ABSTRACT: Sex matters in Massive Parallel Sequencing: Evidence for biases in genetic parameter estimation and investigation of sex determination systems
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:Tooth is a remarkable source of information for paleoanthropologists. Investigation of ancient dental proteomes is able to provide biomolecular data helping at understanding past life. In particular, the enamel protein amelogenin (AMEL) offers the possibility to determine the sex of the specimen. Here, we have analysed eleven 5000 year-old human teeth from a French Neolithic site using a dedicated paleoproteomics strategy for phenotypic characterization of ancient samples. We have set up a shotgun proteomics analysis based on an optimized 3-step iterative search strategy. This allowed the identification of a total number of 1496 proteins including the main proteins characteristic of dental tissues. Most of the proteins were identified by the no enzyme database search mode included in the iterative bioinformatics data analysis pipeline. This demonstrates that a number of peptides issued from randomly degraded proteins may be missed when using the conventional semi-tryptic database search mode. Based on the identification of the sex-specific peptides TALVLTPLK, IALVLTPLK and WYQSIRPPYP of amelogenin, a targeted MS approach using a parallel reaction monitoring (PRM) mode was performed to maximize the sensitivity and the reproducibility of detecting these unique peptides for sex estimation. This led to confirm the sex of individualsin all the samples.
2019-11-13 | PXD014442 | Pride
Project description:Cryptobranchid sex determination
Project description:Sex estimation of human remains from demineralized blocks of tooth enamel by liquid chromatography tandem mass spectrometry (LC- MS/MS) and proteomic analysis of sexually dimorphic amelogenin peptides. The detection of the Y-isoform of amelogenin is used to estimate male sex. The combined signal intensity of the sexually dimorphic peptides from each samples of known sex is used to establish a statistical framework for the estimation of the female sex probability.
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.
