Tesis doctoral de Alberto Martínez Royo
This thesis focuses on the characterization and evaluation of four candidate genes (bmp15, gdf9, bmpr1b and mtnr1a) related to prolificacy and reproductive seasonality traits in the rasa aragonesa (raa) sheep breed. Bmp15, gdf9 and bmpr1b have shown influence on prolificacy in other breeds while mtnr1a can influence reproductive seasonality. the most relevant result was the discovery of a new naturally occurring mutation in the bmp15 gene in the ovine rasa aragonesa breed. This mutation is a deletion of 17 base pairs that leads to an altered amino-acid sequence which introduces a premature stop codon in the protein. Highly significant associations (p < 0.0001) were found between high and low estimated breeding values (ebvs) for prolificacy and the genotypes (xr/ x+) of the bmp15 gene in raa animals. As with other mutations found in bmp15 gene, this one is associated with both increased prolificacy and sterility in heterozygous and homozygous ewes, respectively. Furthermore, statistical analysis showed that the fecxr allele increases prolificacy by 0.3243+0.0448 lambs per sheep per parturition. an accurate, reliable and quick method was developed by duplex pcr for genetic sex determination and freemartin detection, amplifying the ovine-specific y chromosome repetitive fragment and fecx alleles of bmp15 gene in replacement ewes. This is important as it will decrease the number of infertile ewes with non-functioning ovaries sterilized in the womb by hormones from a male twin. new mutations discovered in the gdf9, bmpr1b and mtnr1a genes have not been shown to influence prolificacy in the raa as they do in other sheep breeds. However, a significant effect was found between snp606 of the mtnr1a gene and spontaneous ovulation out of the reproductive season. The t allele was associated with cyclicity in rasa aragonesa sheep while in other breeds, this was the c allele. This finding, along with the fact that this polymorphism does not result in an amino-acid substitution, suggest that snp606 may act in linkage equilibrium with a mutation in other genes responsible for breeding out of season. In this sense, new polymorphims in the promotor and coding region of the gene mtnr1a did not show any association for breeding out of season in the raa breed.
Datos académicos de la tesis doctoral «Estudio de genes con influencia en prolificidad y estacionalidad reproductiva en la raza ovina rasa aragonesa«
- Título de la tesis: Estudio de genes con influencia en prolificidad y estacionalidad reproductiva en la raza ovina rasa aragonesa
- Autor: Alberto Martínez Royo
- Universidad: Lleida
- Fecha de lectura de la tesis: 14/04/2011
Dirección y tribunal
- Director de la tesis
- Jorge Hugo Calvo Lacosta
- Tribunal
- Presidente del tribunal: joan Estany illa
- marcel Amills eras (vocal)
- Jesús Luis Yaniz perez de albeniz (vocal)
- clementina Rodellar penella (vocal)