RESUMEN
Background: Yersinia pestis, a Gram-negative bacterium, is the causative agent of plague. Y. pestis is a zoonotic pathogen that occasionally infects humans and became endemic in the western United States after spreading from California in 1899. Methods: To better understand evolutionary patterns in Y. pestis from the southwestern United States, we sequenced and analyzed 22 novel genomes from New Mexico. Analytical methods included, assembly, multiple sequences alignment, phylogenetic tree reconstruction, genotype-phenotype correlation, and selection pressure. Results: We identified four genes, including Yscp and locus tag YPO3944, which contained codons undergoing negative selection. We also observed 42 nucleotide sites displaying a statistically significant skew in the observed residue distribution based on the year of isolation. Overall, the three genes with the most statistically significant variations that associated with metadata for these isolates were sapA, fliC, and argD. Phylogenetic analyses point to a single introduction of Y. pestis into the United States with two subsequent, independent movements into New Mexico. Taken together, these analyses shed light on the evolutionary history of this pathogen in the southwestern US over a focused time range and confirm a single origin and introduction into North America.
Asunto(s)
Peste , Yersinia pestis , Humanos , Yersinia pestis/genética , Filogenia , New Mexico/epidemiología , Peste/epidemiología , Análisis de SecuenciaRESUMEN
Three new species of the genus Longior Travassos Kloss, 1958 are described and illustrated, namely L. surieli n. sp. in Antillanax dominicanus (Doesburg, 1953) from the Dominican Republic, L. lamothei n. sp. in Passalus punctiger Le Peletier Serville, 1825 from Mexico and Colombia and L. zumpimito n. sp. in P. punctatostriatus Percheron, 1835 from Mexico. These constitute the first records of the genus Longior for the aforementioned countries, rising to nine species in the genus. The new species can be differentiated mainly by the length of their body, oesophagus and tail in both sexes, the extension of the lateral alae in the females and the morphology of the cephalic and posterior end in the males. The molecular phylogeny of the new taxa is inferred by the 28S and 18S rDNA and they form a monophyletic clade with other Longior species. The phylogeny of Longior and that of their passalid hosts reveal coevolutionary relationships. These patterns suggest that the phylogeny of Longior species is probably strongly influenced by the evolutionary trajectories of their passalid hosts.
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Escarabajos , Nematodos , Parásitos , Animales , Colombia , República Dominicana , Femenino , Masculino , México , FilogeniaRESUMEN
Coynema poeyi (Coy, García Álvarez, 1993) (Oxyuridomorpha: Hystrignathidae) is redescribed and illustrated with the aid of SEM. New features of the cephalic end of both sexes and copulatory papillae pattern of the males were observed and the generic diagnosis is emended in order to include such features. New locality records are given. The phylogenetic position of the species is inferred on the basis of the D2-D3 segment of the LSU rDNA. C. poeyi is located basal in a monophyletic clade formed by other hystrignathids: two species of Longior Travassos Kloss, 1958 and Hystrignathus sp.
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Escarabajos , Filogenia , Animales , Cuba , Femenino , Masculino , OxyuridaRESUMEN
The status of Longior alius García Coy, 1994 (Nematoda: Thelastomatoidea: Hystrignathidae) is discussed on the basis of new material obtained from its type host Antillanax pertyi (Kaup, 1869) (Coleoptera: Passalidae) from Limonar, Guantánamo province, Cuba, near the type locality. Based on morphological and molecular studies L. alius is considered synonymous with L. longior Morffe García, 2011. L. longior and L. similis Morffe, García Ventosa, 2009 are redescribed and illustrated with the aid of SEM. New locality records for both species are given. The conspecificity of females and males of both species is supported by comparison of the D2-D3 segment of the 28S LSU rDNA. The inter-specific differences and phylogenetic position of L. longior and L. similis are discussed.
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Oxyurida , Animales , Cuba , ADN Ribosómico , Femenino , Masculino , Nematodos , FilogeniaRESUMEN
In this study, we used a recently developed supertrees method to test for shared phylogeographical signal in partially overlapping geographical ranges of lizards of the genus Liolaemus from the Andean Range in south-central Chile. We reconstruct mtDNA gene trees for three partially codistributed species (Liolaemus tenuis, L. lemniscatus and L. pictus), and our sampling effort is sufficient to allow statistical tests of shared signal between the combinations L. tenuis-L. pictus, and L. tenuis-L. lemniscatus. For both combinations, standardized maximum agreement subtrees scores showed statistically significant signal for shared pattern in regions of overlap, as evaluated by randomization tests (P < 0.001 and < 0.05, respectively). The matrix representation with parsimony tree obtained from the combination of the three different gene trees revealed concordant phylogeographical associations of all species, and was consistent with the geographical association of intraspecific haploclades with three Chilean bioclimatic zones. A multidimensional scaling analysis of several climate variables showed highly significant differences among these zones, which further suggests that they may have contributed to similar patterns of intraspecific divergence across all three species. In the mesomorphic zone in Central Chile, the species L. tenuis and L. lemniscatus may have codiverged in response to shared orogenic vicariant events, which likely predominated over climatic events associated with cycles of glacial advance and retreat. In the hygromorphic zone in southern Chile, however, glacial cycles likely predominated in structuring the phylogeographical histories of L. tenuis and L. pictus, although important ecological differences between these two caution against broad generalizations at this point.
Asunto(s)
Citocromos b/genética , ADN Mitocondrial/genética , Variación Genética , Lagartos/genética , Filogenia , Secuencia de Aminoácidos , Animales , Chile , Geografía , Haplotipos , Datos de Secuencia Molecular , Alineación de Secuencia , Análisis de Secuencia de ADNRESUMEN
Amplified fragment length polymorphism (AFLP) was used to investigate polymorphism among 43 Hirsutella thompsonii isolates (33 from Thailand) obtained from various mite species. The outgroups were an unidentified Hirsutella isolate along with Hirsutella nodulosa and Hirsutella kirchneri. Phylogenetic analyses of the AFLP data showed significant variation among isolates and the existence of three H. thompsonii clades. We also investigated the isolates using PCR with specific primers for the Hirsutella exotoxin gene Hirsutelin A (HtA) and 18 of these isolates were used for sequencing of the partial beta-tubulin gene. Phylogenetic analyses of beta-tubulin sequences showed two distinct H. thompsonii clades, one of which included AFLP clades I and II. For both markers grouping of the H. thompsonii isolates was not related to either host mite species or geographical origin, although for the HtA gene one clade contained only isolates with no detectable HtA band. These results confirm the high intraspecific polymorphism of H. thompsonii, and maximum likelihood analysis showed no monophyletic group within this species. To refine the taxonomy of this genus other studies should be undertaken using additional molecular markers and several other Hirsutella isolates.