F. Gu

The PiGMaP consortium cytogenetic map of the domestic pig (Sus scrofa domestica)

llNRA, Laboratoire de Grnrtique Cellulaire, BP27, 31326 Castanet-Tolosan, France 2Department of Functional Morphology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands 3Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden 4Division of Anatomy, Department of Anatomy and Physiology, The Royal Veterinary and Agricultural University, Copenhagen, Denmark 5Division of Animal Genetics, Department of Animal Science and Animal Health, The Royal Veterinary and Agricultural University, Copenhagen, Denmark 6Department of Clinical Genetics, University of Ulm, Ulm, Germany 7Laboratoire de Cytomrtrie, CEA, Fontenay-aux Roses, France

cDNA sequence and chromosome localization of pig {alpha}1,3 galactosyltransferase

Human serum contains natural antibodies (NAb), which can bind to endothelial cell surface antigens of other mammals. This is believed to be the major initiating event in the process of hyperacute rejection of pig to primate xenografts. Recent work has implicated galoctosyl α1,3 galactosyl β1,4 N-acetyl-glucosaminyl carbohydrate epitopes, on the surface of pig endothelial cells as a major target of human natural antibodies. This epitope is made by a specific galactosyltransferase (α1,3 GT) present in pigs but not in higher primates. We have now cloned and sequenced a full-length pig α1,3 GT cDNA. The predicted 371 amino acid protein sequence shares 85% and 76% identity with previously characterized cattle and mouse α1,3 GT protein sequences, respectively. By using fluorescence and isotopic in situ hybridization, the GGTA1 gene was mapped to the region q2.10–q2.11 of pig chromosome 1, providing further evidence of homology between the subterminal region of pig chromosome 1q and human chromosome 9q, which harbors the locus encoding the AB0 blood group system, as well as a human pseudogene homologous to the pig GGTA1 gene.

Mapping of the porcine lipoprotein lipase (LPL) gene to chromosome 14q12→q14 by in situ hybridization

Using a porcine lipoprotein lipase (LPL) cDNA probe, the LPL gene was assigned to the q12→q14 bands of chromosome 14 in pigs by in situ hybridization.

Localization of the IGHG, PRKACB, and TNP2 genes in pigs by in situ hybridization

The porcine genes encoding the immunoglobulin gamma heavy chain (IGHG), cAMP-dependent protein kinase catalytic beta subunit (PRKACB), and transition protein 2 (TNP2) were mapped to Chromosomes (Chrs) 7 q25–q26, 6q31–q33, and 3p13-cent, respectively, by in situ hybridization. Localization of the IGHG gene confirms the assignment of linkage group III to Chr 7. Our results show that the IGHG locus in pigs, similar to the situation in other mammalian species, viz. humans, mouse, cattle, and river buffaloes, is located on the terminal region of the chromosome. The assignment of the PRKACB gene extends the homology observed between porcine Chr 6q and human Chr 1p. Mapping of the TNP2 gene provides the first marker assigned to the p arm of Chr 3 in pigs. The present study contributes to the development of the physical gene map in pigs and also bears significance in terms of comparative gene mapping.

Assignment of the linkage group EAM-TYRP2-TPP2 to chromosome 11 in pigs byin situ hybridization mapping of the TPP2 gene

Restriction fragment length polymorphisms are described for the genes coding for tripeptidyl peptidase II (TPP2) and tyrosinase related protein II (TYRP2) in pigs. A linkage group comprising these loci and the locus for blood group M (EAM) was established by two-point lod score analysis in a three-generation pedigree. Multipoint analysis indicated the linear order EAM-1.1-TYRP2-8.4-TPP2 (recombination distances are given as Kosambi cM). The linkage group was assigned to porcine chromosome 11—the first on this chromosome—throughin situ hybridization mapping of the TPP2 gene. TPP2 is the first gene localized on this chromosome usingin situ hybridization.

A panel of VNTR markers in pigs

By cloning tandemly repeated sequences from the pig genome by use of non-porcine minisatellite probes for library screening, five novel polymorphic VNTR loci were isolated: three minisatellites and two satellite-like loci. Four of them could be mapped onto chromosomes by linkage analysis and/or in situ hybridization. They were assigned to Chromosomes (Chrs) 5, 6, 14, and 16. Physical mapping on both presumed satellites and on one of the minisatellites revealed that the former resided near or at the centromere and the latter towards the chromosome ends. The location of the minisatellite is of particular interest since, together with data on three other minisatellites previously isolated, it supports the idea that, as in humans, minisatellites may preferentially be subtelomeric also in pigs.

A PSEUDOAUTOSOMAL MINISATELLITE IN THE PIG

A wide range of human minisatellite sequences isolated to date have been shown to be hypervariable and therefore extremely useful for individual identification, parentage testing, and linkage analysis and genome mapping [multi-locus DNA fingerprinting (Jeffreys 1987), and single-locus profiling (Nakamura et al. 1987)]. In addition, cross-hybridization screening of non-human genomic libraries with human probes has allowed polymorphic species-specific minisatellites to be developed in mice (Kelly et al. 1989), chicken (Bruford and Burke 1991), cattle (Georges et al. 1991), and pigs (Signer and Jeffreys 1993). Here we report a porcine minisatellite that was isolated from a genomic Charomid library and has been characterized by segregation analysis and in situ hybridization. Charomid libraries were produced as described by Armour and coworkers (1990) for the human genome. Briefly, DNA extracted from sperm or blood samples from six different pig breeds was pooled and digested to completion with MboI. For the production of genomic libraries enriched for highly variable tandem repeats (minisatellites), two size fractions from 4 to 7 kb and 7 to 20 kb were selected by two rounds of preparative agarose gel electrophoresis and cloned into Charomid vector 9-36 (Saito and Stark 1986). Twelve clones in the 4 to 7 kb library cross-hybridized to the human minisatellite probe 33.6 (Jeffreys et al. 1985). One of these isolates, pCMS12, produced complex DNA patterns derived from multiple polymorphic loci when hybridized to pig genomic Southern blots (Signer and Jeffreys 1993). By use of this clone to rescreen the libraries, a novel minisatellite cloned as a 4.8kb Sau3AI fragment was detected and termed porcine Charomid minisatellite 14 (pCMS14). pCMS14 hybridized simultaneously to several loci in pig DNA at intermediate and low stringency. Hybridization was therefore performed, including pig competitor DNA (5 gg/ml), and post-hybridization washings were