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ADP-Ribosylation factors (ARFs) are ubiquitous approximately 20-kDa guanine nucleotide-binding proteins that stimulate cholera toxin-catalyzed ADP-ribosylation in vitro. Because the functional role(s) of ARF in mammalian systems is (are) elusive, we looked for ARF in Drosophila melanogaster, and report the partial purification and molecular cloning of an ARF from Drosophila. We cloned the Drosophila ARF 1 gene without library screening by a combination of 5 polymerase chain reactions (PCRs), yielding a 546-base open reading frame encoding 182 amino acids, which are > 93% identical to those of mammalian class I ARFs. This ARF gene maps to 79F3-6 in the proximal region of the left arm of Drosophila chromosome 3. The Drosophila ARF1 gene structure, including placement of introns, is highly conserved relative to mammalian class 1 ARF genes. A single ARF mRNA species of 1.8 kb was abundant in all Drosophila body segments. Recombinant Drosophila ARF 1 synthesized in Escherichia coli had biochemical and immunochemical activities similar to those of mammalian ARF. The similarities of sequence and biochemical properties between Drosophila and mammalian ARFs contrast with their differences from Drosophila arl (ARF-like protein), which does not stimulate cholera toxin-catalyzed ADP-ribosylation, and is only approximately 52-56% identical in amino acid sequence to mammalian ARFs.

The mapping of genes that control traits of economic importance will ultimately lead to the unravelling of the molecular basis of genetic variation. The main prerequisite for mapping of the unknown genes is a sufficient number of highly polymorphic marker loci which are evenly distributed along the chromosomes. The establishment of such a marker map in cattle and other species is based on methods used in human gene mapping. Comparative mapping facilitates saturation of the chromosomes with markers by utilizing the high degree of conservation of synteny among mammalian species. Comparative mapping will also allow access to the detailed mapping data and to extensive sequence information expected from the human genome initiative.

The gene encoding the porcine growth hormone (GH) has been localized to the q-arm of chromosome 12 using high-resolution R-banded chromosomes for in situ hybridization. We report here the localization of GH on the p-arm of this chromosome when using in situ hybridization on high-resolution G-banded chromosomes. Sequential Q- and R-banding show that this discrepancy is caused by a reversed orientation of chromosome 12 in the R-banded high-resolution karyotype published by Rønne et al. (1987) and the G-banded standard karyotype.

In situ hybridization analyses were conducted on porcine metaphase chromosomes using porcine liver albumin (ALB) and transferrin (TF) cDNA probes. The ALB gene was assigned to the q12 band of chromosome 8 and the TF gene to the q31 band of chromosome 13. For the latter, a statistically significant secondary peak was observed on the 6p15 band. However, the TF probe predominantly hybridized to the 13q31 band, indicating that this band is the most likely site of the TF gene. Since the TF gene belongs to linkage group V, this linkage group can now be assigned to chromosome 13. The TF and ALB probes were also used for restriction fragment length polymorphism (RFLP) analysis. A screening of 10 unrelated animals revealed TaqI RFLPs for both ALB and TF. Family studies indicated that the ALB and TF polymorphisms were controlled by three and two alleles, respectively.

A partial plasmid library with bovine genomic inserts of about 500 basepairs was screened with a (dC-dA)n.(dG-dT)n oligonucleotide probe for the repeated nucleotide motif (CA)n. Eleven positive clones (0.3% of all colonies screened) were discovered and were subsequently isolated and sequenced. Eight microsatellite loci were analysed, one with eight alleles, one with seven alleles, three with six alleles, one with three alleles and two with two alleles. Six of these microsatellites were mapped by PCR-analysis of a panel of somatic hybrid lines.

Specimens from three species of the Callicebus moloch group--C. moloch (N = 80), C. brunneus (N = 166), and C. cupreus (N = 23)--were studied. Twenty genetic loci were investigated through electrophoresis, genetic distances were estimated, and the results compared with the available cytogenetic data. Low values of genetic distance were encountered, contrasting with relatively large chromosome differences. We propose that recent karyotypic rearrangements, rather than other Pleistocene events, were the major evolutionary mechanisms determining speciation in these three taxa.

A congenic strain of mice with amyloidogenic apolipoprotein A-II (Apoa2c) on the genetic background of the amyloidosis-resistant SAM-R/1 strain was produced by 12 generations of backcrossing. Genome mapping using endogenous murine leukemia proviral markers was done in the congenic strain, termed R1.P1-Apoa2c. We confirmed that only a small region surrounding the apoA-II gene on chromosome 1 was transferred from the genome of the donor SAM-P/1 strain. The level and particle size of plasma high density lipoprotein were decreased in R1.P1-Apoa2c mice compared to those in the progenitor SAM-R/1 mice. The function of apoA-II can be studied using this strain of mice.

Brains affected by the progressive neurological disease bovine spongiform encephalopathy (BSE) contain scrapie-associated fibrils and the protease-resistant isoform of prion protein. The gene encoding the normal host prion protein (PRNP) has been mapped to human chromosome 20 and mouse chromosome 2 with the hamster cDNA probe pEA974. Using this probe and a panel of bovine-rodent hybrid somatic cells, we have mapped PRNP to bovine syntenic group U11 (100% concordancy). PRNP restriction fragment length polymorphisms (RFLPs) were detected with five of six enzymes (BglII, EcoRI, HindIII, MspI and TaqI) in sheep, in contrast to one of 16 enzymes (HincII) in cattle. Codominant segregation of the bovine HincII RFLP was demonstrated in six backcross pedigrees. While PRNP RFLPs are tightly linked to scrapie incubation period, and consequently susceptibility or resistance to disease in rodents and sheep, the relationship between the PRNP RFLPs and BSE incubation period has not been determined.

Ceruloplasmin (CP) is a copper-binding protein in vertebrate plasma. In the present study, the porcine ceruloplasmin gene was localized to the 13q32-q33 bands by in situ hybridization, using a human CP cDNA probe. This confirmed the localization of the porcine linkage group V to chromosome 13. The CP locus is closely linked to the transferrin locus in pigs. Their relative physical order on chromosome 13 is discussed. Comparisons are made with the order of these two loci in other mammalian species.

A polymorphism of the central part of chromosome 1 has been described from natural populations of the house mouse (Mus musculus). The region shows up as a C band-positive homogeneously staining region (HSR) under the light microscope. M. m. domesticus mice carry single band HSRs, whereas M. m. musculus animals have double band HSRs. HSR size variations have been described in both subspecies. The frequency of the HSR chromosome 1 in populations varies from 4% to 81%, but none of the large samples examined consisted only of homozygotes. In the subspecies M. m. domesticus, HSRs were found in North Africa and Western Europe, mainly in the hilly regions of Southern Germany and Switzerland. Localities with double HSRs are distributed all over the area of M. m. musculus. Based on the population data presented and DNA similarity of different HSRs, the origin and distribution of HSR chromosomes in the house mouse are discussed.

A approximately 700 bp bovine IFNG cDNA probe was used for the chromosomal localization of the IFNG gene in cattle using in situ hybridization technique. This locus has previously been assigned to chromosome 5 by analysis of a somatic cell hybrid panel. The in situ hybridization results obtained in the present study allow us to map the locus at the 5q22-q24 bands. Relative location of the IFNG gene and the class II cytokeratin and HOX3 gene clusters in cattle and humans is discussed.

Two genes coding for Na+,K(+)-ATPase alpha and beta subunits are localized on pig chromosome 4, to the q1.6-->q2.3 and 1.3-->q2.1 regions, respectively, by radioactive in situ hybridization. According to nucleotide and amino acid sequence comparisons with different human isoforms of Na+,K(+)-ATPase, these pig alpha beta ATPase genes show strong homologies with human alpha 1 and beta subunit ATPase genes, respectively. These results are discussed with respect to comparative mapping data of conserved genes in mammalian species. We showed that the pig cDNA probes encoding ATPase alpha and beta genes reveal DNA polymorphism in Meishan and Large White pigs.

A bovine XY female in Holstein-Friesian heifer, which appeared as female with uterus and ovaries but did not show the estrus until 23 months old after the birth, was cytogenetically and molecularbiologically examined. As results of chromosome analysis, leucocyte and fibroblasts from skin, spleen and kidney examined had only metaphase plates with 60, XY. From these results and the clinical characteristics, this case was clearly diagnosed as a pure XY female. It was ascertained that the two genes, ZFY and AMG gene which located on the short arm of the Y chromosome (Yp) were detected in normal bulls and a XY female, but were not detected in normal cow, mother cow and half-sib heifer by Southern blotting.

Using rat hormone sensitive lipase (LIPE) and human insulin receptor (INSR) cDNA probes, the LIPE gene was assigned to chromosome 6p11-q21 and the INSR gene to chromosome 2q11-q21 in pigs by in situ hybridization. In humans, these two genes are located on the q and p arms of chromosome 19, respectively. The present results provide the first in situ hybridization mapping data for porcine chromosome 2.

By the use of in situ hybridization, the bovine immunoglobulin gamma heavy chain (IGHG) gene was assigned to chromosome 21q24. Fifteen percent of the total grains were scored on chromosome 21, with about 65 percent of these grains located on the q24 band. The present results confirm a previous synteny study and provide the precise chromosomal localization of this gene in the cattle genome.

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.

We mapped the beta-globin gene cluster of the goat (Capra hircus) to a specific chromosomal region of the species, using in situ hybridization. The probe we used was a 1.2-kb Eco RI/Bam HI genomic DNA fragment that was 3H labeled to high specific activity by the random primer method. This DNA fragment contains part of the 5' flanking region and the first two exons of the epsilon IV gene of the goal beta-globin gene cluster. Our results show that this gene cluster is on chromosome 7 in the region of bands 33 to 35 based on BrdU G-banded chromosome preparations of this species.