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- Irestedt, Martin, et al.
(författare)
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Phylogeny of major lineages of suboscines (Passeriformes) analysed by nuclear DNA sequence data
- 2001
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Ingår i: Journal of Avian Biology. - : Blackwell. - 0908-8857 .- 1600-048X. ; 32:1, s. 15-25
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Tidskriftsartikel (refereegranskat)abstract
- Phylogenetic relationships among major groups of passeriform birds were studied by analyses of nucleotide sequence data from two nuclear genes, c-myc and RAG-1. The results corroborated both the monophyly of the order Passeriformes, and the major dichotomy into oscine and suboscine passerines previously suggested based on syringeal morphology and DNA-DNA hybridizations. The representatives of the Old World suboscines (families Eurylaimidae, Philepittidae and Pittidae) formed a monophyletic clade. The New World suboscines clustered into two clades. The first contained Conopophaga (Conopophagidae), Furnarius (Furnariidae), Lepidocolaptes (Dendrocolaptidae), Thamnophilus (Formicariidae), and Rhinocrypta (Rhinocryptidae). Previously, the monophyly of this group has been inferred from their possession of a unique, "tracheophone" syrinx, and from DNA-DNA hybridisation data. The second clade of New World suboscines includes Gubernetes and Muscivora (Tyrannidae), Phytotoma (Phytotomidae), Tityra (Cotingidae) and Pipra (Pipridae). This group of families have been considered monophyletic based on morphology (although ambiguously) and DNA-DNA hybridisation. The sister group relationship of Tityra and Phytotoma supports the previously supposed cotingid affinity of Phytotoma. Nuclear DNA data also unambiguously group the lyrebirds Menura with the oscines. The presented results from the analysis of nuclear DNA agree well with morphology and DNA-DNA hybridisation data. The precise age of the divergences studied herein are unknown but based on interpretations of the fossil record of passerine birds many of them might date back to the early Tertiary. The agreement between data from the nuclear DNA and other sources, along with the fact that neither of the studied genes showed sign of saturation, indicate the great potential of these two nuclear genes to resolve very old divergences in birds.
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- Johansson, Ulf S, et al.
(författare)
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Basal phylogeny of the Tyrannoidea based on comparisons of cytochrome b and exons of nuclear c-myc and RAG-1 genes
- 2002
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Ingår i: The AUK. - 0004-8038 .- 1938-4254. ; 119:4, s. 984-995
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Tidskriftsartikel (refereegranskat)abstract
- The outlines of the phylogenetic relationships within the New World suboscine clade Tyrannoidea were investigated on the basis of nucleotide sequence data from two nuclear genes (c-myc and RAG-1) and one mitochondrial gene (cytochrome b), totaling over 2,400 bp. Representatives of the major tyrannoid lineages were sequenced, including Pachyramphus, Schiffornis, Tityra, and Oxyruncus. The data set with the three genes combined was analyzed under both the parsimony and maximum-likelihood criteria and under different character weighting schemes. The analyses resulted in similar topologies that differed only in poorly supported nodes. The three manakins (Pipra, Manacus, and Chiroxiphia) included in this study were found to be monophyletic, whereas Schiffornis—sometimes also considered to be a manakin—did not group with the manakins, but occurred with Pachyramphus and Tityra in the clade Tityrinae. The two clades Pipromorphinae and Tyranninae are also strongly supported in this analysis and appear as sister groups, thus supporting the monophyly of the tyrant flycatcher assemblage. Phytotoma was placed with the only cotingid species included in this analysis, whereas the position of Oxyruncus was unresolved.
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- Johansson, Ulf S, et al.
(författare)
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Clades within the 'higher land birds', evaluated bg nuclear DNA sequences
- 2001
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Ingår i: Journal of Zoological Systematics and Evolutionary Research. - 0947-5745 .- 1439-0469. ; 39:1-2, s. 37-51
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Tidskriftsartikel (refereegranskat)abstract
- In this study we investigated the phylogenetic relationships within the 'higher land birds' by parsimony analysis of nucleotide DNA sequences obtained from the two nuclear, protein-coding genes, c-myc and RAG-I. Nuclear genes have not previously been used to address this phylogenetic question. The results include high jackknife support for a monophyletic Apodiformes (including the Trochilidae). This arrangement was further supported by the observation of an insertion of four amino acids in the c-myc gene in all apodiform taxa. Monophyly was also inferred for each of the two piciform groups Galbulae and Pici. Within Pici, the Capitonidae was found to be paraphyletic, with the New World barbers more closely related to the Ramphastidae than to the Old World barbers. Another clade with high jackknife support consists of the Upupidae, Phoeniculidae and Bucerotidae. The families Momotidae and Todidae, and Coraciidae and Brachypteraciidae, respectively, also form well supported monophyletic clades. The results are inconclusive regarding the monophyly of the orders Coraciiformes and Piciformes, respectively.
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- Pavey, S, et al.
(författare)
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Microarray expression profiling in melanoma reveals a BRAF mutation signature
- 2004
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Ingår i: Oncogene. - : Springer Science and Business Media LLC. - 1476-5594 .- 0950-9232. ; 23:23, s. 4060-4067
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Tidskriftsartikel (refereegranskat)abstract
- We have used microarray gene expression pro. ling and machine learning to predict the presence of BRAF mutations in a panel of 61 melanoma cell lines. The BRAF gene was found to be mutated in 42 samples (69%) and intragenic mutations of the NRAS gene were detected in seven samples (11%). No cell line carried mutations of both genes. Using support vector machines, we have built a classifier that differentiates between melanoma cell lines based on BRAF mutation status. As few as 83 genes are able to discriminate between BRAF mutant and BRAF wild-type samples with clear separation observed using hierarchical clustering. Multidimensional scaling was used to visualize the relationship between a BRAF mutation signature and that of a generalized mitogen-activated protein kinase ( MAPK) activation ( either BRAF or NRAS mutation) in the context of the discriminating gene list. We observed that samples carrying NRAS mutations lie somewhere between those with or without BRAF mutations. These observations suggest that there are gene-specific mutation signals in addition to a common MAPK activation that result from the pleiotropic effects of either BRAF or NRAS on other signaling pathways, leading to measurably different transcriptional changes.
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- Spring, Frances A., et al.
(författare)
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Intercellular adhesion molecule-4 binds alpha(4)beta(1) and alpha(V)-family integrins through novel integrin-binding mechanisms
- 2001
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Ingår i: Blood. - 1528-0020. ; 98:2, s. 458-466
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Tidskriftsartikel (refereegranskat)abstract
- The LW blood group glycoprotein, ICAM-4, is a member of the intercellular adhesion molecule (ICAM) family expressed in erythroid cells. To begin to address the function of this molecule, ligands for ICAM-4 on hemopoietic and nonhemopoietic cell lines were identified. Peptide inhibition studies suggest that adhesion of cell lines to an ICAM-4-Fc construct is mediated by an LDV-inhibitable integrin on hemopoietic cells and an RGD-inhibitable integrin on nonhemopoietic cells. Antibody inhibition studies identified the hemopoietic integrin as alpha(4)beta(1.) Antibody inhibition studies on alpha(4)beta(1)-negative, nonhemopoietic cell lines suggested that adhesion of these cells is mediated by alpha(V) integrins (notably alpha(V)beta(1) and alpha(V)beta(5)). The structure of ICAM-4 modeled on the crystal structure of ICAM-2 was used to identify surface-exposed amino acid residues for site-directed mutagenesis. Neither an unusual LETS nor an LDV motif in the first domain of ICAM-4 was critical for integrin binding. ICAM-4 is the first ICAM family member shown to be a ligand for integrins other than those of the beta(2) family, and the data suggest that ICAM-4 has a novel integrin-binding site(s). These findings suggest a role for ICAM-4 in normal erythropoiesis and may also be relevant to the adhesive interactions of sickle cells.
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