Analysis of qtl and candidate genes related to prolificacy and piglet survivability in an iberian x meishan f2 population

• Autores: Anna Tomàs Sangenis
• Directores de la Tesis: Armando Sánchez Bonastre (dir. tes.)
• Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2006
• Idioma: español
• Tribunal Calificador de la Tesis: L. Silió López (presid.), Josep María Folch Albareda (secret.), Pere Arús Gorina (voc.), Romi Pena Subirá (voc.), Laura Altet Sanahujes (voc.)
• Materias:
  • Ciencias agrarias
    • Ciencias veterinarias
      • Genética
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• Resumen

  • The research of this thesis was developed within the framework of a currently ongoing project, known as the MeIbMAP project, whose main purpose is to gain knowledge about the genetic architecture of economically important traits related to reproduction efficiency in pigs. To address this issue, an F2 experimental population was created from three Iberian boars and 18 Meishan sows. These two parental breeds were selected based on their large phenotypic differences for almost all reproductive traits. This thesis reports the results obtained from the performance of a one-dimensional and a two-dimensional genome scan aimed at identifying quantitative trait loci (QTL) related to litter size traits, and the characterization of three physiological candidate genes and their associations with reproductive performance of sows and physiological and vitality variables related to the survivability of newborn piglets within the first hours of life.

    The performance of a one-dimensional scan revealed few genome-wide significant QTL with effects on the total number of piglets born (TNB) and the number of piglets born alive (NBA). The joint effect of these QTL explained almost 13% of the total phenotypic variance of both traits. A bidimensional scan allowing for multiple QTL and their interactions permitted the identification of a large number of genomic regions involved in the genetic control of litter size traits. The main effects of these QTL were attributable to dominance and epistasis effects, i.e. to the non-heritable fraction of the genetic variance, providing insight into the complexity of the genetic architecture of reproductive traits that commonly display low heritability values. Complex patterns of interactions, characterized by the involvement of more than one type of epistasis, were shown by almost all interacting QTL pairs.

    The porcine prolactin receptor (PRLR) gene was selected as a candidate gene because two polymorphisms of this gene h