Association between translation efficiency and horizontal gene transfer within microbial communities

Horizontal gene transfer (HGT) is a major force in microbial evolution. Previous studies have suggested that a variety of factors, including restricted recombination and toxicity of foreign gene products, may act as barriers to the successful integration of horizontally transferred genes. This study identifies an additional central barrier to HGT—the lack of co-adaptation between the codon usage of the transferred gene and the tRNA pool of the recipient organism. Analyzing the genomic sequences of more than 190 microorganisms and the HGT events that have occurred between them, we show that the number of genes that were horizontally transferred between organisms is positively correlated with the similarity between their tRNA pools. Those genes that are better adapted to the tRNA pools of the target genomes tend to undergo more frequent HGT. At the community (or environment) level, organisms that share a common ecological niche tend to have similar tRNA pools. These results remain significant after controlling for diverse ecological and evolutionary parameters. Our analysis demonstrates that there are bi-directional associations between the similarity in the tRNA pools of organisms and the number of HGT events occurring between them. Similar tRNA pools between a donor and a host tend to increase the probability that a horizontally acquired gene will become fixed in its new genome. Our results also suggest that frequent HGT may be a homogenizing force that increases the similarity in the tRNA pools of organisms within the same community

Le sport en Israël-Palestine : un conflit désamorcé ?

International audienceThe sport sphere in Israel/Palestine has rarely become an explicit ethno-national battleground, even though Jews and Palestinians citizens of Israel. The article argues that since sport glorifies a meritocratic ethos it offers Arab players and fans some protection from the discriminatory practices they face in many other spheres of Israeli society. As a result sport has contributed to the maintenance of hegemonic structures and ideas and postponed national confrontations.Le sport en Israël-Palestine n’a jamais constitué un terrain de rivalité ethnique et national explicite, en dépit de la cohabitation des Juifs et des Palestiniens citoyens d’Israël. Cet article vise à démontrer que le sport, dans la mesure où il exalte un ethos méritocratique, préserve en partie les joueurs et supporters arabes des pratiques discriminatoires qu’ils peuvent subir dans d’autres sphères de la société israélienne. En retour, le sport contribua à maintenir les institutions hégémoniques et les idéaux des populations dominantes et il permit d’ajourner les confrontations nationales

MONUMENTOS CONMEMORATIVOS EN HOMENAJE A LOS MÁRTIRES (1976-1983) & (1998-2013)

En este artículo se plantea la complejidad que exige el análisis de la memoria nacional palestina tras ser interceptada por dos formas de colonialismo occidental; la del Mandato Británico a inicios del siglo XX, y la ocupación israelí que inició en 1948. Con la modernidad occidental colonial llegaron también las instancias de referencia por excelencia para conmemorar la memoria nacional, donde lo palestino no tuvo cabida sino hasta 1976, con la aparición de siete monumentos analizados. La segunda parte aborda un cambio radical, cuando, después de la Intifada del 2000 se multiplicó la construcción de monumentos conmemorativos palestinos, y su ubicación en lugares más visibles. La supervivencia de sólo uno de estos monumentos expone la dificultad del pueblo palestino que quedó dentro del Estado de Israel para congregar sus puntos de duelo colectivo, así como su reivindicación pública, enseñando la anulación identitaria y política a la que es sometido