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Papers by Pablo Daza
Nature, 2007
We report a high-quality draft of the genome sequence of the grey, short-tailed opossum (Monodelp... more We report a high-quality draft of the genome sequence of the grey, short-tailed opossum (Monodelphis domestica). As the first metatherian ('marsupial') species to be sequenced, the opossum provides a unique perspective on the organization and evolution of mammalian genomes. Distinctive features of the opossum chromosomes provide support for recent theories about genome evolution and function, including a strong influence of biased gene conversion on nucleotide sequence composition, and a relationship between chromosomal characteristics and X chromosome inactivation. Comparison of opossum and eutherian genomes also reveals a sharp difference in evolutionary innovation between protein-coding and non-coding functional elements. True innovation in protein-coding genes seems to be relatively rare, with lineage-specific differences being largely due to diversification and rapid turnover in gene families involved in environmental interactions. In contrast, about 20% of eutherian conserved non-coding elements (CNEs) are recent inventions that postdate the divergence of Eutheria and Metatheria. A substantial proportion of these eutherian-specific CNEs arose from sequence inserted by transposable elements, pointing to transposons as a major creative force in the evolution of mammalian gene regulation.
Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontology, 2011
Objective. The aim of this study was to describe the clinicopathologic and immunohistochemical ch... more Objective. The aim of this study was to describe the clinicopathologic and immunohistochemical characteristics of 14 cases of central odontogenic fibroma (COF), and the ultrastructural features of 2 of them. Study design. Collaborative retrospective study based on the records of 4 oral pathology diagnostic services in Latin America based on the current World Health Organization classification. Results. There were 7 male and 7 female patients (mean age 31.8 years). Eight tumors occurred in the maxilla and 6 in the mandible. Thirteen cases were epithelium-rich and 1 epithelium-poor COF. Three were classified as hybrid COF with giant cell lesion. Mean size of the hybrid lesions were larger than pure COF (3.8 vs. 2.4 cm). Odontogenic epithelial islands were immunoreactive for cytokeratin (CK) AE1/AE3, CK5, CK14, CK19, and 34BE12 and negative for CK1 and CK18. Langerhans cells positive for S-100 and CD1a were found within the epithelial islands in 6/6 tested cases. CD68 was expressed in the giant cells of the hybrid lesions and in a few mononuclear cells of 2 cases of COF. Ki-67 index was Ͻ1% in all cases. In 6 tumors (42.8%), there were small globular eosinophilic droplets within the epithelial islands, which were positive for collagen type IV, and 9/13 cases (69.2%) were focally positive for smooth muscle actin. In addition to fibroblasts, myofibroblastic differentiation was found in the 2 cases studied ultrastructurally. Conclusions. Immunohistochemistry was useful to confirm the presence of epithelium and to exclude other central fibrous tumors. COF also contains a variable number of mast cells, Langerhans cells, and myofibroblasts, and further studies are needed to better understand the participation of these cells in COF histogenesis.
Crop Science, 1978
Abstract An analysis of genetic variability in several populations of cassava (Manihot esculenta ... more Abstract An analysis of genetic variability in several populations of cassava (Manihot esculenta Crantz) revealed that it is a highly heterozygous species. This species is monoecious, and no genetic or physiological barrier to prevent self-fertilization was found. ...
Crop Science, 1978
Se realizo una evaluacion en Colombia del rendimiento de aprox 1900 accesiones de Manihot Esculen... more Se realizo una evaluacion en Colombia del rendimiento de aprox 1900 accesiones de Manihot Esculenta recolectadas en toda America Latina y 4700 lineas hibridas de cruzamiento con este germoplasma, en parcelas de un solo surco. Se seleccionaron genotipos superiores con ...
Nature, 2007
We report a high-quality draft of the genome sequence of the grey, short-tailed opossum (Monodelp... more We report a high-quality draft of the genome sequence of the grey, short-tailed opossum (Monodelphis domestica). As the first metatherian ('marsupial') species to be sequenced, the opossum provides a unique perspective on the organization and evolution of mammalian genomes. Distinctive features of the opossum chromosomes provide support for recent theories about genome evolution and function, including a strong influence of biased gene conversion on nucleotide sequence composition, and a relationship between chromosomal characteristics and X chromosome inactivation. Comparison of opossum and eutherian genomes also reveals a sharp difference in evolutionary innovation between protein-coding and non-coding functional elements. True innovation in protein-coding genes seems to be relatively rare, with lineage-specific differences being largely due to diversification and rapid turnover in gene families involved in environmental interactions. In contrast, about 20% of eutherian conserved non-coding elements (CNEs) are recent inventions that postdate the divergence of Eutheria and Metatheria. A substantial proportion of these eutherian-specific CNEs arose from sequence inserted by transposable elements, pointing to transposons as a major creative force in the evolution of mammalian gene regulation.
Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontology, 2011
Objective. The aim of this study was to describe the clinicopathologic and immunohistochemical ch... more Objective. The aim of this study was to describe the clinicopathologic and immunohistochemical characteristics of 14 cases of central odontogenic fibroma (COF), and the ultrastructural features of 2 of them. Study design. Collaborative retrospective study based on the records of 4 oral pathology diagnostic services in Latin America based on the current World Health Organization classification. Results. There were 7 male and 7 female patients (mean age 31.8 years). Eight tumors occurred in the maxilla and 6 in the mandible. Thirteen cases were epithelium-rich and 1 epithelium-poor COF. Three were classified as hybrid COF with giant cell lesion. Mean size of the hybrid lesions were larger than pure COF (3.8 vs. 2.4 cm). Odontogenic epithelial islands were immunoreactive for cytokeratin (CK) AE1/AE3, CK5, CK14, CK19, and 34BE12 and negative for CK1 and CK18. Langerhans cells positive for S-100 and CD1a were found within the epithelial islands in 6/6 tested cases. CD68 was expressed in the giant cells of the hybrid lesions and in a few mononuclear cells of 2 cases of COF. Ki-67 index was Ͻ1% in all cases. In 6 tumors (42.8%), there were small globular eosinophilic droplets within the epithelial islands, which were positive for collagen type IV, and 9/13 cases (69.2%) were focally positive for smooth muscle actin. In addition to fibroblasts, myofibroblastic differentiation was found in the 2 cases studied ultrastructurally. Conclusions. Immunohistochemistry was useful to confirm the presence of epithelium and to exclude other central fibrous tumors. COF also contains a variable number of mast cells, Langerhans cells, and myofibroblasts, and further studies are needed to better understand the participation of these cells in COF histogenesis.
Crop Science, 1978
Abstract An analysis of genetic variability in several populations of cassava (Manihot esculenta ... more Abstract An analysis of genetic variability in several populations of cassava (Manihot esculenta Crantz) revealed that it is a highly heterozygous species. This species is monoecious, and no genetic or physiological barrier to prevent self-fertilization was found. ...
Crop Science, 1978
Se realizo una evaluacion en Colombia del rendimiento de aprox 1900 accesiones de Manihot Esculen... more Se realizo una evaluacion en Colombia del rendimiento de aprox 1900 accesiones de Manihot Esculenta recolectadas en toda America Latina y 4700 lineas hibridas de cruzamiento con este germoplasma, en parcelas de un solo surco. Se seleccionaron genotipos superiores con ...