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Mark Timko

How to demultiplex a mix of single-indexed and dual-indexed samples

Angel Vasquez  Follow

I'm late to the party but simply run cellranger mkfastq twice, with different arguments for the mask and with --filter-dual-index for the double-indexed samples. In a second step you then have to disentangle the dual A+B reads from single-index A reads based on the readID's that are found in both of the demultiplexings. This is cumbersome and time+diskspace consuming, but it can be done. I would use some Unix tools for that but there are probably smarter ways.

EDIT: I mistakenly said bcl2fastq, this must be cellranger mkfastq. (thanks AmadeusDrZaius)

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Harrie Bours  Follow
Thanks for your suggestion. I only see that "--filter-dual-index" option available for More
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Huang Lu  Follow
, rather than bcl2fastq itself. Is that where you saw the option?More
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Jeremy Kennedy  Follow
cellranger mkfastqMore
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Eric Barnes  Follow
ah yes, that is true, sorry. I guess you would have to do an additional filtering step on the FASTQ file, the second word on the ID lines is 'index1+index2' for properly demultiplexed reads.More
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