5 research outputs found

    Molecular systematics of teioid lizards (Teioidea/Gymnophthalmoidea: Squamata) based on the analysis of 48 loci under tree-alignment and similarity-alignment

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    We infer phylogenetic relationships within Teioidea, a superfamily of Nearctic and Neotropical lizards, using nucleotide sequences. Phylogenetic analyses relied on parsimony under tree-alignment and similarity-alignment, with length variation (i.e. gaps) treated as evidence and as absence of evidence, and maximum-likelihood under similarity-alignment with gaps as absence of evidence. All analyses produced almost completely resolved trees despite 86% of missing data. Tree-alignment produced the shortest trees, the strict consensus of which is more similar to the maximum-likelihood tree than to any of the other parsimony trees, in terms of both number of clades shared, parsimony cost and likelihood scores. Comparisons of tree costs suggest that the pattern of indels inferred by similarity-alignment drove parsimony analyses on similarity-aligned sequences away from more optimal solutions. All analyses agree in a majority of clades, although they differ from each other in unique ways, suggesting that neither the criterion of optimality, alignment nor treatment of indels alone can explain all differences. Parsimony rejects the monophyly of Gymnophthalmidae due to the position of Alopoglossinae relative to Teiidae, whereas support of Gymnophthalmidae by maximum-likelihood was low. We address various nomenclatural issues, including Gymnophthalmidae Fitzinger, 1826 being an older name than Teiidae Gray, 1827. We recognize three families in the arrangement Alopoglossidae + (Teiidae + Gymnophthalmidae). Within Gymnophthalmidae we recognize Cercosaurinae, Gymnophthalminae, Rhachisaurinae and Riolaminae in the relationship Cercosaurinae + (Rhachisaurinae + (Riolaminae + Gymnophthalminae)). Cercosaurinae is composed of three tribes—Bachiini, Cercosaurini and Ecpleopodini—and Gymnophthalminae is composed of three—Gymnophthalmini, Heterodactylini and Iphisini. Within Teiidae we retain the currently recognized three subfamilies in the arrangement: Callopistinae + (Tupinambinae + Teiinae). We also propose several genus-level changes to restore the monophyly of taxa.This study was funded by the Spanish Ministry of Science and Innovation Projects CGL2008-04164 and CLG2011-30393 (I. De La Riva, PI), and CGL2010-21250 and CGL2011-30393 (Carles Vila, PI),Peer Reviewe

    Smectites and related silicates

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    A highly virulent variant of HIV-1 circulating in the Netherlands.

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    We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log <sub>10</sub> increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence
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