Introgression of a synthetic sex ratio distortion transgene into different genetic backgrounds of Anopheles coluzzii
Description
In order to demonstrate the phenotypic stability of a sex ratio distorter in distinct genetic backgrounds of Anopheles mosquitoes, we introgressed a sex-ratio transgene from the donor line Ag(PMB)1 by six serial backcrosses into two recipient colonies of An. coluzzii that had been isolated in Mali (ML) and Burkina Faso (BF). Life history parameters (number of eggs, hatching rate, larval mortality, pupal mortality and sex ratio), adult survival in small cages, 2La inversion karyotyping data (PCR Assay) and species-specific SNP genotyping dataset (KASP Assay) recorded in the donor parental strain Ag(PMB)1, two wild-type An.coluzzii recipient colonies, ML and BF at generation 1, 2, and 7, transgenic F1 and BC1 generations produced during introgression processes, and two backcrossed transgenic BC6 progenies were provided in five distinct excel files as raw data.
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The development of genetically modified mosquitoes (GMM) and their subsequent field release offers innovative approaches for vector control of malaria. A non-gene drive self-limiting male-bias Ag(PMB)1 strain has been developed in a 47-year-old laboratory G3 strain of Anopheles gambiae s.l. When Ag(PMB)1 males are crossed to wild-type females, expression of the endonuclease I-PpoI during spermatogenesis causes the meiotic cleavage of the X chromosome in sperm cells, leading to fertile offspring with a 95% male bias. However, WHO states that the functionality of the transgene could differ when inserted in different genetic backgrounds of An. coluzzii which is currently a predominant species in several West-African countries and thus a likely recipient for a potential release of self-limiting GMMs. In this study, we introgressed the transgene from the donor Ag(PMB)1 by six serial backcrosses into two recipient colonies of An. coluzzii that had been isolated in Mali and Burkina Faso. Scans of informative SNP markers and whole-genome sequencing analysis revealed a nearly complete introgression of chromosome 3 and X, but a remarkable genomic divergence in a large region of the chromosome 2 between the later backcrossed (BC6) transgenic offspring and the recipient paternal strains. These findings suggested to extend the backcrossing breeding strategy beyond BC6 generation and increase the introgression efficiency of critical regions that have ecological and epidemiological implications through the targeted selection of specific markers. Disregarding of differential introgression efficiency, we concluded that the phenotype of the sex ratio distorter is stabile in the BC6 introgressed An. coluzzii strains.