Seqanswers Leaderboard Ad

Collapse

Announcement

Collapse
No announcement yet.
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Looking for mapper that produces padded alignments

    Hi everyone,
    I'm looking for an RNAseq mapping tool (not a de novo assembler!) that is able to output padded alignments ('P' char in the cigar string) against a reference. I would be grateful for any suggestions!
    W
    Last edited by WhatsOEver; 07-22-2014, 06:40 AM. Reason: solved

  • #2
    I'd be a bit surprised if one exists. There's no reason to create one to produce padded alignments since padding has no biological meaning. Further, the padding can only be calculated after the mapping is complete, since it's for viewing multiple alignments.

    Comment


    • #3
      I know all this... still, I need this kind of alignment. It's just a question whether something like this already exists or I have to write it on my own.

      Comment


      • #4
        Maybe it's better to give the example from the sam spec to show what I mean:

        Code:
        Padded alignment.
        
        Most sequence aligners only give the sequences inserted to the reference genome, 
        but do not present how these inserted sequences are aligned against each other. 
        Alignment with inserted sequences fully aligned is
        called padded alignment. Padded alignment is always produced by
        de novo assemblers and is important for an alignment viewer to display the 
        alignment properly. To store padded alignment, we introduce operation ʻPʼ which 
        can be considered as a silent deletion from padded reference sequence. In the 
        following example, GA on READ1 and A on READ2 are inserted to the reference. 
        With unpadded CIGAR, we would not be able to distinguish the following padded 
        multi-alignments:
        
        [FONT="Courier New"]REF: CACGATCA**GACCGATACGTCCGA           REF: CACGATCA**GACCGATACGTCCGA
        READ1: CGATCAGAGACCGATA                  READ1: CGATCAGAGACCGATA
        READ2:   ATCA*AGACCGATAC                 READ2:   ATCAA*GACCGATAC
        READ3:  GATCA**GACCG                     READ3:  GATCA**GACCG
        
        The padded CIGAR are different:
        READ1: 6M2I8M                            READ1: 6M2I8M
        READ2: 4M1P1I9M                          READ2: 4M1I1P9M
        READ3: 5M2P5M                            READ3: 5M2P5M[/FONT]
        I need to work with the left one, not the right one. Are there any tools/libraries/whatever available to do it?

        Comment


        • #5
          I'm not aware of a tool to do this... You might have to write a bit of code to post-process your traditional alignment output?
          Last edited by maubp; 07-22-2014, 04:22 AM. Reason: Typo

          Comment


          • #6
            I actually thought there should be something, as these kind of alignments are used in alignment viewers, aren't they?
            But there was indeed nothing I could use - I have now written my own code, yes.
            I would have closed the thread (or add a "solved" to the title or deleted everything), but that's not possible here, is it?

            Comment


            • #7
              A few alignment views like 'samtools tview' and bambino can expand inserts, but most SAM/BAM viewers do not show the insert explicitly and ignore CIGAR P operators.

              You can edit the title via editing the original post, but this isn't really solved, is it?

              Comment


              • #8
                Originally posted by maubp View Post
                A few alignment views like 'samtools tview' and bambino can expand inserts, but most SAM/BAM viewers do not show the insert explicitly and ignore CIGAR P operators.
                I looked at bambino and tablet. Both are able to produce padded alignments. But you cannot export them (as no one seems to be interested in it).


                You can edit the title via editing the original post
                I always use quick editing were you can't edit the title. Have found it under advanced, thanks.

                but this isn't really solved, is it?
                Well, I couldn't find a tool, nobody could suggest one, I wrote one on my own which works nicely; so, now there is one, which I have. I consider this as solved

                Comment


                • #9
                  It's not solved till you make the tool it publicly available

                  Comment


                  • #10
                    I'm a little late to this discussion since you've written what you need already. But since your solution isn't publicly available yet I'll point out that Geneious (which is commercial software) has an iterative mapper which produces padded alignments. There is a short video demonstrating this at https://www.youtube.com/watch?v=IOGmxjK3f_4

                    Comment


                    • #11
                      @Brian: Good point, but so far its highly tailored to my specific needs. Once it is in a state were someone else can use it, I can make it public.

                      @Matt: Thanks for the info. I should have mentioned that it is (so far) not important enough to pay for it. I'm actually just testing if this is an improvement to my current project.

                      Comment

                      Latest Articles

                      Collapse

                      • seqadmin
                        Strategies for Sequencing Challenging Samples
                        by seqadmin


                        Despite advancements in sequencing platforms and related sample preparation technologies, certain sample types continue to present significant challenges that can compromise sequencing results. Pedro Echave, Senior Manager of the Global Business Segment at Revvity, explained that the success of a sequencing experiment ultimately depends on the amount and integrity of the nucleic acid template (RNA or DNA) obtained from a sample. “The better the quality of the nucleic acid isolated...
                        03-22-2024, 06:39 AM
                      • seqadmin
                        Techniques and Challenges in Conservation Genomics
                        by seqadmin



                        The field of conservation genomics centers on applying genomics technologies in support of conservation efforts and the preservation of biodiversity. This article features interviews with two researchers who showcase their innovative work and highlight the current state and future of conservation genomics.

                        Avian Conservation
                        Matthew DeSaix, a recent doctoral graduate from Kristen Ruegg’s lab at The University of Colorado, shared that most of his research...
                        03-08-2024, 10:41 AM

                      ad_right_rmr

                      Collapse

                      News

                      Collapse

                      Topics Statistics Last Post
                      Started by seqadmin, 03-27-2024, 06:37 PM
                      0 responses
                      12 views
                      0 likes
                      Last Post seqadmin  
                      Started by seqadmin, 03-27-2024, 06:07 PM
                      0 responses
                      11 views
                      0 likes
                      Last Post seqadmin  
                      Started by seqadmin, 03-22-2024, 10:03 AM
                      0 responses
                      53 views
                      0 likes
                      Last Post seqadmin  
                      Started by seqadmin, 03-21-2024, 07:32 AM
                      0 responses
                      68 views
                      0 likes
                      Last Post seqadmin  
                      Working...
                      X