Project description:The Salicaceae family is of growing interest in the study of dioecy in plants because the sex determination region (SDR) has been shown to be highly dynamic, with differing locations and heterogametic systems across taxa. Previous studies investigating the mechanisms regulating sex in the genus Salix have been limited to genome resequencing and differential expression, which are mostly descriptive in nature, and functional validation of candidate sex determination genes has not been conducted. Here we use functional analysis to test a suite of previously identified candidate genes involved in sex determination and sex dimorphism in the bioenergy shrub willow Salix purpurea. Six candidate master regulator genes for sex determination were overexpressed in Arabidopsis, followed by floral proteome analysis. Eleven transcription factors with predicted roles in mediating sex dimorphism downstream of the SDR were tested using DAP-Seq in both male and female S. purpurea DNA. The results of this study provide further evidence to support models for the roles of ARR17 and GATA15 as master regulator genes of sex determination in S. purpurea, contributing to a regulatory system that is notably different from that of the related genus Populus. Two transcription factors, an AP2/ERF family gene and a homeodomain-like transcription factor, have evidence supporting roles in downstream regulation of sex dimorphism.
Project description:Due to its hemizygous mode of inheritance and role in sex determination, the X chromosome is expected to play an important role in the evolution of sexual dimorphism, and to be enriched for sexually antagonistic genetic variation. By forcing the X chromosome to only be expressed in males over many generations, we changed the selection pressures on the X to become similar to those experienced by the Y chromosome. This releases the X from any constraints arising from selection in females, and is predicted to lead to specialization for male fitness, including masculinization of phenotypes that normally experience sexually antagonistic selection. Indeed, we found evidence of this via upregulation of male-benefit sexually antagonistic genes, and downregulation of X-linked female benefit genes. Interestingly, we could detect evidence of microevolutionary changes consistent with previously documented patterns of macroevolutionary change, such as changes in expression consistent with previously established patterns of sexual dimorphism, an increase in the expression of metabolic genes related to mitonuclear conflict, and evidence that dosage compensation constitutes a constraint for male-benefit genes. These results confirm the importance of the X in the evolution of sexual dimorphism and as a source for sexually antagonistic genetic variation, and demonstrate that experimental evolution can be a fruitful method for testing theories of sex chromosome evolution. Microarray data was used to detect differences in gene expression as result of experimental evolution.
Project description:Purpose: Determine whether sex-determining genes are bivalent at the bipotential stage, poised between the testis and ovary fate, and whether H3K4me3 and H3K27me3 resolve into sex-specific patterns after sex determination, contributing to the canalization and stabilization of either the testis or ovary fate. Methods: XX and XY supporting cells of the gonad were FACS-purified before sex determination (at E10.5) and after sex determination (at E13.5), and submitted to ChIP-seq for H3K4me3, H3K27me3 and H3 as a means to normalize across cell populations. Results: We found that key sex-determining genes are bivalent at the bipotential stage. Genes that are upregulated affter sex determination are stripped of their repressive H3K27me3 mark, whereas repressed genes that promote the alternate pathway remain bivalent even after sex determination.
2019-05-07 | GSE130749 | GEO
Project description:Cryptobranchid sex determination
Project description:Purpose: In this study we employed unbiased, genome-wide techniques to identify regulatory elements during murine sex determination. Methods: We performed ATAC-seq on 60K FACS-purified XX and XY gonadal cells before and after sex determination to map nucleosome depleted regions (NDRs) indicative of regulatory elements. To determine whether these are active enhancers, we performed ChIP-seq for H3K27ac, a histone modification that marks active enhancers in both sexes and time points. Transient transgenics was performed on select enhancers to determine whether they are functional in gonads during the sex determination stage. Results: We have produced a genome wide map of potential regulatory elements and active enhancers during the process of murine sex determination. Furthermore, we validated the power of our dataset by identifying a novel enhancer downstream of Bmp2, a female-specific gene. Conclusions: This work supplies a powerful resource for identifying chromatin regulatory elements active during mammalian sex determination.
Project description:Deciphering the link between doubly uniparental inheritance of mtDNA and sex determination in bivalves: clues from comparative transcriptomics
| PRJNA417279 | ENA
Project description:Sex determination in Dreissena