RESUMEN
Spermatogonial and metaphase I chromosomes of the lumbricid earthworm Octodrilus complanatus (Annelida: Oligochaeta) were examined using fluorescent in situ hybridization (FISH) with three repetitive DNA probes-5S rDNA, 18S-26S rDNA, and (TTAGGG)(n). Single-color FISH consistently mapped one chromosome pair per spread using either 5S rDNA or 18S-26S rDNA as probes. Simultaneous (18S-26S)-5S and (18S-26S)-(TTAGGG)(n) FISH demonstrated that repeated units of the two ribosomal families were overlapped and closely associated with telomeric sequences.
Asunto(s)
ADN Ribosómico , Ligamiento Genético , Oligoquetos/genética , Telómero , Animales , Hibridación Fluorescente in SituRESUMEN
Careful quantitative analyses by spot hybridization to homologous probes demonstrate that no rDNA amplification occurs during Paracentrotus lividus oogenesis. The same approach was used to measure the copy number of the genes involved in ribosome biogenesis. Surprisingly, differently from the organisms in which the lack of rDNA amplification phenomena was observed, a very low number of constitutive rDNA repeats was found in this organism.
Asunto(s)
Amplificación de Genes , Dosificación de Gen , ARN Ribosómico/genética , Erizos de Mar/fisiología , Animales , Femenino , Masculino , Hibridación de Ácido Nucleico , Oocitos/química , Oogénesis/genética , ARN Ribosómico/análisis , Espermatozoides/químicaRESUMEN
In the present study, somatic metaphase chromosomes of the millipede Enologus oxypygum (Diplopoda: Julida) were hybridized in situ with a sea urchin (Echinodermata) ribosomal probe (prR14) in order to map major RNA genes (rDNA). Chromosomal preparations were also silver stained (Ag-NOR) to evaluate the rDNA transcriptional activity. Our results indicate that RNA genes are throughout heterochromatin in eight chromosomes involving 1/4 of the total heterochromatin which, in this species, is about 67% of the total DNA. Ag-NOR and FISH patterns were not coincident.
Asunto(s)
Artrópodos/genética , ARN Ribosómico 18S/genética , ARN Ribosómico 28S/genética , Animales , ADN Ribosómico/genética , Heterocromatina/genética , Hibridación Fluorescente in SituRESUMEN
This paper reports on a successful application of fluorescent in situ hybridization (FISH) with three repetitive DNA probes (ribosomal DNA (rDNA), (GATA)n and (TTAGGG)n) in the chromosomes of Fasciolaria lignaria (Mollusca: Prosobranchia: Neogastropoda). rDNA FISH consistently identified four chromosome pairs per spread in the three examined specimens. The telomeric sequence (TTAGGG)n hybridized with termini of all chromosomes. GATA FISH revealed abundant, dispersed minisatellite regions which were not associated to the XY sex-determining mechanism as indicated by the absence of a Y specific pattern of labelling.
Asunto(s)
Cromosomas/genética , ADN Ribosómico/genética , Moluscos/genética , Animales , Secuencia de Bases , Mapeo Cromosómico , Sondas de ADN/genética , Femenino , Hibridación Fluorescente in Situ , Masculino , Repeticiones de Minisatélite , Procesos de Determinación del Sexo , Telómero/genéticaRESUMEN
The presence of the alpha alpha alpha anti-4.2 haplotype and heterozygous beta null thalassemia in a Sicilian family is described. These findings confirm the presence in Italy of a leftward deletion (-alpha 4.2) and indicate that this may not be rare. Furthermore, although the beta thalassemia determinant in this family has a severe expression, the interaction with the triplicated alpha gene does not necessarily express itself as thalassemia intermedia.
Asunto(s)
Globinas/genética , Talasemia/genética , Adulto , Deleción Cromosómica , Femenino , Amplificación de Genes , Genotipo , Heterocigoto , Humanos , Italia , Masculino , Embarazo , Talasemia/sangreRESUMEN
It is shown that the RNA of unfertilized sea urchin eggs is active in stimulating protein synthesis in a wheat germ cell free system. This activity is not lowered by conditions that inhibit the methylation processes but is inhibited by a treatment that damages the "cap", A difference in activity in a wheat germ cell free system between the RNA of unfertilized eggs and the RNA from early embryos is described.