RESUMEN
ã We report on an infant with Opitz trigonocephaly C syndrome (OTCS), who also had manifestations of ciliopathy, including short ribs (non-asphyxiating), trident acetabular roofs, postaxial polydactyly cone-shaped epiphyses, and dysplasia of the renal, hepatic and pancreatic tissues. To investigate the molecular cause, we used an exome sequencing strategy followed by Sanger sequencing. Two rare variants, both predicted to result in loss of functional protein, were identified in the IFT140 gene; a substitution at the splice donor site of exon 24 (c.723 + 1 G > T) and a 17 bp deletion, impacting the first coding exon (c.-11_6del). The variants were confirmed as being biallelic using Sanger sequencing, showing that the splice variant was inherited from the propositus mother and the deletion from the father. To date, Mainzer-Saldino syndrome, Jeune syndrome, and a form of nonsyndromic retinal dystrophy, have been identified as ciliopathies caused by IFT140 mutations. We provide the first description of an OTCS phenotype that appears to result from IFT140 mutations. The presentation of this patient is consistent with previous reports showing that OTCS already exhibited skeleletal and nonskeletal features of a ciliopathy.
Asunto(s)
Proteínas Portadoras/genética , Ciliopatías/genética , Craneosinostosis/genética , Predisposición Genética a la Enfermedad , Discapacidad Intelectual/genética , Ciliopatías/diagnóstico , Ciliopatías/fisiopatología , Craneosinostosis/diagnóstico , Craneosinostosis/fisiopatología , Exoma/genética , Femenino , Heterocigoto , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Discapacidad Intelectual/diagnóstico , Discapacidad Intelectual/fisiopatología , Masculino , Linaje , Sitios de Empalme de ARN/genética , Eliminación de Secuencia/genéticaRESUMEN
Despite numerous systematic studies, the relationships among many species within the dog family, Canidae, remain unresolved. Two problems of broad evolutionary significance are the origins of the taxonomically rich canidae fauna of South America and the development in three species of the trenchant heel, a unique meat-cutting blade on the lower first molar. The first problem is of interest because the fossil record provides little evidence for the origins of divergent South American species such as the maned wolf and the bush dog. The second issue is problematic because the trenchant heel, although complex in form, may have evolved independently to assist in the processing of meat. We attempted to resolve these two issues and five other specific taxonomic controversies by phylogenetic analysis of 2,001 base pairs of mitochondrial DNA (mtDNA) sequence data from 23 canidae species. The mtDNA tree topology, coupled with data from the fossil record, and estimates of rates of DNA sequence divergence suggest at least three and possibly four North American invasions of South America. This result implies that an important chapter in the evolution of modern canids remains to be discovered in the fossil record and that the South American canidae endemism is as much the result of extinction outside of South America as it is due to speciation within South America. The origin of the trenchant heel is not well resolved by our data, although the maximum parsimony tree is weakly consistent with a single origin followed by multiple losses of the character in several extant species. A combined analysis of the mtDNA data and published morphological data provides unexpected support for a monophyletic South American canidae clade. However, the homogeneity partition tests indicate significant heterogeneity between the two data sets.
Asunto(s)
Carnívoros/clasificación , Carnívoros/genética , Filogenia , Animales , Secuencia de Bases , Carnívoros/anatomía & histología , Grupo Citocromo b/genética , ADN Mitocondrial/genética , Evolución Molecular , Datos de Secuencia Molecular , América del Norte , Homología de Secuencia de Ácido Nucleico , América del Sur , Diente/anatomía & histologíaRESUMEN
Filamentous bacteria isolated from surface-sterilized nodules of Casuarina equisetifolia trees in México were capable of reducing acetylene, a diagnostic test for nitrogenase, but were unable to nodulate their host. Analysis of partial 16S rRNA gene sequences suggests that the Mexican isolates are not Frankia strains but members of a novel clade.