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  • houhuabin
    Member
    • Apr 2009
    • 23

    #1

    Why there so many "n" in the UCSC humen genome fasta file.

    Who can tell me, please!
  • nilshomer
    Nils Homer
    • Nov 2008
    • 1283

    #2
    Originally posted by houhuabin View Post
    Who can tell me, please!
    Repeats that could not be assembled, regions that could not be cloned, and a lot of other reasons. I would review the original human genome project paper for more details.

    Comment

    • Rao
      Member
      • Oct 2008
      • 36

      #3
      there are some gaps (are represented in Ns)

      Comment

      • simonandrews
        Simon Andrews
        • May 2009
        • 870

        #4
        If you're just browsing the human genome sequence you may get a false impression of the content of Ns since there are huge streches of poly-N at both the telomeres and centromeres of every chromosome. These regions are particularly repetitive and almost impossible to assemble. The Ns on the end are just there so that the overall chromosome length shown is roughly correct.

        Other than that internal Ns are now relatively infrequent and generally represent short, highly repetitive regions.

        Compared to the assemblies of a lot of other vertebrate species though the human genome is very complete and accurate!

        Comment

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