Unconfigured Ad

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Alun3.1
    Junior Member
    • Feb 2015
    • 8

    #1

    Program for aligning particular set of reads to an entire NGS dataset

    Hi,

    I have about 100 cDNA sequences (let's call them "ref.") for which I would like to know how many reads from the original Illumina dataset (10 millions of reads; let's call them "reads") align to them fully (i.e. the entire ref. sequence is in the read; see "read1" below) or partially (see "reads 2, 3, 4" below) without gaps.

    Example:
    Code:
    [COLOR="red"]ref.                   AGTTCGGCCGCTCACCGCACCGTCACGCCATCCAGGCATC[/COLOR]
    read1  ATGCGCTAGCTAGCATAGTTCGGCCGCTCACCGCACCGTCACGCCATCCAGGCATCTTGGACCGCATAGCATC
    read2              ATTAAGTTCGGCCGCTCACCGCACC
    read3                                CCGCACCGTCACGCCATCCAGGCATCATGCGCGATCTCAGC
    read4                        GCCGCTCACCGCACC
    Is there any "mapping" program to do that?

    Can I use Bowtie2 (although it seems a bit complicated to use when I look at the extensive list of the option arguments)? It seems like I would have to input one file containing all the sequences (ref. + reads), which would probably align all the sequences to each other and take ages?
    Also should I used the raw reads (paired-end) or the merged+unmerged reads?

    Thanks for your help !
  • westerman
    Rick Westerman
    • Jun 2008
    • 1104

    #2
    bowtie2 is good. Yes there are lot of arguments but that is because different people want to do different things. For example in your case you will want to use the non-default '--local' mapping.

    You will not input just one file. Instead you will create an index file for your reference(s) and then input the R1 and R2 read files separately.

    Comment

    • Alun3.1
      Junior Member
      • Feb 2015
      • 8

      #3
      Got it. Thanks westerman !

      Comment

      • archana2287
        Junior Member
        • Feb 2015
        • 5

        #4
        i did mapping using tophat, where length of reference was minimum 150 bp and max 50,000bp (worked on approx 40,000 reference sequence separately). I mapped paired end reads collectively rather than separate. Both mapping could end up with slight or major difference in mapping (It should be bothered for short stretch reference where reference length is less than 300 bp (just hypothetical statement) . Doing mapping of paired end R1 and R2 seperately, will be followed by selecting those reads that mapped in both mapping ?? right ?? Now how we will encounter the insert size parameter ?? and how i can perform the local mapping in tophat ?? is there any way to do so ??

        Comment

        • Brian Bushnell
          Super Moderator
          • Jan 2014
          • 2709

          #5
          Originally posted by archana2287 View Post
          i did mapping using tophat, where length of reference was minimum 150 bp and max 50,000bp (worked on approx 40,000 reference sequence separately). I mapped paired end reads collectively rather than separate. Both mapping could end up with slight or major difference in mapping (It should be bothered for short stretch reference where reference length is less than 300 bp (just hypothetical statement) . Doing mapping of paired end R1 and R2 seperately, will be followed by selecting those reads that mapped in both mapping ?? right ?? Now how we will encounter the insert size parameter ?? and how i can perform the local mapping in tophat ?? is there any way to do so ??
          This appears to have limited relevance to this thread, so I suggest you create a new thread to ask the question. And please take your time to phrase it clearly.

          Comment

          Latest Articles

          Collapse

          • SEQadmin2
            Multiomic Liquid Biopsy: What DNA/RNA Panels Reveal That DNA Alone Can’t
            by SEQadmin2



            Tumors contain complex mixtures of cell populations that evolve in response to treatment and host-specific factors. Tissue biopsies provide only static snapshots of a tumor’s state. But what if we could follow that evolution over time using a minimally invasive technique?

            Liquid biopsies can detect tumor-derived material circulating in the bloodstream, providing a way to study treatment response, detect emerging resistance, and discover new biomarkers. Circulating
            ...
            10-14-2026, 09:55 AM
          • SEQadmin2
            New Genomics Technologies Take Aim at Long-Standing Limits
            by SEQadmin2


            Researchers using sequencing and genomics tools often have to make trade-offs. They can choose between speed or scale, short reads or long-range information, or targeted panels or a view of the whole transcriptome. New technologies that have been released this year are built to address those tough choices.

            We asked six companies the same four questions to learn about their latest products. The new technologies bring a lot to the table, including rethinking sequencing
            ...
            09-28-2026, 10:25 AM

          ad_right_rmr

          Collapse

          News

          Collapse

          Topics Statistics Last Post
          Started by SEQadmin2, Yesterday, 10:52 AM
          0 responses
          12 views
          0 reactions
          Last Post SEQadmin2  
          Started by SEQadmin2, 10-14-2026, 05:39 AM
          0 responses
          19 views
          0 reactions
          Last Post SEQadmin2  
          Started by SEQadmin2, 10-13-2026, 09:56 AM
          0 responses
          19 views
          0 reactions
          Last Post SEQadmin2  
          Started by SEQadmin2, 10-09-2026, 11:14 AM
          0 responses
          27 views
          0 reactions
          Last Post SEQadmin2  
          Working...