domingo, 28 de agosto de 2011
Phylogeny of Tabaninae: A critique to Abu El-Hassan et al. (2010)
Materials and methods
under implicit weights
Concavity value | Average of the shared consensus nodes |
1 | 0,5789 |
2 | 0,5789 |
3 | 0,6316 |
4 | 0,6842 |
5 | 0,6316 |
6 | 0,6316 |
7 | 0,6316 |
8 | 0,7895 |
9 | 0,8421 |
10 | 0,7895 |
EVALUATION OF THE GEOGRAPHIC STRUCTURE IN DENGUE VIRUS TYPE 1 FROM A PHYLOGENETIC AND BIOGEOGRAPHIC APPROACH
METHODS
Phylogenetic analysis of 50 DENV-1 E gene sequences were assess from the Bayesian inference criterion using BEAST v1.6.2 program (Drummond & Rambaut, 2007), under a General Time Reversible model of nucleotide substitution (Rodriguez et al.,1990) with gamma-distributed rate variation and a proportion of invariable sites (GTR + G + I) were selected and two runs of 4 chains were run for ten millions of generations. Sequences were sampled in American counties, including islands in the Atlantic and Pacific Oceans
Finally, the geographic patterns were evaluated following the method of track compatibility by Craw (1988a, 1989a). The areas used were those postulated in this work and the biotic components of Latin America and the Caribbean compiled by Morrone (2004). under the level of large regions and provinces.
RESULTS AND DISCUSSION
The phylogenetic relationchips from American sequences seems to be structured by geographics patterns. According with this, five areas were proposed corresponding to Pacific, Caribbean, southern South America, central América and Northern south America. These components were determined following the geographic information available to each viral isolated. Intuitively, central and Northern south America were taken as independent unities.
Figure 1. Maximum clade credibility tree in Bayesian analysis of E
gene sequences representing Latin America strains. Posterior probabilities are shown for key nodes.Figure 2. Phylogeographic patterns between genotypes and postulated areas in Dengue virus type 1
Tracks compatibility analysis resulted in a clique (based in regions) representing a pattern that related Mexican transition area with Neotropical Region, which is congruent with the relationship between SAN and CA areas in phylogeographic analysis. This is probably due to the magnitud of the areas which includes a higher proportion of distributions and strains that are distribuited in intermediate areas. Areas delimited as Provinces by Morrone (2004) and phylogeographic areas delimited here, do not showed compatible traks.
Figure 3. Traks compatibility analysis. a) Areas proposed in this study. Biotic components of Latin America and the Caribbean b) Provinces c) Regions.
CONCLUSION
Phylogenetic and Biogeographic analysis in dengue virus can reflect a similar geographic pattern however is necessary to know the level in which both approaches can be congruent. In this study, Central America and northern South America form a large unit that corresponds to the clique found in the track compatibility analysis, which supports the close relationship between the Mexican transition area and the Neotropical region. Obviously, the use of geopolitical units in the assessment of geographical structure in shaping the phylogenetic relationships dengue is not the most accurate and dengue virus strains behave as a large dispersive population connecting large areas in America.
REFERENCES
Carvalho SE, Martin DP, Oliveira LM, Ribeiro BM, Nagata T (2010) Comparative analysis of American Dengue virus type 1 full-genome sequences. Virus Genes 40: 60–66.
CRAW, R. C. 1988. Continuing the synthesis between panbiogeography, p
hylogenetic systematics and geology as illustrated by empirical studies on the biogeography of New Zealand and the Cha tham Islands. Systematic Zoology 37: 291-310.
CRAW, R. C. 1989a. New Zealand biogeography: A panbiogeographic approach. New Zealand Journal of Zoology 16: 527-547
Drummond AJ & Rambaut A (2007) "BEAST: Bayesian evolutionary analysis by sampling trees." BMC Evolutionary Biology 7, 214
Samuel, A. R., Knowles, N. J. 2001. Foot-and-mouth disease type O viruses exhibit genetically and geographically distinct evolutionary lineages (topotypes). Journal of General Virology 74, 2281-2285.