Custom primers on the MiniSeq

Using Custom Primers on the MiniSeq System

When using custom primers with the MiniSeq, it is important to follow specific setup procedures to ensure successful sequencing. This article outlines how to specify and load custom primers, primer position assignments, and key contingencies related to the dual-indexed workflow.

Specifying Custom Primers

Custom primers must be designated during run setup:

    • Via MiniSeq Control Software: During run setup, if using the dedicated custom primer wells.

    • Via Local Run Manager (LRM): On the Create Run screen, select the checkboxes for each custom primer being used (Read 1, Index 1, Index 2, Read 2). This ensures the system recognizes and uses the correct wells for custom primers.

The system uses the Primers.xml file to record which primer positions were used. This file is located in the Reagents folder of the run directory.

Primer Position Assignments

Primer Type

Position

Description

Custom Primers

15

Custom Read 1 Primer

14

Custom Read 2 Primer

13

Custom Index 1 and Index 2 Primers

Illumina Primers

24

Illumina Read 1 Primer

25

Illumina Read 2 Primer

28

Illumina Index 1 and Index 2 Primer Mix

  • Note: If Illumina primers are not used for Read 1 or Read 2, the optional Illumina PhiX control library will not be sequenced.

Primer Contingencies & Compatibility

Due to the dual-indexed sequencing workflow on the MiniSeq, users must load complementary primers when using custom primers for any read. This ensures proper sequencing chemistry and data quality.

    • If using a custom Read 1 primer, you must also load the reverse complement of the Index 2 primer.

    • If using a custom Read 2 primer, you must also load the reverse complement of the Index 1 primer.

In most cases, failure to load the appropriate complementary primer will result in sequencing failure or incomplete data.

MiniSeq Standard Reagent Kits

Combination

Read 1 Primer

Index 1 Primer

Index 2 Primer

Read 2 Primer

All Illumina

Illumina Read 1

Illumina Index 1

Illumina Index 2

Illumina Read 2

Custom Read 1

Custom Read 1

Custom Index 1

Custom Index 2

Illumina Read 2

Custom Read 2

Illumina Read 1

Custom Index 1

Custom Index 1

Custom Read 2

All Custom

Custom

Custom

Custom

Custom

See the MiniSeq System Custom Primer Guide for MiniSeq Rapid Reagent Kit Compatible Primer Combinations.

Primer Preparation and Loading

Dilution: Use HT1 buffer to dilute primers to 0.3 µM in 2 ml total volume.

Loading:

    • Load 1 ml of each primer into the designated well.

    • If using custom primers for both index reads, load 0.5 ml of each into position 13.

Custom Primer Loading Volumes by Position

Position

Volume

Primer Description

15

1 ml

Custom Read 1 Primer

14

1 ml

Custom Read 2 Primer

13

1 ml

Custom Index 1 Primer

13

0.5 ml each

Custom Index 1 Primer and Custom Index 2 Primer

13

1 ml

Custom Index 2 Primer

For more information, see MiniSeq System Custom Primer Guide.

For any feedback or questions regarding this article (Illumina Knowledge Article #2029), contact Illumina Technical Support [email protected].

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