RESUMO
Silver-staining of nucleolar organizer regions (NORs) in somatic cells of Holstein cattle (Bos taurus) and European buffalo Murrah type (Bubalus bubalus) indicates that the NORs are located in the telomeres of chromosomes 2,3,4,11, and 29 of cattle and chromosomes 3,4,6,23, and 24 of buffalo. Chromosome identification was by Q-banding. Analysis of 326 metaphase cells showed a mean value of 7.7 +/- 1.2 for Ag-NORs with a range between 4 and 10 for cattle. In all of the cells examined, either one or both homologues of chromosome 29 showed telomeric silver staining for cattle. Meiotic preparations showed not more than 5 clusters of silver grains in the pachytene stage of cattle.
Assuntos
Búfalos/genética , Bovinos/genética , Nucléolo Celular , Genes , Proteínas Ribossômicas/genética , Animais , Mapeamento Cromossômico , Prata , Especificidade da Espécie , Coloração e RotulagemRESUMO
The distribution of constitutive heterochromatin and nucleolus organizer regions (NOR's) in somatic as well as in meiotic chromosomes of Bos taurus, Bos banteng, Bison bison, and their hybrids are analyzed. C-bands are present in the centromeric regions of every autosome. The X chromosome does not show a distinct C-band in the centromeric region, whereas the Y chromosome contains an appreciable amount of C-band material. In somatic metaphases, NOR's are present on the telomeric ends of five pairs of autosomes. During pachytene, five autosomal bivalents contain NOR's on their terminal ends. Meiotic preparations made from sterile bulls did not contain stages beyond the degenerating pachytene, which are C-banding, more frequently showed clustering of heterochromatin than did the pachytene stage in normal bulls.
Assuntos
Doenças dos Bovinos/genética , Bovinos/genética , Nucléolo Celular/ultraestrutura , Heterocromatina , Hibridização Genética , Infertilidade Masculina/veterinária , Animais , Células Cultivadas , Centrômero , Bandeamento Cromossômico , Feminino , Células Híbridas/ultraestrutura , Infertilidade Masculina/genética , Masculino , Meiose , Metáfase , Coloração e Rotulagem , Testículo/citologia , Testículo/ultraestruturaRESUMO
Features characteristic of the hereditary syndrome of testicular feminization (tfm) were observed in a 7-year-old Quarter Horse. The horse had female body habitus and male psychosexual behaviour. Gonads located in the abdomen were testes and the uterus and cervix were absent. The vagina was normal in depth but ended as a blind pocket. The sex chromosome composition of testicular fibroblast and leucocyte cultures was XY. Construction of a family pedigree revealed a pattern of hereditary transmission similar to that reported for tfm in other mammalian species.
