Identification of sex determination genes and their evolution in Phlebotominae sand flies (Diptera, Nematocera)

Abstract

Background Phlebotomine sand flies (Diptera, Nematocera) are important vectors of several pathogens, including Leishmania parasites, causing serious diseases of humans and dogs. Despite their importance as disease vectors, most aspects of sand fly biology remain unknown including the molecular basis of their reproduction and sex determination, aspects also relevant for the development of novel vector control strategies. Results Using comparative genomics/transcriptomics data mining and transcriptional profiling, we identified the sex determining genes in phlebotomine sand flies and proposed the first model for the sex determination cascade of these insects. For all the genes identified, we produced manually curated gene models, developmental gene expression profile and performed evolutionary molecular analysis. We identified and characterized, for the first time in a Nematocera species, the transformer ( tra ) homolog which exhibits both conserved and novel features. The analysis of the tra locus in sand flies and its expression pattern suggest that this gene is able to autoregulate its own splicing, as observed in the fruit fly Ceratitis capitata and several other insect species. Conclusions Our results permit to fill the gap about sex determination in sand flies, contribute to a better understanding of this developmental pathway in Nematocera and open the way for the identification of sex determining orthologs in other species of this important Diptera sub-order. Furthermore, the sex determination genes identified in our work also provide the opportunity of future biotechnological applications to control natural population of sand flies, reducing their impact on public health. Electronic supplementary material The online version of this article (10.1186/s12864-019-5898-4) contains supplementary material, which is available to authorized users.

The role offruitlessin specifying courtship behaviors differs acrossDrosophilaspecies

“…Findings in other insect species of sex-specific fru splicing and/or disruption of male courtship behaviors after fruM knockdown led to the hypothesis that fru ’s role as a sex-determination switch gene was highly conserved ( 14, 15, 17, 18, 20, 21, 23, 24, 59 ). This hypothesis was also supported by findings that inserting fru genes from drosophilid species with divergent courtship behaviors into D. melanogaster males recapitulated D. melanogaster behaviors, instead of phenocopying each species’ own behaviors ( 60 ), which suggested that divergence in FruM downstream targets likely contributes to specifying species-specific behaviors.…”

Identification of the sex chromosome system in a sand fly species, Lutzomyia longipalpis s.l

“…The primary purpose of the present work was to identify the sex-determination system, but we also did a preliminary (and unsuccessful) attempt of identification of the sex-determination gene by looking at protein-coding genes is the candidate Y-linked scaffolds. This failure is quite expected: Identifying the sex-determining gene by sequence similarity is a difficult task since it varies among Diptera families, and is unknown in many of them ( Saccone et al 2011 ; Salz 2011 ; Petrella et al 2019 ). None of the candidate protein-coding genes that were identified on the Y seem good candidates for the sex-determining gene, as they either had a premature stop codon or were otherwise incomplete genes.…”

Transcriptome Profiling Reveals Genes Related to Sex Determination and Differentiation in Sugarcane Borer (Chilo sacchariphagus Bojer)

“…It has been used for the screening of genes associated with various traits in sugarcane, such as sucrose accumulation [ 39 , 40 ], smut resistance [ 41 , 42 ] and the response to low nitrogen [ 43 ]. Transcriptome analysis was also used for the identification of sex-determining genes in many insects, such as Plutella xylostella [ 44 ], Phlebotominae sand flies [ 45 ], whitefly [ 46 ], Sogatella furcifera [ 47 ] and Zeugodacus tau (Walker) [ 48 ].…”