Publicação
Gene function diversification upon duplication
| Resumo: | Gene duplication facilitates the evolution of new gene functions by relaxing evolutionary pressure on the duplicates. Besides pseudogenization, three outcomes can occur: both copies keep the ancestral function (e.g., Positive dosage); one maintains the ancestral function and the other gains a new function (Neofunctionalization); ancestral functions are partitioned between the copies (Subfunctionalization). Cis-regulatory evolution, mainly enhancers, has gained weight in explaining this process, due to its lesser pleiotropic nature relative to protein evolution. However, knowledge on the cis-regulatory changes responsible for duplicate functional diversification is still lacking. In our lab, we use clusters III and V of the Ly6 gene family of Drosophila melanogaster, which underwent sequential duplications during the dipteran evolution, as a gene duplication evolutionary model. At each duplication event, one of the duplicates maintained the ancestral expression pattern while the other acquired novel expression domains (Neofunctionalization). CG9336 and CG9338, found in D. melanogaster, are the most recent duplicates, having already divergent expression patterns. An interesting fact is that expression divergence is not only seen between these duplicates and the unduplicated orthologue found in Ceratitis capitata, but also between duplicates in different species of Drosophilids. Given the high frequency of duplication events within a short time-scale observed in these genes, they are a good model to study cis-regulatory evolution. In this study, I focus on the most recent duplication, D. melanogaster CG9336 and CG9338, to examine the genomic location of the enhancers responsible for the expression pattern divergence observed. Intergenic and Intronic sequences of these genes were tested on a Gal4 reporter vector for enhancer activity. All regions tested showed enhancer activity and were able to recapitulate most of the duplicates expression patterns, both new and conserved. Sequence conservation analysis was also performed for the three Drosophilid species that showed expression pattern divergence. |
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| Autores principais: | Gonzalez, Luís Manuel Baudouin, 1988- |
| Assunto: | Biologia molecular Expressão génica Duplicação de genes Teses de mestrado - 2013 |
| Ano: | 2013 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Gene duplication facilitates the evolution of new gene functions by relaxing evolutionary pressure on the duplicates. Besides pseudogenization, three outcomes can occur: both copies keep the ancestral function (e.g., Positive dosage); one maintains the ancestral function and the other gains a new function (Neofunctionalization); ancestral functions are partitioned between the copies (Subfunctionalization). Cis-regulatory evolution, mainly enhancers, has gained weight in explaining this process, due to its lesser pleiotropic nature relative to protein evolution. However, knowledge on the cis-regulatory changes responsible for duplicate functional diversification is still lacking. In our lab, we use clusters III and V of the Ly6 gene family of Drosophila melanogaster, which underwent sequential duplications during the dipteran evolution, as a gene duplication evolutionary model. At each duplication event, one of the duplicates maintained the ancestral expression pattern while the other acquired novel expression domains (Neofunctionalization). CG9336 and CG9338, found in D. melanogaster, are the most recent duplicates, having already divergent expression patterns. An interesting fact is that expression divergence is not only seen between these duplicates and the unduplicated orthologue found in Ceratitis capitata, but also between duplicates in different species of Drosophilids. Given the high frequency of duplication events within a short time-scale observed in these genes, they are a good model to study cis-regulatory evolution. In this study, I focus on the most recent duplication, D. melanogaster CG9336 and CG9338, to examine the genomic location of the enhancers responsible for the expression pattern divergence observed. Intergenic and Intronic sequences of these genes were tested on a Gal4 reporter vector for enhancer activity. All regions tested showed enhancer activity and were able to recapitulate most of the duplicates expression patterns, both new and conserved. Sequence conservation analysis was also performed for the three Drosophilid species that showed expression pattern divergence. |
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