RESUMEN
Restriction endonuclease in situ digestion of metaphase chromosomes gives an opportunity to reveal strips with different structure within GC-rich pericentric heterochromatin of the domestic horse and the wild Przewalski horse. Blocks of heterochromatin, which are insensitive to HaeIII and brightly stained with chromomycin A3 after restriction enzyme digestion, are localized on the border with euchromatin in the majority of chromosomes of Equus caballus and E. przewalskii. In contrast to chromosome 5 of E. caballus, acrocentric chromosomes of E. prezewalskii which are homologous to this chromosome have RE-CMA-blocks. We discuss a possible nature of the specific heterochromatin, which is insensitive to restriction enzyme digestion, and its role in the karyotype evolution.
Asunto(s)
Heterocromatina/ultraestructura , Caballos/genética , Metafase , Animales , Desoxirribonucleasa HpaII , Desoxirribonucleasas de Localización Especificada Tipo II , Hibridación Fluorescente in Situ , CariotipificaciónRESUMEN
Using nucleotide-specific agents Hoechst 33258, actinomycin D, chromomycin A3, and distamycin A, the Paris quadrifolia L. karyotype, and the location and nucleotide composition of heterochromatic bands were studied. The chromosome ideogram of H33258/AMD and CMA/DA heterochromatic bands was created by an image analysis system with the Videotest-Kario software. By fluorescence in situ hybridization, the 18S and 26S rRNA genes were mapped.
Asunto(s)
Mapeo Cromosómico , Heterocromatina/genética , Plantas/genética , ARN Ribosómico 18S/genética , ARN Ribosómico/genética , Bisbenzimidazol/química , Cromomicina A3/química , Dactinomicina/química , Distamicinas/química , Hibridación Fluorescente in Situ , Sondas ARNRESUMEN
The uniform distribution of satellite DNA II and IV has been revealed using in situ hybridization and differential staining in centromeric regions of autosomes. The sex chromosomes have not found such nucleotide blocks. There is only minor satellite IV block inside Y chromosome short arm. The Y chromosome has got some (TG)n enriched blocks distributed also among other parts of genome and one copy of sequences like human ZFY gene. The high repetitive fraction of bovine genomic DNA have not revealed RFLP. However, the difference has been found by blot hybridization between genomic organization of satellite IV in cattle and yak chromosomal DNA. Non-Mendelian distribution of some such nucleotide blocks has been obtained for interspecies crosses of cattle and yak.
Asunto(s)
Bovinos/genética , Cromosomas/ultraestructura , Variación Genética/genética , Genoma , Secuencias Repetitivas de Ácidos Nucleicos/genética , Animales , Bandeo Cromosómico , ADN Satélite/genética , Femenino , Hibridación in Situ , Masculino , Especificidad de la Especie , Cromosoma Y/ultraestructuraRESUMEN
The localization of the putative testis determining gene (TDF) was established with isotopic and nonisotopic methods of in situ hybridization in prometaphasic chromosomes of cattle. The results of both the methods were seen to coincide. The sites of hybridization have been revealed in X-chromosome (R-bands, q2.1 and q2.3.1). TDF was also localized in the proximal part of the long Y-chromosome arm.
Asunto(s)
Bovinos/genética , Mapeo Cromosómico , Genes/genética , Testículo/embriología , Cromosoma X/ultraestructura , Cromosoma Y/ultraestructura , Animales , Mapeo Cromosómico/métodos , ADN/genética , Sondas de ADN , Linfocitos/ultraestructura , Masculino , Metafase , Hibridación de Ácido Nucleico , TritioRESUMEN
Cytochemical and molecular peculiarities of heterochromatic regions of bovine chromosomes have been studied, using specific fluorochrome staining induced decondensation, in situ hybridization, pretreatment of restriction enzymes. The heterochromatin of autosomes demonstrated a strong homogeneity. In chromosome Y two small specific heterochromatic regions were found lacking a long repeated tandem block of nucleotides enriched in GC base pairs and having no tandem block of Bkm repeats (10(4) b.p.). This class repeats are probably interspersed in the bovine genome. A rather seldom character of mammalian karyotypes is the absence of cytochemical heterochromatin in the X chromosome.
Asunto(s)
Cromosomas/ultraestructura , Heterocromatina/ultraestructura , Mitosis , Animales , Azacitidina/farmacología , Composición de Base/efectos de los fármacos , Bovinos , Células Cultivadas/efectos de los fármacos , Células Cultivadas/metabolismo , Células Cultivadas/ultraestructura , Bandeo Cromosómico/métodos , Cromosomas/efectos de los fármacos , Cromosomas/metabolismo , Enzimas de Restricción del ADN/farmacología , ADN Satélite/efectos de los fármacos , Heterocromatina/efectos de los fármacos , Heterocromatina/metabolismo , Histocitoquímica , Linfocitos/efectos de los fármacos , Linfocitos/metabolismo , Linfocitos/ultraestructura , Mitosis/efectos de los fármacos , Hibridación de Ácido Nucleico , Secuencias Repetitivas de Ácidos Nucleicos/efectos de los fármacos , Cromosoma X/efectos de los fármacos , Cromosoma X/metabolismo , Cromosoma X/ultraestructura , Cromosoma Y/efectos de los fármacos , Cromosoma Y/metabolismo , Cromosoma Y/ultraestructuraRESUMEN
Using the decondensing effect of ethidium bromide and replicative (RBA) staining a high resolution map of cattle chromosomes was produced. The extent and distribution pattern of R(G) blocks were estimated quantitatively. The data thus obtained are correlated with the results of cytogenetic mapping in other mammalian species and in man.