Transcription Regulation of Sex-Biased Genes during Ontogeny in the Malaria Vector Anopheles gambiae

Abstract

In Anopheles gambiae, sex-regulated genes are responsible for controlling gender dimorphism and are therefore crucial in determining the ability of female mosquitoes to transmit human malaria. The identification and functional characterization of these genes will shed light on the sexual development and maturation of mosquitoes and provide useful targets for genetic control measures aimed at reducing mosquito fertility and/or distorting the sex ratio.We conducted a genome wide transcriptional analysis of sex-regulated genes from early developmental stages through adulthood combined with functional screening of novel gonadal genes. Our results demonstrate that the male-biased genes undergo a major transcription turnover starting from larval stages to adulthood. The male biased genes at the adult stage include a significant high number of unique sequences compared to the rest of the genome. This is in contrast to female-biased genes that are much more conserved and are mainly activated during late developmental stages.The high frequency of unique sequences would indicate that male-biased genes evolve more rapidly than the rest of the genome. This finding is particularly intriguing because A. gambiae is a strictly female monogamous species suggesting that driving forces in addition to sperm competition must account for the rapid evolution of male-biased genes. We have also identified and functionally characterized a number of previously unknown A. gambiae testis- and ovary-specific genes. Two of these genes, zero population growth and a suppressor of defective silencing 3 domain of the histone deacetylase co-repressor complex, were shown to play a key role in gonad development.

Sexual dimorphism in the Drosophila melanogaster (Diptera: Drosophilidae) metabolome increases throughout development

“…This pattern of sexual dimorphism throughout development mirrors the results of our transcriptomic analyses and is also consistent with other studies that show an increasingly sexually dimorphic transcriptome throughout development (Magnusson et al, 2011;Zhao et al, 2011;Ingleby et al, 2016). Our attempt to link previous transcriptomic data with the new metabolomic data was intended as exploratory only.…”

The genetics of obligate parthenogenesis in an aphid species and its consequences for the maintenance of alternative reproductive modes

“…Suppressor genes are well known in plants where they are particularly involved in the expression of nuclear male-sterility (Li et al, 2004). In insects, suppressors negatively modulate the 'Notch' pathways, regulating cellular differentiation in Drosophila (Nagel and Preiss, 2011) and are involved in the failure in male and female gonad development in the mosquito Anopheles gambiae (Magnusson et al, 2011). Our hypothesis that reproductive mode in S. avenae is determined by the combined effect of one major gene (A) and one suppressor (S) is the simplest explanation for the heterogeneous F1 progeny observed in the OP Â OP and CP Â OP crosses, although observed proportions of OP clones were often significantly lower than those predicted according to our two-gene model.…”

Spermless males elicit large-scale female responses to mating in the malaria mosquito Anopheles gambiae

“…gambiae ortholog of zpg (AGAP006241) (28), a gene determining germ cell development (20). The dszpg was prepared according to the manufacturer's guidelines (Ambion), using a PCR template that was amplified from mosquito cDNA using primers with T7 overhangs (forward primer 5′-TAATACGACTCACTATAGGGCTCGTGAACGTG-ATCTTTTCC-3′ and reverse primer 5′-TAATACGACTCACTATAGGGCGGCCCG-ACGAAGTGG-3′) (28). The expression of the eGFP fluorescent marker in the sperm cells (6) allowed us to screen at the pupal stage for male individuals that did not develop sperm.…”