Seqanswers Leaderboard Ad

Collapse

Announcement

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

  • Forward adapter at end of forward paired end read?

    So I was given a metatranscriptome prepped with the Nugen Ovation RNAseq kit.

    The metatranscriptome was sequenced on a HiSeq 2000 paired end.

    In the first read a lot of the sequences ~20% have the forward adapter at the end of the read - this is it's sequence:
    GCTACGGGATGACTTGTGATTAGGGGTGAGAATGTCGGCCTGAGAGATCGGAAGAGCGGTTCAGCAGGAATGCCGAGACCGATCTCGTATGCCGTCTTCTGC

    I'm just wondering what could cause this -
    Here's an example read with the adapter in it. If anything shouldn't it be at the front of the read? Why would it be at the end and why is there still more sequence after it?

    GCTACGGGATGACTTGTGATTAGGGGTGAGAATGTCGGCCTGAGAGATCGGAAGAGCGGTTCAGCAGGAATGCCGAGACCGATCTCGTATGCCGTCTTCTGC

    Thanks

  • #2
    Reading into the adapter sequence can happen when the fragment size is less than the read length. This would show up as a partial adapter sequence at the 3' end (right side) of a read, as you have observed. There are quite a few tools out there that will trim the adapter portion of a read (see here for a discussion, and also search for threads here on seqanswers). I'm not sure how well these tools deal with reads that go through the entire adapter sequence and beyond - one possibility might be to pad the 3' end of the adapter sequence with Ns before running one of these tools.

    Comment

    Latest Articles

    Collapse

    • seqadmin
      Essential Discoveries and Tools in Epitranscriptomics
      by seqadmin


      The field of epigenetics has traditionally concentrated more on DNA and how changes like methylation and phosphorylation of histones impact gene expression and regulation. However, our increased understanding of RNA modifications and their importance in cellular processes has led to a rise in epitranscriptomics research. “Epitranscriptomics brings together the concepts of epigenetics and gene expression,” explained Adrien Leger, PhD, Principal Research Scientist on Modified Bases...
      Yesterday, 07:01 AM
    • seqadmin
      Current Approaches to Protein Sequencing
      by seqadmin


      Proteins are often described as the workhorses of the cell, and identifying their sequences is key to understanding their role in biological processes and disease. Currently, the most common technique used to determine protein sequences is mass spectrometry. While still a valuable tool, mass spectrometry faces several limitations and requires a highly experienced scientist familiar with the equipment to operate it. Additionally, other proteomic methods, like affinity assays, are constrained...
      04-04-2024, 04:25 PM

    ad_right_rmr

    Collapse

    News

    Collapse

    Topics Statistics Last Post
    Started by seqadmin, 04-11-2024, 12:08 PM
    0 responses
    39 views
    0 likes
    Last Post seqadmin  
    Started by seqadmin, 04-10-2024, 10:19 PM
    0 responses
    41 views
    0 likes
    Last Post seqadmin  
    Started by seqadmin, 04-10-2024, 09:21 AM
    0 responses
    35 views
    0 likes
    Last Post seqadmin  
    Started by seqadmin, 04-04-2024, 09:00 AM
    0 responses
    55 views
    0 likes
    Last Post seqadmin  
    Working...
    X