Chromosome mapping in cattle using mouse myeloma/calf lymph node cell hybridomas

First steps: bovine genomics in historical perspective

The vision of Morris Soller was instrumental in launching the field of bovine genomics. This study is a review of the early years of bovine gene mapping leading up to the sequencing and assembly of the bovine genome in 2009. A historical perspective of parasexual, linkage and physical mapping is provided with a focus on the contribution of these maps to the eventual assignment and orientation of genes and sequence to cattle chromosomes.

Tentative chromosomal localization of the bovine major histocompatibility complex by in situ hybridization

A genetic region, most likely the major histocompatibility complex, was assigned to bands q13-23 of cattle chromosome 23 by in situ hybridization using a cloned DNA sequence of a class I gene of the pig major histocompatibility complex.

The bovine gene map

The present status of the bovine gene map as well as some of the methods and strategies important for future efforts in completing the gene map of cattle are reviewed.

Veterinary sources of nonrodent monoclonal antibodies: interspecific and intraspecific hybridomas

The generation of monoclonal antibodies from species other than rats and mice has developed slowly over the last 20 years. The advent of antibody engineering and realization of the advantages of nonmurine antibodies, in terms of their superior affinities and specificities, and their potential as components of human and veterinary therapeutics has increased their relevance recently. There have been significant advances in the development of myeloma and heteromyeloma fusion partners. This is an opportune moment to consolidate experiences of MAb production across the range of species of veterinary interest and place it into context with other developments in the field of monoclonal antibodies. The background to the development of antibodies from species other than the mouse is discussed. The species and antigens used to date are reviewed, as are the methods and results reported. A suggested protocol is provided for first attempts to exploit the huge potential of this aspect of hybridoma technology and suggestions are made for its further expansion.

Anchored reference loci for comparative genome mapping in mammals

Recent advances in gene mapping technologies have led to increased emphasis in developing representative genetic maps for several species, particularly domestic plants and animals. These maps are being compiled with two distinct goals: to provide a resource for genetic analysis, and to help dissect the evolution of genome organization by comparing linkage relationships of homologous genes. We propose here a list of 321 reference anchor loci suitable for comparative gene mapping in mammals and other vertebrate classes. We selected cloned mouse and human functional genes spaced an average of 5-10 centiMorgans throughout their respective genomes. We also attempted to include loci that are evolutionarily conserved and represented in comparative gene maps in other mammalian orders, particularly cattle and the domestic cat. We believe that the map may provide the basis for a unified approach to comparative analysis of mammalian species genomes.

Confirmation of assignment of the bovine K-casein locus by PCR

The provision of a bovine gene map will allow the ready identification of genetic disease in cattle and will lead to the identification of the genetic loci responsible for quantitative traits of economic importance. An extension of the polymerase chain reaction to the identification of linkage in bovine-Chinese hamster cell hybrids has improved the speed and facility of the assignment of genes to linkage groups and thus makes it easier to achieve a bovine linkage map.

Goat-mouse hybridomas secreting goat immunoglobulins

Monoclonal antibodies specific for an allotypic marker of goat IgG2 were used to select goat-mouse hybrid cells secreting goat IgG2. Four of these hybrid cell clones continued to synthesize goat IgG2 (5-15 micrograms/ml) for over eight months. They will be used to study goat IgG gene regulation.

Molecular cytogenetics of cattle: a genomic approach to disease resistance and productivity

Classical cytogenetics has been merged with somatic cell and molecular genetics to facilitate mapping of the bovine genome. A physical map is presently being generated by the use of hybrid somatic cells and in situ hybridization to assign genes to chromosomes. A complementary genetic map is being generated by analysis of recombination of polymorphic loci, many of them identified with the same cloned DNA probes used for physical mapping. The eventual utilization of this map for selective breeding of disease resistance and productivity is dependent on the saturation of the map with polymorphic markers at a density that will assure linkage of genes influencing desirable phenotypes with at least one polymorphic marker. The identification of regions of chromosomal conservation among cattle, mice, and humans is being exploited to facilitate the saturation of the bovine map with useful markers.

Mapping of bovine PRGS and PAIS genes in hybrid somatic cells: syntenic conservation with human chromosome 21

Somatic cell genetics coupled with enzyme electrophoresis has facilitated the mapping of PRGS and PAIS genes in cattle. Individual cow-hamster hybrid cell lines established by fusion of mutant CHO cells, ade-C and ade-G, with cattle leukocytes required complementing bovine genes for PRGS and PAIS, respectively, when propogated on selective media. Homogenates of 12 PRGS+ hybrid clones and 12 PAIS+ hybrid clones retained the bovine electromorph of SOD1 while extensively segregating 14 biochemical markers of other cattle syntenic groups. Secondary cattle-hamster hybrid subclones which segregated bovine PRGS and PAIS in late passages on nonselective media concordantly segregated bovine SOD1. These data support a syntenic relationship among PRGS, PAIS, and SOD1 on cattle syntenic group U10. An interferon receptor locus, IFREC, is also syntenic with SOD1. This synteny represents an extensive conservation of bovine U10 and the "Down syndrome region" of human chromosome 21.

Peptidases A, B, C, D and S in the American mink: polymorphism and chromosome localization

An electrophoretic analysis of peptidases was carried out in a population of American mink. Based on substrate and tissue specificities, as well as subunit composition, homologies were established between mink peptidases A, B, C, D and S and human peptidases. Polymorphism for peptidases B and D was demonstrated for minks of three coat colour types. Breeding data indicated that the peptidase variations are under the control of allele pairs at distinct autosomal loci designated as PEPB and PEPD, respectively. Using a panel of American mink-Chinese hamster hybrid clones, the gene for PEPB was assigned to mink chromosome 9.