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Inversion polymorphisms:an insight into its molecular genetic content
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Resumo(s)
Resumo alargado em português disponível no documento
There is compelling evidence supporting an adaptive explanation for the evolution of inversion polymorphism in D.subobscura. Nevertheless, the specific mechanisms that underlie the maintenance and evolution of these polymorphisms are still in debate. The analysis of the associations between chromosomal inversions and microsatellite alleles is extremely useful to address the evolution of the genic content of inversions. Here we present a survey of 31 microsatellite loci covering the whole genome of D.subobscura and their association with chromosomal inversions on four European (Barcelona, Mount Parnes, Drøbak and Sunne) and one North American populations (Bellingham). We observed high linkage disequilibrium (LD) between most microsatellite loci and chromosomal arrangements in the colonizing population as a result of the founder event. Among European populations we have observed: i) no genetic differentiation between arrangements and within the same arrangements between populations for the sex-chromosome, ii) higher genetic differentiation between arrangements within populations than within the same arrangements between populations for chromosomes J, E and O, and iii) the arrangements of chromosome U had population-specific properties. The LD patterns between autosomal arrangements and microsatellite loci were in accordance with the genetic differentiation of the arrangements. Furthermore, we discuss whether this LD patterns in most localities are due to historical processes associated with the inversion formation or to selection. Our results provide strong support for distinct selective mechanisms on the maintenance of inversion polymorphisms, namely: local adaptation hypothesis on chromosome J, E and O, and coadaptation sensu Dobzhansky on U chromosome
There is compelling evidence supporting an adaptive explanation for the evolution of inversion polymorphism in D.subobscura. Nevertheless, the specific mechanisms that underlie the maintenance and evolution of these polymorphisms are still in debate. The analysis of the associations between chromosomal inversions and microsatellite alleles is extremely useful to address the evolution of the genic content of inversions. Here we present a survey of 31 microsatellite loci covering the whole genome of D.subobscura and their association with chromosomal inversions on four European (Barcelona, Mount Parnes, Drøbak and Sunne) and one North American populations (Bellingham). We observed high linkage disequilibrium (LD) between most microsatellite loci and chromosomal arrangements in the colonizing population as a result of the founder event. Among European populations we have observed: i) no genetic differentiation between arrangements and within the same arrangements between populations for the sex-chromosome, ii) higher genetic differentiation between arrangements within populations than within the same arrangements between populations for chromosomes J, E and O, and iii) the arrangements of chromosome U had population-specific properties. The LD patterns between autosomal arrangements and microsatellite loci were in accordance with the genetic differentiation of the arrangements. Furthermore, we discuss whether this LD patterns in most localities are due to historical processes associated with the inversion formation or to selection. Our results provide strong support for distinct selective mechanisms on the maintenance of inversion polymorphisms, namely: local adaptation hypothesis on chromosome J, E and O, and coadaptation sensu Dobzhansky on U chromosome
Descrição
Tese de mestrado, Biologia (Biologia Evolutiva e do Desenvolvimento), 2009, Universidade de Lisboa, Faculdade de Ciências
Palavras-chave
Variabilidade genética Genética das populações Marcadores moleculares Teses de mestrado