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  • Extract index reads from raw Fastq file

    We sequenced some 16S rRNA gene amplicons on our collaborator's MiSeq, and got the raw fastq file that looks like the seqs below.
    It seems that there are only reads_1 and reads_2 in the file, and the index reads are missing.
    In addition, the 1:N:0 or 2:N:0 in the header are missing the sample number as seen in the MiSeq fastq files.
    As I need the index reads to feed the data to Qiime for further analysis, I have the following questions:
    1. Is the index-reads info still in this fastq file?
    2. If yes, Is there a way I can extract the index reads?
    3. If no, besides asking our collaborator for the index reads (which I've done but haven't heard from them), is there any other similar program as Qiime but does not require an index read file as the input?
    Thank you for any feedback.
    @MISEQ04:37:000000000-A2G8E:1:1101:14157:1957 1:N:0:TCCACAGGAGT
    TACAGAGGGTGCAAGCGTTAATCGGAATTACTGGGCGTAAAGCGCGCGTAGGTGGTTTGTTAAGTTGGATGTGAAATCCCCGGGCTCAACCTGGGAACTGCATTCAAAACTGACTGACTAGAGTATGGTAGAGGGTGGTGGAATTTCCTGTGTAGCGGTGAAATGCGTAGATATAGGAAGGAACACCAGTGGCGAAGGCGACCACCTGGACTGATACTGACACTGAGGTGCGAAAGCGTGGGGAGCAAACA
    +
    ?????BB?DDDDDEDDEEEEFFHIHECFFHHHIIIFHHHHIIIEHHHHEHHHAEFEHHEHHEGHHHHHHHHHHHFFFHHHHHHFFEFEFFFFFFFEEEFFFFFFFFFEFFFFFFFFEFFEFFEEFFFFFFFEEFEEFDEEEEEFFFFFFECEEEFEDDED?AACEEEEEDAEEEFEFEFEEEEEEEEEFECEE>?>?8A>;???EEFEEEFFCEE?*1::A:A0CCECA*14)48AEEEE>;;8;88:AC#
    @MISEQ04:37:000000000-A2G8E:1:1101:14157:1957 2:N:0:TCCACAGGAGT
    ACGGACTACCCGGGTTTCTAATCCTGTTTGCTCCCCACGCTTTCGCACCTCAGTGTCAGTATCAGTCCAGGTGGTCGCCTTCGCCACTGGTGTTCCTTCCTATATCTACGCATTTCACCGCTACACAGGAAATTCCACCACCCTCTACCATACTCTAGTCAGTCAGTTTTGAATGCAGTTCCCAGGTTGAGCCCGGGGATTTCACATCCAACTTAACAAACCACCAACCCGCGCTTTACGCCCAGCAATTC
    +
    ?????@@BDDDDDDDDEFFFFFCFFHHHHHHGFHHHHHCDDHHDEDEHHHHHHHFEHFHGGGHHHHHHFCFHHHHF=EEEDCDEHEHHFCFHHEFHFHHFFFFFFFFFFFEEDEEDDDDEE<6@EBCEEFFFFECEEEEECEEE8:CEFFAECECEFAEFE?CEEEECAAAEAEEEFFCEFFFFEE?CEEAEFE'.8?88:?*:AE:CE?*1*:?C*?A?EAEE###########################
    @MISEQ04:37:000000000-A2G8E:1:1101:14713:1991 1:N:0:TCCACAGGAGT
    AACGGAGGGGGCAAGTGTTTCTCGCAATGACTGGGCCTAAAGGGCACGCAGGTGGTTTTCGACAACAGGTATTTCGGTTAAACACTGCAGGCTAACAACAGGTCTGGAATATCTACTAGGAAACTAAGAGTAGTGCTCAGGTCTTTAGAATTGCTAGCGGAGGGGTGGAATCCGGCGAGGCTAGTAGGAATGCTTATGAGTGAAGGCAATTTTCTGGAGCTGACTGACGCTCAGGTGCGCAAGCATGGGGA
    +
    9?????@@DDDDDDDDFFFFFFIEHHHHHHHIIHHIIHHHIHHHIHHEHHHHAEFEHIIIHHHH=FHHHC=DFHFFHEHHFFFFFFFFFDEEEFFFFFFFFFBEEFE=BEEEFFFFEEEEAECEFFFFFFCCEEFFFF?AECAEFFEEEEFFFFFEEEDD8<>DD)8>AEECEA?D?D?D>C?C??:E1?CEEAE?:CAECEAEFFFE8AEEF:?:A:8?*?*:?CAEEEEADCC*0??DD8<?ECEEEE#
    @MISEQ04:37:000000000-A2G8E:1:1101:14713:1991 2:N:0:TCCACAGGAGT
    ACGGACTACTGGGGTATCTAATCCTATTTGATCCCCATGCTTGCGCACCTGAGCGTCAGTCAGCTCCAGAAAATTGCCTTCACTCATAAGCATTCCTACTAGCCTCGCCGGATTCCACCCCTCCGCTAGCAATTCTAAAGACCTGAGCACTACTCTTAGTTTCCTAGTAGATATTCCAGACCTGTTGTTAGCCTGCAGTGTTTAACCGAAATACCTGTTGTCGCAAACCACCTGCGTGCCCTTTAGGCCCA
    +
    AAA?AABBDDDDDD<AFFFGFGHIHFFHHIIHHHHIHIIIIIHHHH@HHIIFHHHHHHHIIHHIIHHGHHFHIIIHHHFCECGHHFHIIHHHHHHHHHHHHHFHDHHHHGGGGGDEEGDEGCGGEEGGGGGGEEGGGEGEEEGCGGCGCEGGGGGGGGGEGGGGEGGEGG?CGGGGGEGGGGGGGGCGEGGCEEGGGGEECEG?C:?828<CCE?EGGGCCCC*.).CC?CEECE8CEC*11CEEE#####
    @MISEQ04:37:000000000-A2G8E:1:1101:13997:2108 1:N:0:TCCACAGGAGT
    TACGTAGGGTGCGAGCGTTAATCGGAATTACTGGGCGTAAAGCGTGCGCAGGCGGTTAATTAAACCAGTTGTGAAATCCCCGGGGTCAACCTGGGAATTGCATCTGTGACTGTATAGCTAGAGTACGGTAGAGGGGGATGGGATTCAGCGGGTAGCCGGGAAAAGCGTAGATATGCCGAGGAAACACGGAGGCGAAGGGAATTCTCTGGAACTGGACTTGCGCTCCTGCACGAAAAGCTGGGGAGGAAACA
    +
    ?????BB?BDDDBBBDDDEEFFHIHHHHHHHIHHHIHHHHIHHHEHECEHECEHH<<<,,,,5,,44+4C,@D,CF,,@FF);@))34AAC################################################################################################################################################################
    @MISEQ04:37:000000000-A2G8E:1:1101:13997:2108 2:N:0:TCCACAGGAGT
    ACGGACTACAAGGGTTTCTAATCCTGTTTGCTCCCCACGCTTTCGTGCATGAGCGTCAGTACAGGTCCAGAGGATTGCCTTCGCCATCGGTGTTCCTCCGCATATCTACGCATTTCACTGCTACACGCGGAATTCCATCCCCCTCTACCGTACTCTAGCTATACAGTCACAGATGCAATTCCCAGGTTGAGCCCGGGGATTTCACAACTGTCTTATATAACCGCCTGCGCACGCTTTACGCCCAGCAATTC
    +
    ?????@@BDDDBDD?BEFFFFFFHIIHHHHHIIHHHIC=DDFFGHHFHHIIIHFCCEEHGHIHHH-AEFHDDFFHHHFGGFFHHHHHFHECDEEDHHDFCDEDDFFDFFF@DDED=DEED=,ACFFAEDEDDAEFFFFE?C??8EEEF:8).:AAAEF?CEAECEA?:::CC:?EEEFFE?CCECE*?*:?ADDD84)*1:?EEEECA*00::*::CE:?>'.A?EDD;''')08*AEAD48?######

  • #2
    BTW, another question:
    1. Do the sequences look like they've already been de-multiplexed?
    Also, I am suspecting the index reads are missing b/c I only saw long reads like the ones shown above, but not the shorter ones seen elsewhere.

    Comment


    • #3
      The reads are already de-multiplexed. The tag for the particular sample is appended to the end of the ID line (example below from your data)

      @MISEQ04:37:000000000-A2G8E:1:1101:13997:2108 2:N:0:TCCACAGGAGT

      The two reads (pairs R1--> <--R2) also appear to have been already interlaced.
      Last edited by GenoMax; 02-13-2013, 11:32 AM.

      Comment


      • #4
        I assume you have multiple sample files? Each file should have the sample_ID (somewhere in the file name).

        Comment


        • #5
          Originally posted by GenoMax View Post
          I assume you have multiple sample files? Each file should have the sample_ID (somewhere in the file name).
          Thanks GenoMax. For this raw Fastq file I got the sequences from, it is a pooled sample of multiple indexed-samples.

          Comment


          • #6
            Originally posted by ostrakon View Post
            Thanks GenoMax. For this raw Fastq file I got the sequences from, it is a pooled sample of multiple indexed-samples.
            So hopefully you have the mapping of "tags" <--> "sample_ID" and can split the original file, if needed.

            Comment


            • #7
              Originally posted by GenoMax View Post
              So hopefully you have the mapping of "tags" <--> "sample_ID" and can split the original file, if needed.
              Thank you again, GenoMax. I have the mapping info. I am very glad that the Qiime guys have resolved this issue. They made a python script to parse the raw fastq files, extract the index, and add fake quality scores to make an index read file. I am now happily splitting libraries using the mapping info and the index read file generated this way.

              Here is the reference in case anyone has a similar fastq file as mine:

              https://groups.google.com/forum/?fromgroups=#!topicsearchin/qiime-forum/mariana$20illumina$20sequencing/qiime-forum/TJOtt13jlPs

              Comment

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