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Journal of Animal Science Abstract - Molecular Genetics

Mitochondrial genome polymorphisms associated with longissimus muscle composition in Iberian pigs1


This article in

  1. Vol. 86 No. 6, p. 1283-1290
    Received: Sept 07, 2007
    Accepted: Feb 29, 2008
    Published: December 5, 2014

    2 Corresponding author(s):

  1. A. I. Fernández*2,
  2. E. Alves*,
  3. A. Fernández*,
  4. E. de Pedro,
  5. M. A. López-García*,
  6. C. Ovilo*,
  7. M. C. Rodríguez* and
  8. L. Silió*
  1. Departamento de Mejora Genética Animal, INIA, Ctra. de la Coruña km 7.5, 28040 Madrid, Spain, and
    Departamento de Producción Animal, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain


We carried out a study to investigate the associations between mitochondrial DNA polymorphisms and meat quality traits (intramuscular fat and protein content of the longissimus) in an Iberian porcine line named Torbiscal. The studied pigs (n = 319) belong to 9 maternal lineages and were previously assigned to 6 mitochondrial haplotypes (H1 to H6), based on Cytochrome b and Dloop sequences. Statistical analyses, following a bivariate mixed model, show a greater fat content and lower protein content in H3 haplotype carriers than H1, H2, H4, H5, and H6 haplotype carriers. The magnitudes of these differences are close to 1 g of fat and −0.5 g of protein per 100 g of muscle. To identify the causative mutation of these effects on intramuscular fat and protein contents, the complete mitochondrial DNA sequence of 6 individuals was determined, each one carrying a different mitochondrial haplotype. The alignments of these 6 complete mitochondrial sequences allowed identification of 32 substitutions and 2 indels. Two polymorphic positions were exclusively detected in H3 carriers: a synonymous transition 9104C > T in the gene-coding region of Cytochrome c oxidase subunit III and a substitution 715A > G in 12S rRNA. Genotyping results of a larger number of Torbiscal samples showed the exclusive presence of 9104T and 715G alleles in H3 carriers. The detected candidate substitutions are located in essential mitochondrial genes, and although they do not change the amino acid composition, we cannot disregard a potential change in the secondary structure of their corresponding mRNA. The usefulness of these polymorphisms as markers in selection programs requires validation of the consistency of these results in other Iberian pig lines.

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