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Parallel Functional Changes in Independent Testis-Specific Duplicates of Aldehyde dehydrogenase in Drosophila
Parallel Functional Changes in Independent Testis-Specific Duplicates of Aldehyde dehydrogenase in Drosophila
- Source :
- Molecular Biology and Evolution. 32:1029-1038
- Publication Year :
- 2015
- Publisher :
- Oxford University Press (OUP), 2015.
-
Abstract
- A large proportion of duplicates, originating from ubiquitously expressed genes, acquire testis-biased expression. Identifying the underlying cause of this observation requires determining whether the duplicates have altered functions relative to the parental genes. Typically, statistical methods are used to test for positive selection, signature of which in protein sequence of duplicates implies functional divergence. When assumptions are violat ed, however, such tests can lead to false inference of positive selection. More convincing evidence for naturally selected functional changes would be the occurrence of structural changes with similar functional consequences in independent duplicates of the same gene. We investigated two testis-specific duplicates of the broadly expressed enzyme gene Aldehyde dehydrogenase (Aldh )t hat arose in different Drosophila lineages. The duplicates show a typical pattern of accelerated amino acid substitutions relative to their broadly expressed paralogs, with statistical evidence for positive selection in both cases. Importantly, in both duplicates, width of the entrance to the substrate binding site, known a priori to influence substrate specificity, and otherwise conserved throughout the genus Drosophila, has been reduced, resulting in narrowing of the entrance. Protein structure modeling suggests that the reduction of the size of the enzyme’s substrate entry channel, which is likely to shift substrate specificity toward smaller aldehydes, is accounted for by the positively selected parallel substitutions in one duplicate but not the other. Evolution of the testis-specific duplicates was accompanied by reduction in expression of the ancestral Aldh in males, supporting the hypothesis that the duplicates may have helped resolve intralocus sexual conflict over Aldh function.
- Subjects :
- Male
Genetics
Enzyme Gene
Aldehyde dehydrogenase
Aldehyde Dehydrogenase
Biology
Intralocus sexual conflict
Evolution, Molecular
Protein sequencing
Genes, Duplicate
Testis
biology.protein
Animals
Drosophila
Female
Binding site
Molecular Biology
Gene
Discoveries
Ecology, Evolution, Behavior and Systematics
Functional divergence
Function (biology)
Subjects
Details
- ISSN :
- 15371719 and 07374038
- Volume :
- 32
- Database :
- OpenAIRE
- Journal :
- Molecular Biology and Evolution
- Accession number :
- edsair.doi.dedup.....205b3c1ec00c12a406cfd87a6e9d51c2
- Full Text :
- https://doi.org/10.1093/molbev/msu407