A M Ramos

Iowa State University, Ames, IA, United States

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Publications (17)30.38 Total impact

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    ABSTRACT: In the mouse, homozygous animals for the high growth mutation show a 30-50% increase in growth without becoming obese. This region is homologous to the distal part of pig chromosome 5 (SSC5). A previous genome scan detected several quantitative trait loci (QTL) in this region for body composition and meat quality using a three generation Berkshire x Yorkshire resource family. In this study, the effects on swine growth, fat and meat quality traits of three genes previously identified within the mouse high growth region were analysed. The genes studied were CASP2 and RIPKI domain containing adaptor with death domain (CRADD), suppressor of cytokine signalling 2 (SOCS2) and plexinC1 (PLXNC1). In addition, the influence of two other genes located very close to this region, namely the plasma membrane calcium-transporting ATPase 1 (ATP2B1) and dual specificity phosphatase 6 (DUSP6) genes, was also investigated. Single nucleotide polymorphisms were identified and used to map these genes to the QTL region on SSC5. Results indicate significant associations between these genes and several phenotypic traits, including fat deposition and growth in pigs. The present study suggests associations of these genes with swine fat and growth related traits, but further studies are needed in order to clearly identify the genes involved in the regulation of the QTL located on SSC5.
    Journal of Animal Breeding and Genetics 10/2009; 126(5):404-12. · 1.65 Impact Factor
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    ABSTRACT: The objective of this study was to evaluate the effect of markers developed in eight genes, located in a previously detected meat quality QTL region on SSC17, on growth, fat and meat quality traits collected in commercial pig populations of different genetic backgrounds. The genes had been previously mapped to SSC17 as part of a fine-mapping effort. Association analyses were conducted between each marker and the available phenotypic traits. Results showed that three genes (CTSZ, CSTF1 and C20orf43) were significantly associated with the growth traits. In addition, CTSZ also impacted on meat colour, with the less favourable genotype for growth being associated with darker meat. The differences observed between genotypes were substantial and may be of economic importance to pig producers. These markers may be useful for selecting for faster growth or improved meat quality.
    Animal Genetics 07/2009; 40(5):774-8. · 2.58 Impact Factor
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    ABSTRACT: The specificity and utility of the swine protein-annotated oligonucleotide microarray, or Pigoligoarray (http://www.pigoligoarray.org), has been evaluated by profiling the expression of transcripts from four porcine tissues. Tools for comparative analyses of expression on the Pigoligoarray were developed including HGNC identities and comparative mapping alignments with human orthologs. Hybridization results based on the Pigoligoarray's sets of control, perfect match (PM) and deliberate mismatch (MM) probes provide an important means of assessing non-specific hybridization. Simple descriptive diagnostic analyses of PM/MM probe sets are introduced in this paper as useful tools for detecting non-specific hybridization. Samples of RNA from liver, brain stem, longissimus dorsi muscle and uterine endothelium from four pigs were prepared and hybridized to the arrays. Of the total 20,400 oligonucleotides on the Pigoligoarray, 12,429 transcripts were putatively differentially expressed (DE). Analyses for tissue-specific expression [over-expressed in one tissue with respect to all the remaining three tissues (q < 0.01)] identified 958 DE transcripts in liver, 726 in muscle, 286 in uterine endothelium and 1027 in brain stem. These hybridization results were confirmed by quantitative PCR (QPCR) expression patterns for a subset of genes after affirming that cDNA and amplified antisense RNA (aRNA) exhibited similar QPCR results. Comparison to human ortholog expression confirmed the value of this array for experiments of both agricultural importance and for tests using pigs as a biomedical model for human disease.
    Animal Genetics 06/2009; 40(6):883-93. · 2.58 Impact Factor
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    ABSTRACT: In this study, the influence of the β-lactoglobulin, prolactin and αS1-casein variants on milk production traits of three Portuguese sheep breeds, including Serra da Estrela, White Merino and Black Merino, was analyzed. The genetic variants of each marker were identified using PCR-RFLP. β-Lactoglobulin genotype AA was associated with lower milk yield in Serra da Estrela and Merino ewes. This marker also affected milk fat content in Serra da Estrela and protein content in Merino. First results regarding the influence of the sheep prolactin gene on milk production traits are reported. In the Serra da Estrela breed, ewes carrying prolactin genotype AA were significantly associated with lower milk yield, but this influence of prolactin genotypes on milk yield was not detected in Merino. Prolactin genotypes were also significantly associated with milk fat and protein contents in the Serra da Estrela breed. A suggestive effect of the αS1-casein locus on milk yield was detected in Serra da Estrela, but no associations were found between the variants of this marker with milk fat and protein content.
    Small Ruminant Research - SMALL RUMINANT RES. 01/2009; 82(2):117-121.
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    ABSTRACT: The objective of this study was to determine the effect of candidate genes on processing quality traits of US country hams. A total of 321 fresh hams of unknown breed and sex were examined and data on quality and physical traits were collected. The hams were then processed following typical US commercial dry-curing procedures for ham and data on additional traits were collected from the cured hams. Several genes involved in biological processes affecting dry-cured ham production were selected. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) tests were designed for each of the genes where polymorphisms were discovered and association analyses between each marker and the traits collected were performed. Results showed that two genetic markers were significantly associated with cured weight and yield: (i) a gene from the cathepsin family (cathepsin F) and (ii) the stearoyl-CoA desaturase (delta-9-desaturase) gene, involved in lipid metabolism. Moreover, markers that significantly affected colour traits and those having a significant impact on pH and lipid percentage were also identified. These markers could be used for screening and sorting of carcasses prior to ham processing and, eventually in pig improvement programmes designed to select animals possessing genotypes more suitable for the production of dry-cured hams.
    Journal of Animal Breeding and Genetics 09/2008; 125(4):248-57. · 1.65 Impact Factor
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    ABSTRACT: In this study, fresh and processing quality traits were collected on a total of 312 Country Hams. Phenotypic correlations between traits were estimated and numerous values were significantly different (P<0.05) from zero. Yield was significantly correlated with several fresh pork quality traits measured on the fresh hams, including subjective color (0.34) and lipid percentage (0.32). Some meat color traits were significantly correlated, including associations between the color scores taken on the fresh and cured hams. Correlations between fresh pork quality traits were also determined, with results showing significant correlations between ultimate pH and other pork quality traits. The results indicate that yield can be maximized if hams with good fresh pork quality parameters are used for curing. The correlations estimates are helpful for understanding of the biological mechanisms behind the production of dry-cured hams and can potentially be used to improve the efficiency of the dry-cured ham production chain.
    Meat Science 10/2007; 77(2):182-9. · 2.75 Impact Factor
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    ABSTRACT: Off flavours in pork sometimes produce tastes such as sourness, fishy, metallic or other non-typical flavours and are often caused by low pH. Loss of function mutations in flavin containing mono-oxygenase 3 (FMO3) are known to be associated with a fishy off flavour in both chicken eggs and cow's milk and a similar autosomal recessive disorder is present in humans resulting in a fishy odour. FMO3 is a member of a gene family that is clustered on human chromosome 1. Comparative mapping suggested that FMO3 and the remaining FMO genes (ex. FMO1 and FMO5) might map to the orthologous region on pig chromosome 9 (SSC9) where a quantitative trait locus (QTL) for off flavour was previously identified. Primers were designed to amplify FMO1, FMO3 and FMO5 gene fragments and several SNPs were discovered and genotyping tests developed. The genotypes from the Iowa State University Berkshire x Yorkshire resource population were used to linkage map FMO1 and FMO3 to SSC9 and FMO5 to pig chromosome 4 (SSC4). QTL and associations analyses were performed using the map containing FMO1 and FMO3. Results demonstrated that FMO3 and FMO1 mapped less than 1 cM away from the peak for the off flavour QTL previously detected on SSC9 and provide indications of an association between the FMO3 polymorphism and off flavour in pork.
    Journal of Animal Breeding and Genetics 03/2007; 124(1):35-8. · 1.65 Impact Factor
  • Animal Genetics 07/2006; 37(3):296-7. · 2.58 Impact Factor
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    ABSTRACT: The mitogen-activated protein kinase 8 (MAPK8), resistin (RETN), 11 beta hydroxysteroid dehydrogenase isoform 1 (HSD11B1) and protein kinase B Akt2 (AKT2) genes are all genes known to affect insulin signalling and have been implicated in the progression of obesity and type 2 diabetes in humans. In this study, polymorphisms in the porcine diabetes related MAPK8, RETN, HSD11B1 and AKT2 genes were identified, mapped and their associations with phenotypic measurements in swine were analysed. Polymorphisms detected in the MAPK8, RETN and HSD11B1 loci were used to genotype a Berkshire-Yorkshire pig breed reference family. Using linkage analysis, RETN, HSD11B1 and MAPK8 genes were mapped to pig chromosomes 2, 9 and 14, respectively, while the AKT2 gene was physically mapped to pig chromosome 6q21. Results presented here suggest associations between the polymorphisms in the MAPK8, RETN and HSD11B1 genes with several phenotypic measurements, including fat deposition traits in the pig. Because these genes have been implicated in obesity and diabetes in humans, and this study suggests associations with fat related traits, further research on these genes in swine may provide useful information on genetic factors underlying lean pork production.
    Animal Genetics 03/2005; 36(1):36-42. · 2.58 Impact Factor
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    ABSTRACT: The X-chromosome, highly conserved within mammals, has been shown to contain major quantitative trait loci (QTL) for growth and fat deposition in the pig. We have discovered a BamHI polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) marker that was assigned to the porcine X-chromosome by two-point and multi-point linkage analysis following genotyping of a three-generation Berkshire by Yorkshire reference family. The marker was positioned 9 cM telomeric to SW2126 and 15.6 cM centromeric to SW1943. Sequence flanking the marker was found to have high similarity to existing database porcine DNA repeat elements. Association analyses of the BamHI marker for growth and meat quality traits in the reference family revealed significant association with marbling (P < 0.03), 10th rib back fat (P < 0.09) and total lipid percentage (P < 0.05), as well as with loin eye area (P < 0.04), average glycolytic potential (P < 0.03) and average lactate content (P < 0.04). Further studies are required to determine the X-chromosome functional gene affecting fat deposition and growth in the pig.
    Animal Genetics 11/2004; 35(5):401-3. · 2.58 Impact Factor
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    ABSTRACT: We have developed software, called Expeditor, that can be used to combine known gene structure information from human and coding sequence information from farm animal species for a streamlined primer design in target farm animal species. This software has many utilities, which include PCR-based SNP discovery for identification of genes/markers associated with economically important traits in farm animals, comparative mapping analysis, and evolution studies. The use of this software helps minimize tedious manual operations and reduces the chance of errors by more conventional approaches.
    Journal of Heredity 01/2004; 96(1):80-2. · 2.00 Impact Factor
  • Animal Genetics 01/2004; 34(6):469-70. · 2.58 Impact Factor
  • Animal Genetics 01/2004; 34(6):469. · 2.58 Impact Factor
  • Animal Genetics 07/2002; 33(3):228-9. · 2.58 Impact Factor
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    ABSTRACT: SUMMARY - A large number of autochthonous breeds of domestic animals are endangered. The Portuguese indigenous pig breed Bísaro is reduced to a small number of animals mostly restricted to the Trás-os-Montes province. In order to prevent its extinction and preserve genetic variability fast measures are needed. Among molecular markers to assess the genetic variability microsatellites are the most widely used. No such markers have yet been described to be specific for this breed. This work aims to identify VNTRs (Variable Number of Tandem Repeats) among the populations of Bísaro and to sequence their conserved flanking regions to develop primers for PCR (Polymerase Chain Reaction) amplification of microsatellites in order to assess the genetic variability within and among populations. Such data can be used in future selection programs. A large number of recombinant clones is being screened by hybridization using (TG)10 and (TC)10 synthetic oligonucleotides as probes and (TG)n microsatellites were found to be more frequent in this breed.
    01/2000;
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    ABSTRACT: Para ser efectivos, las estrategias para la conservación y mejora de las razas porcinas locales deben incluir idealmente tanto su caracterización genética como fenotípica. En este estudio, la información fenotípica fue recogida de individuos pertenecientes a las razas portuguesas Alentejana y Bísaro. Las muestras de ADN de estos animales fueron entonces analizadas para la variación de 6 loci Tipo I para profundizar en el origen y la integridad de estas razas. La variación detectada en estos loci fue muy baja en el Alentejano y de baja a intermedia en el Bísaro. La asociación de cada marcador con una serie de caracteres productivos fueron analizadas en el Bísaro. Los resultados sugieren que algunos de estos genes pueden estar asociados con variaciones significativas de esos caracteres. La información derivada de la caracterización de las razas porcinas locales a nivel molecular deben apoyar los esfuerzos en conservación y deben también ser utilizadas en el futuro en programas de selección asistida por marcadores.
    Archivos de zootecnia, ISSN 0004-0592, Vol. 52, Nº 198, 2003, pags. 255-264.
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Publication Stats

82 Citations
30.38 Total Impact Points

Institutions

  • 2004–2009
    • Iowa State University
      • Department of Animal Science
      Ames, IA, United States
    • Universidade Federal de Viçosa (UFV)
      • Departamento de Zootecnia
      Brasília, Distrito Federal, Brazil
  • 2002–2009
    • Universidade de Trás-os-Montes e Alto Douro
      • Departamento de Zootecnia
      Vila Real, Vila Real, Portugal