Comparative chromosome painting between the domestic pig (Sus scrofa) and two species of peccary, the collared peccary (Tayassu tajacu) and the white-lipped peccary (T. pecari): a phylogenetic perspective.

The Suidae and the Dicotylidae (or Tayassuidae) are related mammalian families, both belonging to the artiodactyl suborder Suiformes, which diverged more than 37 million years ago. Cross-species chromosome painting was performed between the domestic pig (Sus scrofa; 2n = 38), a representative of the Suidae, and two species of the Dicotylidae: the collared peccary (Tayassu tajacu; 2n = 30) and the white-lipped peccary (T. pecari; 2n = 26). G-banded metaphase chromosomes of the two peccaries were hybridized with whole chromosome painting probes derived from domestic pig chromosomes 1-18 and X. For both peccary species, a total of 31 autosomal segments that are conserved between pig and peccary could be identified. The painting results confirm conclusions inferred from G-band analyses that the karyotypes of the collared peccary and the white-lipped peccary are largely different. The karyotypic heterogeneity of the Dicotylidae contrasts with the relative homogeneity among the karyotypes of the Suidae. For this difference between the Dicotylidae and the Suidae, a number of explanations are being postulated: 1) the extant peccaries are phylogenetically less closely related than is usually assumed; 2) the peccary genome is less stable than the genome of the pigs; and 3) special (e.g. biogeographical or biosocial) circumstances have facilitated the fixation of chromosome rearrangements in ancestral dicotylid populations.

Notes on placentation in the Suina.

We examined the gross and microscopic anatomy of placental tissues and umbilical cords from six species representing the three living families of the Suina. These species included, of the Suidae, the wart hog (Phacochoerus aethiopicus), the giant forest hog (Hylochoerus meinertzhageni), the domestic pig (Sus scrofa), and the banded pig of Malaysia (Sus scrofa vittatus); of the Tayassuidae, the white-lipped peccary (Tayassu pecari); of the Hippopotamidae, the hippopotamus (Hippopotamus amphibius) and the pigmy hippopotamus (Choeropsis liberiensis). All these species have a diffuse epitheliochorial placenta. The chorion is folded, and has on its surface rows of shallow ripples or villi, interrupted by round, oval or irregularly shaped areolae. Placental capillaries indent the epithelial layer covering the tops and sides of the interareolar villi, but not the columnar cell layer lying in the troughs between these villi or covering the areolae. Cuboidal cells cover the crests of the villi in the Suidae and Hippopotamidae, whereas in the Tayassuidae the epithelium is syncytial in appearance. The similarities in placental structure between the six species are more apparent than the differences. Suidae and Tayassuidae have smooth umbilical cords containing two arteries and one vein; those of the Hippopotamidae are pustule-encrusted and contain two arteries and two veins.

Cytogenetic analysis of cell lines derived from metastases of a mammary carcinoma in a dog.

Three cell lines derived from two metastases of a mammary carcinoma in a female dog were analyzed cytogenetically. All three cell lines showed a modal chromosome number of 76, with ranges of 74-77, 72-78, and 73-78. A biarmed chromosome in addition to the X chromosomes was observed in all cells of one cell line, and in a part of the cells of the other two cell lines. Results of banding analyses indicated that this chromosome was identical in the three cell lines, and can thus be considered a clonal marker. Additional biarmed chromosomes have not been reported previously from mammary tumor cells, although their presence is rather common in other canine neoplasms.

Construction of a bovine-murine heteromyeloma cell line; production of bovine monoclonal antibodies against rotavirus and pregnant mare serum gonadotrophin.

Bovine-murine heteromyeloma cell lines were prepared by fusing lymphoid cells from a bovine leukemia virus (BLV)-infected cow with mouse myeloma cells. Selection of hybrid cell colonies was based on the ratio of bovine and murine chromosomes, the presence of cell-surface immunoglobulins and growth characteristics. First-generation fusion partners were compared for fusion efficiency and the number of antigen-specific antibody-producing clones generated. Hybrid cell colonies that initially secreted antibodies were selected from first-generation heteromyelomas to function as second-generation fusion partners. Although fusion efficiencies for both generations did not differ, the second-generation heteromyelomas yielded a higher number of specific antibody-producing clones. Fusion of hteromyelomas with either lymph node cells or splenocytes indicated that fusion with lymph node cells results in a higher number of specific antibody-producing clones, whereas fusion efficiency was found to be higher with splenocytes. The optimal time intervals between the final booster injection and fusion were found to be 4 days for splenocytes and 7 days for lymph node cells. Finally, the characterization of bovine monoclonal antibodies against bovine rotavirus and pregnant mare serum gonadotrophin and their neutralizing capacities in vitro are described.

Cultured pig rhabdomyosarcoma cells with a deletion of the Xq24-qter chromosome region: an immunochemical and cytogenetic characterization.

A pig rhabdomyosarcoma cell line (PRUM59) was established, and the immuno(histo)chemical and cytogenetic characterization of these cells was determined. At various swine farms in the Netherlands, pigs were observed that had solitary or multiple skin nodules, which were diagnosed as rhabdomyosarcomas. Cells of a tumor derived from a 3.5-week-old female pig were cultured for immunochemical and cytogenetic analyses. The cell line had characteristic features of undifferentiated muscle cells, similar to those observed in tumor tissue sections; they contained titin, a high-molecular weight protein specific for striated muscle, as dot-like aggregates and as filaments, desmin filaments and cross-striations, smooth muscle actin stress fibers, and vimentin filaments. The cells stained positively for striated muscle actin and tropomyosin as well. The immunohistochemical staining results were supported by results of immunoblotting experiments. Karyotyping of the cells revealed a deletion of a major part of Xq24-qter, a part of the long arm of 1 of the 2 X chromosomes. The other X chromosome and all autosomes appeared to be normal.

Chromosome studies in cattle with hereditary zinc deficiency (lethal trait A 46).

Summary Blood lymphocyte and skin fibroblast cultures from cattle with hereditary zinc deficiency (lethal trait A 46) have not revealed unusually large numbers of cells with chromosomal aberrations as reported by Herzog and Höhn (6).

Sister chromatid exchanges in calves with hereditary zinc deficiency (lethal trait A 46).

Frequencies of sister chromatid exchanges (SCEs) in cultured blood lymphocytes are rather lower than higher in calves with hereditary zinc deficiency (lethal trait A 46) than in healthy, normal cows.

[Chromosome studies of 300 young Dutch-Friesian and Holstein-Friesian bulls intended for use in artificial insemination]. / Chromosoomonderzoek aan 300 jonge Fries-Hollandse en Holstein-Friesian stieren bestemd voor KI-gebruik.

Three hundred young Dutch Friesian and Holstein-Friesian bulls, kept in the Central Opfokstation (Central Breeding Station) in Terwispel (Friesland), were studied cytogenetically, using conventional staining methods. Structural chromosome aberrations were not observed. Four animals showed XX/XY-chimerism in the lymphocytes, probably caused by the interchange of haemopoietic cells between the male and its female co-twin by placental vascular anastomosis. The number of (iso)chromatid gaps in 25 metaphase plates varied from 0 to 4. Chromosome breaks were not observed. The chimeric bulls and those with (iso)chromatid gaps were not found to show significantly reduced fertility rates.

Comparative study of pig-rodent somatic cell hybrids.

The pig chromosome complement of six different types of pig-rodent hybrid cell lines was examined by means of fluorescence in situ hybridization with a porcine SINE probe. The cell lines were obtained by fusing pig lymphocytes with cells of the Chinese hamster cell lines wg3h, BK14-150 and E36, and of the mouse cell lines NSO, PU and LMTK-. The hybrids were analysed with respect to: (1) the number of pig chromosomes, (2) the type of pig chromosomes, (3) the occurrence of pig-rodent chromosome translocations, and (4) the presence of pig chromosome fragments. The results show that the number of pig chromosomes varied within and among hybrid cell lines. The pig-hamster hybrids mainly retained nontelocentric pig chromosomes, whereas the pig-mouse hybrids also retained telocentric pig chromosomes. Pig-rodent chromosome translocations were found in all types of hybrids, but the incidence was in general low. Chromosome fragments were abundant in BK14-150 hybrids, and rare in most other hybrid cell lines. It is concluded that the SINE probe is a useful tool to make a preliminary characterization of the porcine chromosome complement of pig-rodent somatic cell hybrids. The results of this characterization can be used to select hybrids for further cytogenetic analysis. Furthermore, our data show that different rodent cell lines will have to be used as fusion partners for the production of hybrids when constructing a panel informative for all pig chromosomes.

Numerical variation of nucleolar organizer regions after silver staining in domestic and wild Suidae (Mammalia).

Selective silver staining was used to investigate the cellular distribution of numbers of nucleolar organizer regions (NORs) in domestic pigs (Sus scrofa) of eight different breeds, the European wild boar (S. scrofa scrofa), Indonesian wild boar (S. scrofa vittatus), Javan warty pig (S. verrucosus), Sulawesi warty pig (S. celebensis), and pigmy hog (S. salvanius). In the domestic pig as well as in the wild (sub)species of Sus, actively transcribing ribosomal RNA genes were found to be present in the secondary constrictions of chromosome pairs 10 and 8. Chromosomes 10 were consistently Ag-positive. Chromosomes 8 less frequently showed Ag-NORs, resulting in different mean numbers of Ag-NORs per individual animal. Mean Ag-NOR numbers per breed or (sub)species were generally higher in the wild representatives of Sus than in the domestic breeds. The highest mean numbers of Ag-NORs were observed in the Meishan breed and in S. celebensis and S. salvanius. The Meishan breed appears to be conservative in Ag-NOR staining pattern, being more comparable to the Asian wild Suidae than to the European breeds.

Comparative cytogenetic studies in Sus verrucosus, Sus celebensis and Sus scrofa vittatus (Suidae, Mammalia).

Chromosome studies on the Javan warty pig (Sus verrucosus), the Sulawesi warty pig (S. celebensis) and a subspecies of the wild boar, S. scrofa vittatus, have revealed diploid chromosome numbers of 38. The morphology and C-band size of chromosome 10 are different in S. verrucosus and the two other species. Both S. verrucosus and S. celebensis have a Y chromosome that is larger than the Y chromosome of domestic and wild S. scrofa, and is submetacentric rather than metacentric. There are differences between all three species in the G-banding pattern of the long arm of the Y chromosome. The presence of 2n = 38 chromosomes in the Javan warty pig and the Sulawesi warty pig provides new strong evidence that the basic chromosome number in the genus Sus is 38. The differences in karyotype between these pigs (chromosome 10 and the Y chromosome) confirm that they are separate species.

The porcine PGD gene is preferentially lost from chromosome 6 in pig x rodent somatic cell hybrids.

The 6-phosphogluconate dehydrogenase (PGD) and glucose phosphate isomerase (GPI) genes are both located on chromosome 6 in the pig (Sus scrofa domestica). Nonetheless, the PGD gene was absent in a total of 17 GPI-positive cell lines found in three independently derived panels of pig x rodent somatic cell hybrids. In most of these cell lines we found an apparently normal pig chromosome 6 at cytogenetic analysis. These results suggest instability of the porcine PGD gene region in interspecies hybrid cells.

Chromosome homology between the domestic pig and the babirusa (family Suidae) elucidated with the use of porcine painting probes.

Homology among three pairs of domestic pig (Sus scrofa) and five pairs of babirusa (Babyrousa babyrussa) autosomes has been demonstrated with the use of porcine painting probes. With the results of this study, in addition to data obtained earlier through the application of banding techniques, correspondence between all individual chromosomes of these two distantly related pigs has been identified.

Variation in size of Ag-NORs and fluorescent rDNA in situ hybridization signals in six breeds of domestic pig.

Variation of the size of silver-stained nucleolar organizer regions (NORs) of chromosomes 10 and 8 was studied in pigs of six breeds (Sus scrofa L.). The silver deposits were quantified by image analysis and the results were normalized for each Ag-NOR chromosome. In general, normalized values for chromosomes 10 were higher than those for chromosomes 8, suggesting that the NOR activity of chromosomes 10 is dominant as compared to that of chromosomes 8. However, high values for chromosomes 8 were found in the Meishan breed and in some Piétrain pigs, indicating a high transcriptional activity of the rRNA genes on these chromosomes. In some pigs, the relative quantities of rDNA in chromosomes 10 and 8 were investigated by fluorescent in situ hybridization and the results were compared with those of the silver staining procedure. It is concluded that Ag-NOR sizes on chromosomes 10 are relatively well correlated to the number of rRNA genes, whereas the absence or the small size of Ag-NORs on chromosomes 8, often observed in pigs, is the result of low NOR activity rather than of absence of rDNA.

Localization of 18S + 28S and 5S ribosomal RNA genes in the dog by fluorescence in situ hybridization.

The gene clusters encoding 18S + 28S and 5S rRNA in the dog (Canis familiaris) have been localized by using GTG-banding and fluorescence in situ hybridization. The 18S + 28S rDNA maps to chromosome regions 7q2.5-->q2.7, 17q1.7, qter of a medium-sized, not yet numbered autosome, and Yq1.2-->q1.3. Our data show that there is one cluster of 5S rDNA in the dog, which maps to chromosome region 4q1.4.

Localization of the 18S, 5.8S and 28S rRNA genes and the 5S rRNA genes in the babirusa and the white-lipped peccary.

The locations of the genes encoding 18S, 5.8S and 28S rRNA and 5S rRNA were studied in two relatives of the domestic pig, the babirusa (Babyrousa babyrussa) and the white-lipped peccary (Tayassu pecari). In the babirusa, the 18S, 5.8S and 28S rDNA is located on chromosomes 6, 8 and 10. The genes on chromosomes 8 and 10 are actively transcribed, in contrast to those on chromosomes 6. In the white-lipped peccary, this rDNA was found to be located on chromosomes 4 and 8. The genes on both of these pairs of chromosomes are actively transcribed. The 5S rDNA was physically mapped to chromosome 16 in the babirusa, and to chromosome 11 in the white-lipped peccary. These data are compared to similar data obtained for the domestic pig, and confirm previously recognized chromosome homologies.

Construction of a cytogenetically characterized porcine somatic cell hybrid panel and its use as a mapping tool.

A new panel of cytogenetically characterized pig-rodent somatic cell hybrids was constructed and tested for twelve microsatellite markers with PCR. Cytogenetic characterization of hybrids was accomplished by fluorescence painting and GTG-banding of metaphase chromosomes. The panel consists of 15 independent pig-hamster and 6 independent pig-mouse cell lines. In the panel, all pig autosomes and the X Chromosome (Chr) are represented, and it is informative for all chromosome pairs except 2-14, 2-15, 3-9, 14-15, 14-16, and 16-17. The microsatellites tested were S0022, S0023, S0084, S0098, S0112, S0113, S0114, S0115, S0117, S0118, S0119, and S0120. The PCR results obtained in the 21 hybrids were compared with the cytogenetic data and analyzed for concordancy and correlation. Eight microsatellites could be assigned to specific pig chromosomes, confirming seven assignments based on linkage analysis.

Mapping of the Na+, K(+)-ATPase subunit alpha 2 (ATP1A2) and muscle phosphofructokinase (PFKM) genes in pig by somatic cell hybrid analysis.

Two expressed sequence tags were isolated from a porcine skeletal muscle cDNA library and identified as the putative partial cDNAs of the porcine Na+, K(+)-ATPase subunit alpha 2 (ATP1A2) and muscle phosphofructokinase (PFKM) genes after sequencing and homology search. Results of analysis of a pig-rodent somatic cell hybrid panel by PCR allowed the assignments of ATP1A2 to porcine chromosome (chr) 4 and of PFKM to porcine chr 5. These assignments support previously observed conservation of syntenic relationships between human chr 1 and porcine chr 4 and between human chr 12 and porcine chr 5.