Multilocus Sequence Typing analysis of human Campylobacter coli in Granada (Spain) / Tipificación mediante secuencias multilocus de cepas humanas de Campylobacter coli en Granada (España)

Introduction. Different subtypes of Campylobacter spp. have been associated with diarrhoea and a Multilocus Sequence Typing (MLST) method has been performed for subtyping. In the present work, MLST was used to analyse the genetic diversity of eight strains of Campylobacter coli. Material and methods. Nineteen genetic markers were amplified for MLST analysis: AnsB, DmsA, ggt, Cj1585c, CJJ81176-1367/1371, Tlp7, cj1321-cj1326, fucP, cj0178, cj0755/cfrA, ceuE, pldA, cstII, cstIII. After comparing the obtained sequences with the Campylobacter MLST database, the allele numbers, sequence types (STs) and clonal complexes (CCs) were assigned. Results. The 8 C. coli isolates yielded 4 different STs belonging to 2 CCs. Seven isolates belong to ST-828 clonal complex and only one isolate belong to ST-21. Two samples came from the same patient, but were isolated in two different periods of time. Conclusions. MLST can be useful for taxonomic characterization of C. coli isolates (AU)

Introducción. Diferentes subtipos de Campylobacter spp. se han asociado con diarrea y la técnica de tipado mediante análisis de secuencias de múltiples locus (MLST) se ha empleado para la tipificación genética. En el presente trabajo, la técnica MLST se utilizó para analizar la diversidad genética de ocho cepas de Campylobacter coli. Material y métodos. 19 marcadores genéticos fueron amplificados mediante el análisis MLST: AnsB, DmsA, ggt, Cj1585c, CJJ81176-1367/1371, Tlp7, cj1321-cj1326, fucP, cj0178, cj0755/cfrA, ceuE, pldA, cstII, cstIII. Después de comparar las secuencias obtenidas con la base de datos MLST para Campylobacter, se asignaron el número de los alelos, los secuenciotipos (STs) y los complejos clonales (CCs). Resultados. Las 8 cepas de C. coli aisladas mostraron 4 STs diferentes pertenecientes a 2 CCs. Siete aislamientos pertenecieron al complejo clonal ST-828 y sólo un aislado perteneció al ST-21. Dos aislados pertenecieron al mismo paciente, pero fueron obtenidos en diferentes periodos de tiempo. Conclusiones. La técnica MLST puede ser útil para la caracterización taxonómica de aislados de C. coli (AU)

Gene tree parsimony of multilocus snake venom protein families reveals species tree conflict as a result of multiple parallel gene loss.

The proliferation of gene data from multiple loci of large multigene families has been greatly facilitated by considerable recent advances in sequence generation. The evolution of such gene families, which often undergo complex histories and different rates of change, combined with increases in sequence data, pose complex problems for traditional phylogenetic analyses, and in particular, those that aim to successfully recover species relationships from gene trees. Here, we implement gene tree parsimony analyses on multicopy gene family data sets of snake venom proteins for two separate groups of taxa, incorporating Bayesian posterior distributions as a rigorous strategy to account for the uncertainty present in gene trees. Gene tree parsimony largely failed to infer species trees congruent with each other or with species phylogenies derived from mitochondrial and single-copy nuclear sequences. Analysis of four toxin gene families from a large expressed sequence tag data set from the viper genus Echis failed to produce a consistent topology, and reanalysis of a previously published gene tree parsimony data set, from the family Elapidae, suggested that species tree topologies were predominantly unsupported. We suggest that gene tree parsimony failure in the family Elapidae is likely the result of unequal and/or incomplete sampling of paralogous genes and demonstrate that multiple parallel gene losses are likely responsible for the significant species tree conflict observed in the genus Echis. These results highlight the potential for gene tree parsimony analyses to be undermined by rapidly evolving multilocus gene families under strong natural selection.