RESUMO
Upon substituting Ca for Eu in the local-moment ferromagnet EuB6, the Curie temperature T(C) decreases substantially with increasing dilution of the magnetic sublattice and is completely suppressed for x
Assuntos
Bovinos/genética , Fatores de Crescimento Neural/genética , Receptores Proteína Tirosina Quinases/genética , Receptores de Fator de Crescimento Neural/genética , Receptores de Neurotransmissores/genética , Animais , Sequência de Bases , Mapeamento Cromossômico/veterinária , Sequência Conservada , Cosmídeos/química , Marcadores Genéticos , Humanos , Hibridização in Situ Fluorescente/veterinária , Camundongos , Dados de Sequência Molecular , Fatores de Crescimento Neural/química , Receptores Proteína Tirosina Quinases/química , Receptor do Fator Neutrófico Ciliar , Receptores de Fator de Crescimento Neural/química , Receptores de Neurotransmissores/química , Análise de Sequência de DNA/veterináriaRESUMO
The Escherichia coli F18 receptor locus (ECF18R) has been genetically mapped to the halothane linkage group on porcine Chromosome (Chr) 6. In an attempt to obtain candidate genes for this locus, we isolated 5 cosmids containing the alpha (1,2)fucosyltransferase genes FUT1, FUT2, and the pseudogene FUT2P from a porcine genomic library. Mapping by fluorescence in situ hybridization placed all these clones in band q11 of porcine Chr 6 (SSC6q11). Sequence analysis of the cosmids resulted in the characterization of an open reading frame (ORF), 1098 bp in length, that is 82.3% identical to the human FUT1 sequence; a second ORF, 1023 bp in length, 85% identical to the human FUT2 sequence; and a third FUT-like sequence thought to be a pseudogene. The FUT1 and FUT2 loci therefore seem to be the porcine equivalents of the human blood group H and Secretor loci. Direct sequencing of the two ORFs in swine being either susceptible or resistant to adhesion and colonization by F18 fimbriated Escherichia coli (ECF18) revealed two polymorphisms at bp 307 (M307) and bp 857 (M857) of the FUT1 ORF. Analysis of these mutations in 34 Swiss Landrace families with 221 progeny showed close linkage with the locus controlling resistance and susceptibility to E. coli F18 adhesion and colonization in the small intestine (ECF18R), and with the locus of the blood group inhibitor S. A high linkage disequilibrium of M307-ECF18R in Large White pigs makes the M307 mutation a good marker for marker-assisted selection of E. coli F18 adhesion-resistant animals in this breed. Whether the FUT1 or possibly the FUT2 gene products are involved in the synthesis of carbohydrate structures responsible for bacterial adhesion remains to be determined.
Assuntos
Adesinas de Escherichia coli/genética , Cromossomos/genética , Fucosiltransferases/genética , Pseudogenes/genética , Receptores Imunológicos/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Mapeamento Cromossômico , Cosmídeos , Marcadores Genéticos , Humanos , Hibridização in Situ Fluorescente , Desequilíbrio de Ligação , Dados de Sequência Molecular , Mutação , Fases de Leitura Aberta , Polimorfismo Genético , Homologia de Sequência do Ácido Nucleico , Suínos , Galactosídeo 2-alfa-L-FucosiltransferaseRESUMO
Genetically directed representational difference analysis (GDRDA) allows to isolate DNA fragments that differ between complex genomes. This approach was applied in the present work to isolate Y-specific bovine sequences. Of eight isolated and cloned fragments, two proved to be Y-specific.
Assuntos
Bovinos/genética , Cromossomo Y , Animais , Sequência de Bases , Clonagem Molecular , Primers do DNA , Sondas de DNA , Feminino , Masculino , Dados de Sequência Molecular , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da Polimerase/veterinária , Caracteres SexuaisRESUMO
Gene mapping in cattle has progressed rapidly in recent years largely owing to the introduction of powerful genetic markers, such as the microsatellites, and through advances in physical mapping techniques such as synteny mapping and fluorescence in situ hybridization (FISH). Microsatellite markers are often not physically mapped because they are generally isolated from small insert plasmid libraries, which makes their chromosomal localization inefficient. In this report we describe the FISH mapping of a large group of cosmid-derived bovine microsatellite markers, as our contribution to the European mapping initiative, BovMap. One objective of BovMap is to develop a set of anchored loci for the cattle genome map. Two cosmid libraries were screened with probes corresponding to the (AC)n microsatellite motif. Positive clones were mapped by FISH, and then a subset was further analyzed by sequencing the region flanking the microsatellite repeat. In total, 58 clones were hybridized with chromosomes and identified loci on 22 of the 31 different bovine chromosomes. Three clones contained satellite DNA. Two or more markers were placed on 12 chromosomes. Sequencing of the microsatellites and flanking regions was performed directly from 43 cosmids, as previously reported (Ferretti et al. Anim. Genet. 25, 209-214, 1994). Primers were developed for 39 markers and used to describe the polymorphism associated with the corresponding loci.
Assuntos
Bovinos/genética , Mapeamento Cromossômico , Repetições de Microssatélites , Animais , Sequência de Bases , Cosmídeos/genética , Primers do DNA , Marcadores Genéticos , Hibridização in Situ Fluorescente , Dados de Sequência MolecularRESUMO
As a new approach to parentage control we developed two multiplex coamplification polymerase chain reaction (PCR) systems containing a total of six different short tandem repeat (STR) loci; the microsatellite polymorphisms were visualized by automated fluorescence detection on the Applied Biosystems 373 DNA Sequencer with 672 Genescan Analysis software. Allele frequency data were determined from 238 animals. Thirty-five bovine parentage control cases not solvable by conventional blood typing could be solved.
