Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Nucleolus organizer regions, types of association and identification of carrier chromosomes in domestic sheep | Genet Sei Evol 1990 22 273-277 Elsevier INRA 273 Original article Nucleolus organizer regions types of association and identification of carrier chromosomes in domestic sheep M Moreno-Millán A Rodero-Franganillo Universidad de Córdoba Facultadde Veterinaria Departamento de Genética y Mejora Laboratorio de Citogenética 14005 Cordoba Spain Received 20 November 1989 accepted 15 May 1990 Summary - The frequency of chromosomes carrying nucleolus organizer regions NORpositive and the percentage of association between these chromosomes were determined in sheep metaphase spreads. The sequential R-NOR banding technique permitted identification of the chromosome regions involved as the telomeric ends of chromosomes 1 lp 2 2q 3 2q 4 and 25. nucleolus organizer regions sequential R-NOR banding sheep Resume - Regions de 1 organisateur nucléolaire types d associations et d identification des chromosomes porteurs chez le mouton. La Ịréquence de chromosomes porteurs de ỉa région organisation nucleolaire NOR et le pourcentage d association entre chromosomes NOR-positifs ont été étudiés chez le mouton. La méthode de marquage séquentiel R-NOR a permis d identifier comme regions chromosomiques impliquées les télomères des chromosomes 1 Ip 2 2q 3 3q 4 et 25. regions de 1 organisateur nucléolaire bandes séquentielles R-NOR mouton INTRODUCTION The silver-staining technique developed by Goodpasture and Bloom 1975 permitted the differential staining of chromosome proteins from particular regions of the chromosome the nucleolus organizer regions. Miller et al 1976 showed that only the active NORs were stained with silver in human-mouse somatic cell hybrids. In domestic sheep the NORs are located in the telomeric regions of 5 pairs of chromosomes. In this paper the frequency distribution of these chromosomes is determined and the NOR-carrier chromosomes are identified using the R-NOR sequential banding technique. Correspondence and reprints 274 M Moreno-Millán A Rodero-Franganillo MATERIALS
