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. 2015 Jun 12;348(6240):1268-70.
doi: 10.1126/science.aaa2850. Epub 2015 May 21.

SEX DETERMINATION. A male-determining factor in the mosquito Aedes aegypti

Andrew Brantley Hall  1 , Sanjay Basu  2 , Xiaofang Jiang  1 , Yumin Qi  3 , Vladimir A Timoshevskiy  2 , James K Biedler  3 , Maria V Sharakhova  2 , Rubayet Elahi  4 , Michelle A E Anderson  2 , Xiao-Guang Chen  5 , Igor V Sharakhov  6 , Zach N Adelman  7 , Zhijian Tu  8
Affiliations

SEX DETERMINATION. A male-determining factor in the mosquito Aedes aegypti

Andrew Brantley Hall et al. Science. .

Abstract

Sex determination in the mosquito Aedes aegypti is governed by a dominant male-determining factor (M factor) located within a Y chromosome-like region called the M locus. Here, we show that an M-locus gene, Nix, functions as an M factor in A. aegypti. Nix exhibits persistent M linkage and early embryonic expression, two characteristics required of an M factor. Nix knockout with clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 resulted in largely feminized genetic males and the production of female isoforms of two key regulators of sexual differentiation: doublesex and fruitless. Ectopic expression of Nix resulted in genetic females with nearly complete male genitalia. Thus, Nix is both required and sufficient to initiate male development. This study provides a foundation for mosquito control strategies that convert female mosquitoes into harmless males.

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Conflict of interest statement

The authors declare no competing financial interests.

Figures

Fig. 1
Fig. 1. Nix is located within the M locus
(A) PCR for Nix in male and female genomic DNA. For all PCR experiments, a ribosomal protein gene, RPS7, was used as a positive control. (B) PCR for Nix in genomic DNA from recombinant female mJ2sensor/m A. aegypti. (C) Reverse transcription PCR expression profile of Nix from 0- to 12-hour embryo cDNA starting at 0 to 1 hour in 1-hour increments. (D) FISH with a probe for Nix and the J2 transgene in mitotic chromosomes of J2 transgenic males. (E) Nix copy number as determined by digital droplet PCR (ddPCR) on male and female genomic DNA. Error bars, mean ± SEM.
Fig. 2
Fig. 2. Knockout with CRISPR-Cas9 demonstrates that Nix is required for male development
(A) Phenotypes of injected individuals. (B) The female isoform of dsx (dsxF) is present in nix− A. aegypti detected by ddPCR. Rel. Exp., relative expression. Error bars, mean ± SEM. (C) The female isoform of fru (fruF) is present in the nix− A. aegypti detected by ddPCR. Error bars, mean ± SEM. (D) Feminization of the antennae in a nix− male individual. (E) Feminization in the genitals of a nix− male individual. (F and G) The log2 reads per kilobase per million mapped reads expression level heat map of the top 100 male-biased (F) and female-biased (G) genes in wild-type males, nix− males, and wild-type females. Two heat maps from nix− males are shown here. All other heat maps are shown in fig. S10.
Fig. 3
Fig. 3. Ectopic expression demonstrates that Nix is sufficient to initiate male development
(A) The phenotypes of nix+ females. Thirty individuals were sacrificed at the larval stage to examine gene expression and therefore have an undetermined phenotype. (B) The number of nix+ females with male-specific features from experiment 1. (C) Wild-type genitals compared with the genitals of a nix+ female, which have gonocoxites and gonostyli. (D) Wild-type testes and ovaries compared with gonads of a nix+ female, which had testes and accessory glands. Wild-type images and nix+ images are viewed under 55× and 80× magnification, respectively. AG, accessory glands; VD, vas deferens.
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References

    1. Bachtrog D, et al. PLOS Biol. 2014;12:e1001899. - PMC - PubMed
    1. Tree of Sex. Sci Data. 2014;1:140015. - PMC - PubMed
    1. Charlesworth D, Mank JE. Genetics. 2010;186:9–31. - PMC - PubMed
    1. Salz HK, Erickson JW. Fly. 2010;4:60–70. - PMC - PubMed
    1. Hasselmann M, et al. Nature. 2008;454:519–522. - PubMed

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