Ryan Joseph F.

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Ryan
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Joseph F.
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  • Article
    Meeting report of Ctenopalooza : the first international meeting of ctenophorologists
    (BioMed Central, 2016-08-25) Ryan, Joseph F. ; Schnitzler, Christine ; Tamm, Sidney L.
    Here we present a report on Ctenopalooza: A meeting of ctenophorologists held at the Whitney Laboratory for Marine Bioscience in St. Augustine, FL, USA, on March 14–15, 2016. In this report, we provide a summary of each of the sessions that occurred during this two-day meeting, which touched on most of the relevant areas of ctenophore biology. The report includes some major themes regarding the future of ctenophore research that emerged during Ctenopalooza. More information can be found at the meeting Web site: http://ctenopalooza.whitney.ufl.edu.
  • Article
    Genomic evidence for ameiotic evolution in the bdelloid rotifer Adineta vaga
    (Nature Publishing Group, 2013-07-21) Flot, Jean-Francois ; Hespeels, Boris ; Li, Xiang ; Noel, Benjamin ; Arkhipova, Irina R. ; Danchin, Etienne G. J. ; Hejno, Andreas ; Henrissat, Bernard ; Koszul, Romain ; Aury, Jean-Marc ; Barbe, Valerie ; Barthelemy, Roxane-Marie ; Bast, Jens ; Bazykin, Georgii A. ; Chabrol, Olivier ; Couloux, Arnaud ; Da Rocha, Martine ; Da Silva, Corinne ; Gladyshev, Eugene A. ; Gouret, Philippe ; Hallatschek, Oskar ; Hecox-Lea, Bette ; Labadie, Karine ; Lejeune, Benjamin ; Piskurek, Oliver ; Poulain, Julie ; Rodriguez, Fernando ; Ryan, Joseph F. ; Vakhrusheva, Olga A. ; Wajnberg, Eric ; Wirth, Benedicte ; Yushenova, Irina A. ; Kellis, Manolis ; Kondrashov, Alexey S. ; Mark Welch, David B. ; Pontarotti, Pierre ; Weissenbach, Jean ; Wincker, Patrick ; Jaillon, Olivier ; Van Doninck, Karine
    Loss of sexual reproduction is considered an evolutionary dead end for metazoans, but bdelloid rotifers challenge this view as they appear to have persisted asexually for millions of years1. Neither male sex organs nor meiosis have ever been observed in these microscopic animals: oocytes are formed through mitotic divisions, with no reduction of chromosome number and no indication of chromosome pairing2. However, current evidence does not exclude that they may engage in sex on rare, cryptic occasions. Here we report the genome of a bdelloid rotifer, Adineta vaga (Davis, 1873)3, and show that its structure is incompatible with conventional meiosis. At gene scale, the genome of A. vaga is tetraploid and comprises both anciently duplicated segments and less divergent allelic regions. However, in contrast to sexual species, the allelic regions are rearranged and sometimes even found on the same chromosome. Such structure does not allow meiotic pairing; instead, we find abundant evidence of gene conversion, which may limit the accumulation of deleterious mutations in the absence of meiosis. Gene families involved in resistance to oxidation, carbohydrate metabolism and defence against transposons are significantly expanded, which may explain why transposable elements cover only 3% of the assembled sequence. Furthermore, 8% of the genes are likely to be of non-metazoan origin and were probably acquired horizontally. This apparent convergence between bdelloids and prokaryotes sheds new light on the evolutionary significance of sex.