Tesis doctoral de Ana Ojeda Garcia
Summary selection as well as demographic processes leave recognizable footprints on the genetic variability of the genome. We have applied this general principle to study two specific porcine regions that are known to contain important causal variants: the gene igf2 on ssc2 and the fat1 qtl region on ssc4. In igf2, we genotyped 34 snps located within a 27 kb region around the g3072a causal mutation in a panel of 237 domestic pigs and 162 wild boars worldwide. We confirmed that the mutation appeared in asia, likely after domestication. We detected a clear signal of a selective sweep in international breeds. However, we did not find an overall reduction of variability in highly selected international breeds when compared with european local populations because of asian germplasm introgression. Our results suggest that genetic variability at this region is subjected to a temporal trend, with breeds in which the derived allele is fixed and others in which the selective sweep is still undergoing. as for the fat1 region, we pursued several studies that focussed on two candidate genes, fabp4 and fabp5, as well as on a 2 mb surrounding region. Again, we sequenced a wide diverse porcine panel. The main results can be summarized as follows: i) gene fabp4 was unexpectedly variable (nucleotide diversity 1%); even highly inbred pig lines, such as guadyerbas, retained a remarkable level of genetic diversity (¿ = 0.59%); ii) this variability was in stark contrast to nearby gene fabp5, also from the same molecular family, which was almost completely devoid of polymorphisms; a hka test comparing both genes was significant; iii) inference of demography using bayesian tools in a 2 mb region of ssc4 suggests that european pigs suffered a dramatic bottleneck compared to a putative ancestral population, but this reduction in variability was counterbalanced by a strong migration rate from asia to europe; and iv) the patterns of linkage disequilibrium we observed were rather erratic and, overall, haplotype blocks, when they existed, were small: this bears important implications as the design and performance of genome wide association studies in the porcine species.
Datos académicos de la tesis doctoral «Nucleotide diversity, domestication and modern breeding in pigs«
- Título de la tesis: Nucleotide diversity, domestication and modern breeding in pigs
- Autor: Ana Ojeda Garcia
- Universidad: Autónoma de barcelona
- Fecha de lectura de la tesis: 24/07/2009
Dirección y tribunal
- Director de la tesis
- Miguel Pérez Enciso
- Tribunal
- Presidente del tribunal: Miguel angel Toro ibañez
- félix Goyache goñi (vocal)
- (vocal)
- (vocal)