Unconfigured Ad

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • lran2008
    Member
    • Apr 2013
    • 35

    #1

    blast result against rfam database

    Hi All,

    I am blasting my miRNA-seq fasta file against rFam data base. Here is the command line I used:
    blastn -query TOTAL_mapped_reads.fa -task megablast -db Rfam.fasta -out mapped_vs_rfam.txt -outfmt "6 qseqid sseqid qlen evalue pident nident mismatch qcovs qcovhsp"

    Then I want to retrive those reads which match tRNAs in rFam.
    There are many hits in the output (see the attached picture).

    But when I pick the first read which is shown to be 100% match with rRNA in rfam by searching it in rfam website, there is no hit.
    >62-796337
    TCCCATATGGTCTAGCGGTTAGGATTCCTGGTT

    Briefly, according to my blast result against rfam database, there is a match, but when I search the my sequence in online rfam website, there is no hit. So what is the problem?
    Attached Files
  • rhinoceros
    Senior Member
    • Apr 2013
    • 372

    #2
    Based on blastn (at ncbi) your sequence is not a tRNA. The 'best' hit is "PREDICTED: Dasypus novemcinctus WW domain-binding protein 4-like (LOC101430251), transcript variant 2, mRNA".

    Perhaps consider a more conservative evalue cutoff? Also, how did you create your Rfam db? "-db Rfam.fasta" looks rather wrong to me but maybe you just named it oddly...
    savetherhino.org

    Comment

    • lran2008
      Member
      • Apr 2013
      • 35

      #3
      Originally posted by rhinoceros View Post
      Based on blastn (at ncbi) your sequence is not a tRNA. The 'best' hit is "PREDICTED: Dasypus novemcinctus WW domain-binding protein 4-like (LOC101430251), transcript variant 2, mRNA".

      Perhaps consider a more conservative evalue cutoff? Also, how did you create your Rfam db? "-db Rfam.fasta" looks rather wrong to me but maybe you just named it oddly...
      I indeed named it oddly. Anyway, it produced results, but seems to be unreliable... The e value for 62-796337 is 1e-10 in the attached picture. So what's your suggestion for the e value cutoff?

      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, 10-22-2026, 11:13 AM
      0 responses
      23 views
      0 reactions
      Last Post SEQadmin2  
      Started by SEQadmin2, 10-22-2026, 10:48 AM
      0 responses
      20 views
      0 reactions
      Last Post SEQadmin2  
      Started by SEQadmin2, 10-15-2026, 10:52 AM
      0 responses
      36 views
      0 reactions
      Last Post SEQadmin2  
      Started by SEQadmin2, 10-14-2026, 05:39 AM
      0 responses
      42 views
      0 reactions
      Last Post SEQadmin2  
      Working...