RESUMO
A number of studies have mapped QTL regulating porcine fatness and growth traits to the region of the major histocompatibility complex (MHC) on porcine chromosome 7 using various experimental crosses. The QTL results from crosses using the Chinese Meishan (MS) (slow growing and fat) are particularly interesting because the MS alleles have been found to be associated with increased growth rate and reduced backfat depth. We investigated these QTL further in a composite population derived previously over eight generations by intercrossing Meishan and the European Large White breeds. Genotype information from 32 markers in a 15cM target region was used in linkage and association analyses. A two-step variance component analysis identified QTL for three growth-related traits, explaining 19 â¼ 24% of the phenotypic variance with a confidence interval of 4 cM in the target region. SNP association analyses found that ss181128966 and ss181128924 within the QTL interval were strongly associated with the growth traits. Only weak signals for an effect on backfat depth were found in the association and linkage analyses, possibly because of past directional selection in the composite population.
Assuntos
Complexo Principal de Histocompatibilidade , Carne , Locos de Características Quantitativas , Sus scrofa/crescimento & desenvolvimento , Sus scrofa/genética , Tecido Adiposo/crescimento & desenvolvimento , Animais , Cruzamento , Polimorfismo de Nucleotídeo Único , Característica Quantitativa HerdávelRESUMO
Kit ligand (KITLG) is the ligand for the type III receptor tyrosine kinase KIT. Studies of the KIT/KITLG pathway in a number of mammalian species have shown that it is important for the development of stem cell populations in haematopoietic tissues, germ cells in reproductive organs and the embryonic migrating melanoblasts that give rise to melanocytes. Consequently, mutations in the pathway may result in a range of defects including anaemia, sterility and de-pigmentation. The cDNA sequence of the porcine KITLG gene has been reported previously, and is an attractive candidate locus for moderating coat colour in pigs. In this paper we report the gene structure and physical mapping of the porcine gene. We also report the identification of polymorphisms in the gene, one of which was used to confirm linkage to chromosome 5. Preliminary RNA expression studies using a panel of tissues have shown that in addition to the known variant lacking exon 6, there is alternative splicing of exon 4. However, little evidence was found for the KITLG gene being linked to variation in colour in a Meishan x Large White cross.
Assuntos
Expressão Gênica , Cor de Cabelo/genética , Polimorfismo Genético , Fator de Células-Tronco/genética , Sus scrofa/genética , Processamento Alternativo , Animais , Sequência de Bases , Éxons , Ligação Genética , Genoma , Íntrons , Dados de Sequência Molecular , Fases de Leitura Aberta , Mapeamento Físico do Cromossomo , Locos de Características QuantitativasAssuntos
Tecido Adiposo/metabolismo , Hidrocarboneto de Aril Hidroxilases/genética , Arilsulfotransferase/genética , Oxigenases de Função Mista/genética , Escatol/metabolismo , Suínos/genética , Alelos , Animais , Composição Corporal/genética , Mapeamento Cromossômico , Citocromo P-450 CYP2A6 , Ligação Genética , Marcadores Genéticos , Genótipo , Repetições de Microssatélites , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Suínos/anatomia & histologia , Suínos/metabolismoRESUMO
The porcine cytochrome-p450 2E1 (CYP2E1) gene was isolated by screening a pig BAC library and partially sequenced. This sequence information was used to identify six single nucleotide polymorphisms (SNPs) within the CYP2E1 gene and its promoter. In addition, a microsatellite marker tightly linked to the CYP2E1 gene was subcloned from the BAC. One of these markers was used to map the CYP2E1 gene distal of SWC27 on SSC14, well outside reported quantitative trait loci on SSC14 for skatole, indole and taste test measures of boar taint. However, in a population of commercial pigs scored for backfat skatole levels, there was evidence of association between a SNP in the CYP2E1 promoter and skatole deposition, although there was no significant association between this SNP and skatole levels in the experimental cross.
Assuntos
Mapeamento Cromossômico , Citocromo P-450 CYP2E1/genética , Escatol/metabolismo , Sus scrofa/genética , Tecido Adiposo/metabolismo , Animais , Sequência de Bases , Cromossomos Artificiais Bacterianos/genética , Clonagem Molecular , Cruzamentos Genéticos , Primers do DNA , Frequência do Gene , Repetições de Microssatélites/genética , Dados de Sequência Molecular , Polimorfismo de Fragmento de Restrição , Polimorfismo de Nucleotídeo Único/genética , Análise de Sequência de DNA , Sus scrofa/metabolismoRESUMO
The porcine PER1 gene was mapped to chromosome 12q1.4-->q1.5 using fluorescence in situ hybridisation. A polymorphic microsatellite marker (S0601) was isolated from a BAC clone shown to contain the PER1 gene. Linkage analysis assigned S0601 distal to ALOX12 on SSC12, providing further evidence for the conservation of synteny between HSA17 and SSC12. RT-PCR analysis demonstrated the expression of PER1 in all 11 tissues tested, consistent with the data from other mammalian species. Part of the PER1 gene was sequenced, homologous to exons 2-14 of the human gene and encoding the N-terminus of porcine PER1. The predicted amino acid sequence of the partial pig PER1 protein shares over 96% identity with its human orthologue.
Assuntos
Mapeamento Cromossômico , Perfilação da Expressão Gênica , Proteínas Nucleares/genética , Mapeamento Físico do Cromossomo , Suínos/genética , Animais , Proteínas de Ciclo Celular , Sequência Conservada/genética , Éxons/genética , Humanos , Hibridização in Situ Fluorescente , Escore Lod , Repetições de Microssatélites/genética , Proteínas Circadianas Period , Polimorfismo Genético/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , SinteniaAssuntos
Ligação Genética/genética , Mapeamento Físico do Cromossomo , Receptores de Superfície Celular/genética , Receptores Citoplasmáticos e Nucleares/genética , Suínos/genética , Animais , Feminino , Hibridização in Situ Fluorescente , Escore Lod , Masculino , Repetições de Microssatélites/genética , Polimorfismo Genético/genética , Receptores de MelatoninaRESUMO
The alternatively-spliced Caenorhabditis elegans gbr-2/avr-14 gene encodes two subunits of the nematode ligand-gated chloride channel family which forms an important molecular target for the avermectin and related anthelminthics. We used reverse transcriptase-polymerase chain reaction (RT-PCR) techniques to isolate cDNAs encoding the products of the gbr-2/avr-14 orthologues from the parasitic nematodes Haemonchus contortus and Ascaris suum. The predicted polypeptides possess all the characteristics of subunits of the ligand-gated chloride channels, sharing greater than 80% amino-acid identity with their counterparts in C. elegans and with partial sequences from the filarial species Onchocerca volvulus and Dirofilaria immitis. The pattern of alternative splicing of the gbr-2/avr-14 gene observed in C. elegans is conserved in H. contortus but may not be in A. suum. Affinity-purified anti-GBR-2 antibodies were used to study the expression of these subunits in adult worms and they reacted specifically with the nerve ring, the ventral and dorsal nerve cords, the anterior portion of the dorsal sub-lateral cord and motor-neuron commissures in H. contortus. Specific immunofluorescence of the nerve cords was confirmed in A. suum; isolated muscle cells did not react with the antibody.
Assuntos
Ascaris suum/genética , Canais de Cloreto/genética , Genes de Helmintos/genética , Haemonchus/genética , Ativação do Canal Iônico , Processamento Alternativo , Sequência de Aminoácidos , Animais , Caenorhabditis elegans/genética , Clonagem Molecular , DNA/genética , Dados de Sequência Molecular , Sistema Nervoso/química , RNA Mensageiro/genética , Homologia de Sequência de Aminoácidos , Distribuição TecidualRESUMO
Seasonal infertility in sows is a problem in the pig industry characterized by delayed onset of puberty in summer and decreased farrowing rate resulting from silent oestrus and aborted pregnancy. Summer infertility is thought to be influenced by heat, sunburn and stress. However, the strongest contributory factor is photoperiod. The difference in seasonality between wild boar and commercial pig breeds suggests that there may be a genetic component to this trait. The maps and associated molecular tools emerging from the pig genome project have created opportunities to examine the genetic component of seasonal infertility. We are identifying and mapping genes that are likely to be involved in biological clock mechanisms and the melatonin pathways as candidate seasonality genes.
Assuntos
Mapeamento Cromossômico , Genoma , Infertilidade/veterinária , Suínos/genética , Aborto Animal/genética , Animais , Feminino , Infertilidade/genética , Melatonina/genética , Fotoperíodo , Gravidez , Estações do AnoRESUMO
A rabbit antiserum was raised against a synthetic peptide corresponding to a region near the N-terminus of the Haemonchus contortus inhibitory amino acid receptor subunit, HG1. The antiserum recognized a recombinant form of the N-terminal domain of the subunit on Western blots and reacted with the ventral nerve cord of H. contortus in immunofluorescence experiments. Immunofluorescence was also detected in specific head neurons of H. contortus: these were tentatively identified as ring motor- and inter-neurons, plus a possible sensory neuron equivalent to the AQR cell of Caenorhabditis elegans. In the roundworm Ascaris suum, immunoreactivity was limited to the muscle arms, the post-synaptic component of the neuromuscular junction. The possible ligand of receptors containing the HG1 subunit is discussed in the light of this expression pattern.