Seqanswers Leaderboard Ad

Collapse

Announcement

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

  • Too much "no feature" counts??

    Hello,
    I’m having some issues analysing RNASeq data on Chipster. I have single-end rna samples (brain) sequenced on a illumina NextSeq platform from rattus norvergicus.
    When i run the TopHat (Rattus6.0.83/fr-firststrand/20 hits allowed per read/…) i obtain:

    Reads:
    Input : 29084606
    Mapped : 27577865 (94.8% of input)
    of these: 1284892 ( 4.7%) have multiple alignments (17957 have>20)
    94.8% overall read mapping rate.

    When running the HTSeq (Rattus6.0.83/"reverse"/no paired end/chromosome names in the BAM "1"/ union / exon / gene_id) for counting the reads per gene i found a lot of no_feature reads.

    __no_feature 7413760
    __ambiguous 111934
    __too_low_aQual 0
    __not_aligned 0
    __alignment_not_unique 4203664

    Is it normal?

    Then in the differential expression using the DESeq2 i get extremely few or even no significant padj values. Only get 12 signicant padj values even compairing MALES VH and FEMALES VH which seems quite shocking to us.
    I’m i doing something wrong?
    Thank you very much in advance for the help.

Latest Articles

Collapse

  • 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
  • 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

ad_right_rmr

Collapse

News

Collapse

Topics Statistics Last Post
Started by seqadmin, 04-11-2024, 12:08 PM
0 responses
18 views
0 likes
Last Post seqadmin  
Started by seqadmin, 04-10-2024, 10:19 PM
0 responses
22 views
0 likes
Last Post seqadmin  
Started by seqadmin, 04-10-2024, 09:21 AM
0 responses
16 views
0 likes
Last Post seqadmin  
Started by seqadmin, 04-04-2024, 09:00 AM
0 responses
47 views
0 likes
Last Post seqadmin  
Working...
X