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A comprehensive analysis of reassortment in influenza A virus

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  • A comprehensive analysis of reassortment in influenza A virus

    Biol Open. 2012 Apr 15;1(4):385-90. doi: 10.1242/bio.2012281. Epub 2012 Feb 16.
    A comprehensive analysis of reassortment in influenza A virus.
    de Silva UC, Tanaka H, Nakamura S, Goto N, Yasunaga T.
    Source

    Department of Genome Informatics ; World Premier International Immunology Frontier Research Centre, Osaka University , Osaka 565-0871 , Japan.
    Abstract

    Genetic reassortment plays a vital role in the evolution of the influenza virus and has historically been linked with the emergence of pandemic strains. Reassortment is believed to occur when a single host - typically swine - is simultaneously infected with multiple influenza strains. The reassorted viral strains with novel gene combinations tend to easily evade the immune system in other host species, satisfying the basic requirements of a virus with pandemic potential. Therefore, it is vital to continuously monitor the genetic content of circulating influenza strains and keep an eye out for new reassortants. We present a new approach to identify reassortants from large data sets of influenza whole genome nucleotide sequences and report the results of the first ever comprehensive search for reassortants of all published influenza A genomic data. 35 of the 52 well supported candidate reassortants we found are reported here for the first time while our analysis method offers new insight that enables us to draw a more detailed picture of the origin of some of the previously reported reassortants. A disproportionately high number (13/52) of the candidate reassortants found were the result of the introduction of novel hemagglutinin and/or neuraminidase genes into a previously circulating virus. The method described in this paper may contribute towards automating the task of routinely searching for reassortants among newly sequenced strains.

    PMID:
    23213428
    [PubMed - in process]

    Genetic reassortment plays a vital role in the evolution of the influenza virus and has historically been linked with the emergence of pandemic strains. Reassortment is believed to occur when a single host - typically swine - is simultaneously infected with multiple influenza strains. The reassorted …

  • #2
    Re: A comprehensive analysis of reassortment in influenza A virus



    > We present a new approach to identify reassortants from large
    > data sets of influenza whole genome nucleotide sequences and
    > report the results of the first ever comprehensive search for
    > reassortants of all published influenza A genomic data

    > 35 of the 52 well supported candidate reassortants we found are reported here
    > for the first time
    > All available full genome influenza A nucleotide sequences (as at 24th June 2011)
    > 9284 sequences for each segment
    > highly similar genome sequences (>97% in HA and NA; >98% in all other segments
    > simultaneously) were removed
    > ...16 hours ...
    > final dataset of 1670 representative sequences



    I did it in 2008
    here my list for 1119 avian segments 1,2


    my program reassa.exe had been uploaded to magictour:



    C-sourcecode attached to the (Windows-16-bit,GCC 3.2) executables, as usual


    Verzeichnis von E:\seq
    26.01.2008 21:07 67.024 reassa.exe
    24.03.2008 19:56 67.226 reass.exe
    29.02.2008 14:44 71.306 reassi.exe
    25.08.2008 09:35 67.098 reassak.exe
    4 Datei(en) 272.654 Bytes

    afair this was derived from a recombination-searching program with fixed breakpoints

    testing again ... takes 35sec for 400 avian genomes separating seg.1 and 2
    so max 28*35sec for all segments and 25*25 fold for all ~10000 avian genomes
    = 612500sec = 1 week fror 10000 genomes , 1h for 1000 genomes
    -----------------------------------------------------

    FluShuffle and FluResort: new algorithms to identify reassorted
    ---------------------------------------------------------

    per March,10,2013 genbank has 4564 avian genomes,7368 human flu-A genomes,
    86 equine genomes and 1054 swine genomes.

    4500 avian genomes in file avg13
    reass.exe avg13 1 2 takes 105 min and creates the file kk of size 313 MB
    which is sorted (<5min) and processed with rec8c.bas(<5min) to remove sequence pairs with one
    of the sequences already used..That leaves a file of

    that was for comparing segments 1 and 2 only. There are 27 other combinations ...


    -----------------------------------------------------------------------------

    I'm dreaming of a software, that displays mutation pics for 8 segments
    click on a segment to sort by that segment (solve TSP approx.)
    zoom in,out with fingers as on tablets,ipads
    ignore segments by double-click (HA,NA)
    horizontal search on one click (or finger-tip)

    maybe even on a big screen with 5000*5000 viewable pixels

    mark collection dates,hosts,countries on the right bars
    filter in/out on segments,hosts,countries,continents, clickable parts

    mark (blink) reassortments and recombinations and stasis

    clouds for dS,dN,T , calculate and display tmrca
    display earliest for a set of markers
    calculate/create/add consensus sequences (average) for bottlenecks,reassortment-events

    update the databases automatically

    it will come, because it makes sense , but when ?
    I'm interested in expert panflu damage estimates
    my current links: http://bit.ly/hFI7H ILI-charts: http://bit.ly/CcRgT

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