Eleven probes were assigned to bovine chromosomes 1 to 7 by fluorescence in situ hybridization (FISH). The identification of chromosomes was based on QFQ-banding prior to in situ hybridization and comparison with the Reading Conference (1976) and ISCNDA (1989) standards. The probes used for FISH can now be utilized as identification and discrimination features for bovine chromosomes 1 to 7 and particularly for chromosomes 4 and 6, which are difficult to distinguish. Comparison of our mapping data with previous assignments and of the standard chromosome banding patterns prompt us to propose a change in the ISCNDA nomenclature: ISCNDA chromosome 4 should be named chromosome 6 and vice versa. Chromosome 4 is marked by the ribosomal RNA cluster RNR3, and chromosome 6 is characterized by the casein gene cluster and an anonymous satellite (D6Z1).

Animals↗

PubMed1994

Distribution and hybridization patterns of the insertion element IS900 in clinical isolates of Mycobacterium paratuberculosis.

Reference strains and 31 clinical isolates of M. paratuberculosis, mainly from goats, were analysed for restriction fragment length polymorphism (RFLP). Restriction digests of bacterial DNA were hybridized with a repetitive insertion sequence, IS900, to obtain banding patterns for comparison of strains. Twenty-five of the 31 field-strains hybridized with IS900, and five hybridization patterns were identified. It was not possible to identify specific patterns for goat strains of M. paratuberculosis. Four hybridization patterns were similar, whereas the fifth pattern of a sheep strain diverged considerably in position and number of bands. Six goat strains failed to hybridize with IS900, and the absence of IS900 was verified by the polymerase chain reaction and hybridization with an oligonucleotide probe. The six IS900-negative goat strains had diverging phenotypic properties, and the identification of these strains is discussed. The present study shows that M. paratuberculosis strains infecting goats are genetically similar to cattle strains and that IS900 is a specific genetic element for identification of M. paratuberculosis.

Animals↗

PubMed1994

A study of variability in the MHC class II beta 1 and class I alpha 2 domain exons of Atlantic salmon, Salmo salar L.

Variability in the most extracellular exons of Atlantic salmon MHC-Sasa class I and class II was studied by polymerase chain reaction (PCR) amplification followed by sequencing. The domains studied were class I alpha 2 and class II beta 1. The material used was genomic DNA of fish, mainly derived from the major Norwegian breeding pool, supplemented with some material from a minor breeder and a local river strain. The analysis revealed extensive variation, most individuals being heterozygous with at least two variants.

Amino Acid Sequence↗

PubMed1994

Assignment of bovine synteny groups U27 and U8 to R-banded chromosome 12 and 27, respectively.

Two microsatellite-containing cosmids, clOBT361 and clOBT355 were localized to bovine R-banded chromosome 12 and 27, respectively, by fluorescence in situ hybridization. The two microsatellites were subcloned from the cosmids and named INRA209 and INRA206, respectively. Primers were designed from the sequence information and used for PCR amplification with a panel of 36 previously characterized hamster/bovine somatic cell hybrids. This allowed the assignment of the two microsatellites to bovine synteny groups U27 and U8, respectively. The result permits the conclusion that bovine synteny U27 corresponds to BTA12 and that bovine synteny group U8 corresponds to BTA27, reducing to five the number of unassigned bovine synteny groups. Furthermore, as a high level of polymorphism was revealed by the two microsatellites, they have all the required characteristics for good genetic map markers.

Animals↗

PubMed1994

Isolation and sequence determination of porcine class II DRB alleles amplified by PCR.

The first domain exon of a porcine DRB gene was amplified by the polymerase chain reaction (PCR), and the nucleotide sequence was determined. In a material consisting of 10 unrelated animals, five different alleles were identified, all probably belonging to a single locus designated DRB1. In addition, a non-expressed locus, designated DRB2, was coamplified with DRB1. This pseudogene, containing a single base deletion, also exhibited some variation, but at a very restricted level compared with DRB1. In pairwise comparisons of DRB1 alleles, the number of amino acid substitutions ranged between 6 and 21 out of 83 positions compared.

Alleles↗