Title : The evolutionary fate of heterogeneous gene duplications: A precarious overdominant equilibrium between environment, sublethality and complementation - Milesi_2018_Mol.Ecol_27_493 |
Author(s) : Milesi P , Assogba BS , Atyame CM , Pocquet N , Berthomieu A , Unal S , Makoundou P , Weill M , Labbe P |
Ref : Mol Ecol , 27 :493 , 2018 |
Abstract :
Gene duplications occur at a high rate. Although most appear detrimental, some homogeneous duplications (identical gene copies) can be selected for beneficial increase in produced proteins. Heterogeneous duplications, which combine divergent alleles of a single locus, are seldom studied due to the paucity of empirical data. We investigated their role in an ongoing adaptive process at the ace-1 locus in Culex pipiens mosquitoes. We assessed the worldwide diversity of the ace-1 alleles (single-copy, susceptible S and insecticide-resistant R, and duplicated D that pair one S and one R copy), analysed their phylogeography and measured their fitness to understand their early dynamics using population genetics models. It provides a coherent and comprehensive evolutionary scenario. We show that D alleles are present in most resistant populations and display a higher diversity than R alleles (27 vs. 4). Most appear to result from independent unequal crossing-overs between local single-copy alleles, suggesting a recurrent process. Most duplicated alleles have a limited geographic distribution, probably resulting from their homozygous sublethality (HS phenotype). In addition, heterozygotes carrying different HS D alleles showed complementation, indicating different recessive lethal mutations. Due to mosaic insecticide control practices, balancing selection (overdominance) plays a key role in the early dynamics of heterogeneous duplicated alleles; it also favours a high local polymorphism of HS D alleles in natural populations (overdominance reinforced by complementation). Overall, our study shows that the evolutionary fate of heterogeneous duplications (and their long-term role) depends on finely balanced selective pressures due to the environment and to their genomic structure. |
PubMedSearch : Milesi_2018_Mol.Ecol_27_493 |
PubMedID: 29230902 |
Gene_locus related to this paper: culpi-ACHE1 , culqu-ACHE1 |
Gene_locus | culpi-ACHE1 culqu-ACHE1 |
Milesi P, Assogba BS, Atyame CM, Pocquet N, Berthomieu A, Unal S, Makoundou P, Weill M, Labbe P (2018)
The evolutionary fate of heterogeneous gene duplications: A precarious overdominant equilibrium between environment, sublethality and complementation
Mol Ecol
27 :493
Milesi P, Assogba BS, Atyame CM, Pocquet N, Berthomieu A, Unal S, Makoundou P, Weill M, Labbe P (2018)
Mol Ecol
27 :493