kolesnikov, Michael Ma, Tia Moscarello, Maria Nattestad, Marco Perez, Maura Ruzhnikov, Mehrzad Samadi, Ankit Setia, Chris Wright, Courtney J Wusthoff, Katherine Xiong, Tong Zhu, Miten Jain, Fritz Sedlazeck, Andrew Carroll, Benedict Paten, Euan Ashley.

Case report:

Circulation: Genomic and Precision Medicine:Ultra-Rapid Nanopore Whole Genome Genetic Diagnosis of Dilated Cardiomyopathy in an Adolescent With Cardiogenic Shock

Authors: John Gorzynski, Sneha Goenka, Kishwar Shafin, Tanner Jensen, Dianna Fisk, Megan Grove, Elizabeth Spiteri, Trevor Pesout, Jean Monlong, Jonathan Bernstein, Scott Ceresnak, Pi-Chuan Chang, Jeffrey Christle, Henry Chubb, Kyla Dunn, Daniel Garalde, Joseph Guillory, Maura Ruzhnikov, Chris Wright, Courtney Wusthoff, Katherine Xiong, Seth Hollander, Gerald Berry, Miten Jain, Fritz Sedlazeck, Andrew Carroll, Benedict Paten, Euan Ashley.

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Long read variant calling performance evaluation

Detailed variant calling performance evaluation:

• Nanopore R9.4.1 Guppy 5.0.6 SUP:
  • HG003 whole genome

Please follow the case-studies documentation for PacBio-HiFi and ONT 10.4 Q20 performance evaluation.

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Useful links to documentations

• Quickstarts to check system configuration.
• Case-studies to reproduce performance.
• Description of PEPPER-Margin-DeepVariant method.
• How to train PEPPER-DeepVariant:
  • How to train PEPPER.
  • How to train DeepVariant (using candidates from PEPPER).
• How to install PEPPER locally.
• List of parameters and description.
• How to tune parameters to balance speed and accuracy.

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How to run

PEPPER-Margin-DeepVariant can be run using Docker or Singularity. A simple docker command looks like:

sudo docker run \
-v "${INPUT_DIR}":"${INPUT_DIR}" \
-v "${OUTPUT_DIR}":"${OUTPUT_DIR}" \
kishwars/pepper_deepvariant:r0.8 \
run_pepper_margin_deepvariant call_variant \
-b "${INPUT_DIR}/${BAM}" \
-f "${INPUT_DIR}/${REF}" \
-o "${OUTPUT_DIR}" \
-t "${THREADS}" \
--ont_r9_guppy5_sup

# --ont_r9_guppy5_sup is preset for ONT R9.4.1 Guppy 5 "Sup" basecaller
# for ONT R10.4 Q20 reads: --ont_r10_q20
# for PacBio-HiFi reads: --hifi

Quickstarts (small runs to test system configuration)

Test type	Links
Docker quickstart	Link
Singularity quickstart	Link
Docker-gpu quickstart	Link

Case studies (chromosome 20 runs for performance reproducibility)

Pipeline	Docker	Singularity	NVIDIA-docker (GPU)
Nanopore R9.4.1 variant calling	Link	Link	Link
Nanopore R10.4 Q20 variant calling	Link	Link	Link
PacBio HiFi variant calling	Link	Link	Link

License

PEPPER license, Margin License and DeepVariant License extend to the trained models (PEPPER, Margin and DeepVariant) and container environment (Docker and Singularity).

Acknowledgement

We are thankful to the developers of these packages:

• htslib & samtools
• pytorch
• ONNX
• hdf5 python (h5py)

Authors

PEPPER-Margin-DeepVariant pipeline is developed in a collaboration between UC Santa Cruz genomics institute and the Genomics team in Google Health.

Fun Fact

The name "P.E.P.P.E.R." is inspired from an A.I. created by Tony Stark in the Marvel Comics (Earth-616).

PEPPER is named after Tony Stark's then friend and the CEO of Resilient, Pepper Potts.