This protocol describes how to carry out native barcoding of genomic DNA (gDNA) using the Native Barcoding Kit 96 V14 (SQK-NBD114.96). There are 96 unique barcodes available, allowing the user to pool up to 96 different samples in one sequencing experiment. It is highly recommended that a Lambda control experiment is completed first to become familiar with the technology.

Steps in the sequencing workflow:

Prepare for your experiment

You will need to:

• Extract your DNA, and check its length, quantity and purity. The quality checks performed during the protocol are essential in ensuring experimental success.
• Ensure you have your sequencing kit, the correct equipment and third-party reagents
• Download the software for acquiring and analysing your data
• Check your flow cell to ensure it has enough pores for a good sequencing run

Prepare your library

You will need to:

• Repair the gDNA, and prepare the DNA ends for adapter attachment
• Ligate Native barcodes supplied in the kit to the DNA ends
• Ligate sequencing adapters supplied in the kit to the DNA ends
• Prime the flow cell, and load your DNA library into the flow cell

Sequencing

You will need to:

• Start a sequencing run using the MinKNOW software, which will collect raw data from the device and convert it into basecalled reads
• Demultiplex barcoded reads in MinKNOW or the Guppy basecalling, choosing the SQK-NBD114.96 kit option
• Start the EPI2ME software and select a workflow for further analysis (this step is optional)

How to QC your input DNA

It is important that the input DNA meets the quantity and quality requirements. Using too little or too much DNA, or DNA of poor quality (e.g. highly fragmented or containing RNA or chemical contaminants) can affect your library preparation.

For instructions on how to perform quality control of your DNA sample, please read the Input DNA/RNA QC protocol.

Chemical contaminants

Depending on how the DNA is extracted from the raw sample, certain chemical contaminants may remain in the purified DNA, which can affect library preparation efficiency and sequencing quality. Read more about contaminants on the Contaminants page of the Community.

We have validated and recommend the use of all the third-party reagents used in this protocol. Alternatives have not been tested by Oxford Nanopore Technologies.

For all third-party reagents, we recommend following the manufacturer's instructions to prepare the reagents for use.

Note: We are in the process of updating our kits with reduced EDTA concentration.

Higher EDTA concentration format:

† Higher concentration of EDTA with a clear cap.

Reduced EDTA concentration format:

‡ Reduced concentration of EDTA with a blue cap.

Note: This Product Contains AMPure XP Reagent Manufactured by Beckman Coulter, Inc. and can be stored at -20°C with the kit without detriment to reagent stability.

The barcodes are orientated in columns in the barcode plate.

Note: The DNA Control Sample (DCS) is a 3.6 kb standard amplicon mapping the 3' end of the Lambda genome.

These expansions provide extra library preparation and flow cell priming reagents to allow users to utilise any unused barcodes for those running in smaller subsets.

Both expansion packs used together will provide enough reagents for 12 reactions. For customers requiring extra EDTA to maximise the use of barcodes, we recommend using 0.25 M EDTA and adding 4 µl for library preps using the SQK-NBD114.24 kit and 2 µl for preps using the SQK-NBD114.96 kit.

Native Barcode Auxiliary V14 (EXP-NBA114) contents:

Note: This Product contains AMPure XP Reagent manufactured by Beckman Coulter, Inc. and can be stored at -20°C with the kit without detriment to reagent stability.

Sequencing Auxiliary Vials V14 (EXP-AUX003) contents:

The MinION Mk1C contains fully-integrated compute and screen, removing the need for any accessories to generate and analyse nanopore data. Read more in the MinION Mk1C IT requirements document.

Sequencing on a MinION Mk1B requires a high-spec computer or laptop to keep up with the rate of data acquisition. Read more in the MinION Mk1B IT Requirements document.

MinKNOW

The MinKNOW software controls the nanopore sequencing device, collects sequencing data and basecalls in real time. You will be using MinKNOW for every sequencing experiment to sequence, basecall and demultiplex if your samples were barcoded.

For instructions on how to run the MinKNOW software, please refer to the MinKNOW protocol.

EPI2ME (optional)

The EPI2ME cloud-based platform performs further analysis of basecalled data, for example alignment to the Lambda genome, barcoding, or taxonomic classification. You will use the EPI2ME platform only if you would like further analysis of your data post-basecalling.

For instructions on how to create an EPI2ME account and install the EPI2ME Desktop Agent, please refer to the EPI2ME Platform protocol.

We highly recommend that you check the number of pores in your flow cell prior to starting a sequencing experiment. This should be done within three months of purchasing for MinION/GridION/PromethION or within four weeks of purchasing Flongle Flow Cells. Oxford Nanopore Technologies will replace any flow cell with fewer than the number of pores in the table below, when the result is reported within two days of performing the flow cell check, and when the storage recommendations have been followed. To do the flow cell check, please follow the instructions in the Flow Cell Check document.

For most sequencing experiments, use the Library Beads (LIB) for loading your library onto the flow cell. However, for viscous libraries it may be difficult to load with the beads and may be appropriate to load using the Library Solution (LIS).

Once you have loaded your flow cell, the sequencing run can be started on MinKNOW, our sequencing software that controls the device, data acquisition and real-time basecalling. For more detailed information on setting up and using MinKNOW, please see the MinKNOW protocol.

MinKNOW can be used and set up to sequence in multiple ways:

• On a computer either directly or remotely connected to a sequencing device.
• Directly on a GridION, MinION Mk1C or PromethION 24/48 sequencing device.

For more information on using MinKNOW on a sequencing device, please see the device user manuals:

• MinION Mk1B user manual
• MinION Mk1C user manual
• GridION user manual

To start a sequencing run on MinKNOW:

1. Navigate to the start page and click Start sequencing.

2. Fill in your experiment details, such as name and flow cell position and sample ID.

3. Select the sequencing kit used in the library preparation on the Kit page.

4. Configure the sequencing and output parameters for your sequencing run or keep to the default settings on the Run configuration tab.

Note: If basecalling was turned off when a sequencing run was set up, basecalling can be performed post-run on MinKNOW. For more information, please see the MinKNOW protocol.

5. Click Start on the Review page to start the sequencing run.

Kit 14 chemistry has improved duplex basecalling which requires rebasecalling on Dorado after simplex basecalling has been performed on MinKNOW.

For detailed information on setting up your sequencing run, for both simplex and duplex basecalling, please see the Kit 14 sequencing and duplex basecalling info sheet.

Note: When running Dorado, we recommend stopping other basecalling for the best performance by maximising memory available to Dorado. This can be stopped and restarted when Dorado has finished via the GUI on MinKNOW.

After sequencing has completed on MinKNOW, the flow cell can be reused or returned, as outlined in the Flow cell reuse and returns section.

After sequencing and basecalling, the data can be analysed. For further information about options for basecalling and post-basecalling analysis, please refer to the Data Analysis document.

In the Downstream analysis section, we outline further options for analysing your data.

There are several options for further analysing your basecalled data:

1. EPI2ME workflows

For in-depth data analysis, Oxford Nanopore Technologies offers a range of bioinformatics tutorials and workflows available in EPI2ME, which are available in the EPI2ME section of the Community. The platform provides a vehicle where workflows deposited in GitHub by our Research and Applications teams can be showcased with descriptive texts, functional bioinformatics code and example data.

2. Research analysis tools

Oxford Nanopore Technologies' Research division has created a number of analysis tools, that are available in the Oxford Nanopore GitHub repository. The tools are aimed at advanced users, and contain instructions for how to install and run the software. They are provided as-is, with minimal support.

3. Community-developed analysis tools

If a data analysis method for your research question is not provided in any of the resources above, please refer to the Bioinformatics section of the Resource centre. Numerous members of the Nanopore Community have developed their own tools and pipelines for analysing nanopore sequencing data, most of which are available on GitHub. Please be aware that these tools are not supported by Oxford Nanopore Technologies, and are not guaranteed to be compatible with the latest chemistry/software configuration.

We also have an FAQ section available on the Nanopore Community Support section.

If you have tried our suggested solutions and the issue still persists, please contact Technical Support via email (support@nanoporetech.com) or via LiveChat in the Nanopore Community.

We also have an FAQ section available on the Nanopore Community Support section.

If you have tried our suggested solutions and the issue still persists, please contact Technical Support via email (support@nanoporetech.com) or via LiveChat in the Nanopore Community.