Multiple satellite deoxyribonucleic acids in the calf and their relation to the sex chromosomes

Four distinct nuclear satellite DNAs from calf (Bos taurus) were isolated and the physical properties of native, single-stranded and renatured duplex molecules of each of the four satellite DNAs were studied by buoyant density-gradient centrifugation. These DNAs were localized in the calf nucleus and on calf metaphase chromosomes by in situ hybridization. In all cases, the calf satellite DNAs are preferentially situated at the centromeres of the autosomes, whereas the X and Y sex chromosomes contain little or none of the satellite DNAs. C-banding techniques showed constitutive heterochromatin at the centromeres of all the autosomes, but not on the X and Y chromosomes. Calf satellite 1 DNA (p = 1.716 g/ml) is at the centromeres of all of the autosomes. Although calf satellite II DNA (p = 1.722 g/ml) is the most widely dispersed over the karyotype, two-thirds of the grains were over the autosomal centromeres. Calf satellites III (p = 1.706 g/ml) and IV (p = 1.709 g/ml) are localized at the centromeres of most, but not all, of the autosomes. The four satellite DNAs each showed a strongly clumped distribution in interphase nuclei of both confluent and growing calf kidney cells in vitro.