Unconfigured Ad

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • cgjkjk
    Member
    • Oct 2008
    • 15

    #1

    A question about alignment depth

    What is the definition of 'alignment depth', it seems it is also called 'reads depth'? what information can be acquired from 'alignment depth'?

    Thanks.
  • apfejes
    Senior Member
    • Feb 2008
    • 236

    #2
    Essentially, it boils down to how many times each sequenced base is covered. The more depth, the more confidence you gain in your data.

    At the most basic level, most organisms I've worked with are diploid, so you get information about the SNPs present in the alleles (eg, homozygous or heterozygous.) I've seen various presentations where people have claimed that upwards of 50x coverage is required to truly required to really know if you have heterozygous SNPs, though what the minimum dept required really is depends on the technology and the method used to call SNPs.

    There are always inherent errors in the wet lab as well as the dry lab portions of any experiment. The more depth you get, the more support you get for your observations.

    Does that help?
    Last edited by apfejes; 01-14-2009, 09:04 AM. Reason: typo & clarity
    The more you know, the more you know you don't know. —Aristotle

    Comment

    • cgjkjk
      Member
      • Oct 2008
      • 15

      #3
      So helpful.
      Thanks million.

      Comment

      • inesdesantiago
        Member
        • Jan 2009
        • 44

        #4
        What is the difference between depth and coverage?
        When someone says that obtained 50X average coverage for a specific window, does this mean the depth?

        Comment

        • apfejes
          Senior Member
          • Feb 2008
          • 236

          #5
          Strictly speaking, I think they're exactly the same, but people often use them in different contexts, particularly with haploid/diploid organisms.

          When talking about a window, you can probably use them interchangeably.

          When talking about sequencing a SNP in a diploid organism, it's possible that you observe the SNP on one one half of the reads that map to a given point in the reference genome. Thus, you might have a depth of 50 at that point (50 reads cover that location), but the SNP itself has a coverage of 25X. (only half of the reads at that location have the SNP.)

          I'm sure there are people who will use them in the opposite manner as well.
          The more you know, the more you know you don't know. —Aristotle

          Comment

          • inesdesantiago
            Member
            • Jan 2009
            • 44

            #6
            Ok, thank you for the reply! It makes sense

            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
            25 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...