# Where to find the reference sequence used for phiX alignment?

The reference sequence used for PhiX alignment can be found in the [Illumina iGenomes page](https://support.illumina.com/sequencing/sequencing_software/igenome.html).

All Illumina sequencing instruments already have the phiX reference, so the above reference is not required for assessing phiX alignment rates in sequencing runs. The sequence is made available as a reference, if needed.

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