Nucleolar organizer regions, satellite associations and nucleoli of goat cells (Capra hircus)

Abstract. The Polish White Improved goat karyotype consists of 29 pairs of acrocentric autosomes, a large acrocentric X chromosome and a metacentric Y chromosome which is the smallest in the karyotype. Staining of chromosomes with AgNO,sub>3 solution has revealed active nucleolar organizer regions (NOR) in terminal parts of q arms of pair 2, 3, 4, 5, and 28 chromosomes. Out of the total of 100 analysed cells 736 active NORs have been found, on average 7.4±0.2 per cell. Active NORs were most frequently observed in pair 2, and 3 chromosomes, most rarely on pair 5 chromosomes. In all the analysed cells 141, satellite associations (SA) were observed, on average 1.4±0.2 per cell. SAs most often occurred in cells with seven active NORs, and least often in cells with three or four nucleolar organizer regions. Most frequently in SAs the presence of pair 2, 3 and 28 chromosomes was observed. On meiotic chromosomes staining with AgNO₃ solution revealed two nucleoli stained with different intensity. Both nucleoli in the cell were of similar size.