Project description:European sculpins (Cottus) harbor an example of a recent hybrid speciation event, which entails the invasion of a new habitat by the hybrid species. We compare the transcriptomes of both parental species and the hybrid species to understand how they differ. F2 crosses between the parent species are compared to the hybrid species and its parent species to identify unique patterns of the hybrid species due to the initial hybridization process or respectively to other processes. See the accompanying publication (Czypionka et al. 2011.Transcriptome changes after genome wide admixture in invasive sculpins Molecular Ecology no doi yet) for more information.
Project description:We compared the genome-wide expression profiles of two yeast species (S. cerevisiae and S. paradoxus) using a two-species microarray that contain species-specific probes and can thus measure the expression levels of the two species simultaneosly. In Addition, we used the array to measure expression levels of the interspecific hybrid of these yeast species, while discriminating between the alleles that correspond to the two parental species. Comparison of the between-species differences and the within-hybrid allele differences allows us to separate cis from trans effects. Also, comparison of the overall expression in the hybrids (both alleles) with their parental species allows us to analyze hybrid over-expression and under-expression. Keywords: comparative transcriptome analysis, hybrid gene expression
Project description:Hybridization between Cottus rhenanus and C. perifretum has resulted in an evolutionary young hybrid lineage of invasive Cottus that has colonized a new habitat where the parental species are not found (Nolte et al. 2005; Proc. R. Soc. B 272: 2379–2387). This CGH array was designed to screen for copy number variation among Cottus species and to find gene duplicates that are unique to the hybrid lineage (see also Dennenmoser et al. 2017; Copy number increases of transposable elements and protein coding genes in an invasive fish of hybrid origin).
Project description:We compared the genome-wide expression profiles of two yeast species (S. cerevisiae and S. paradoxus) using a two-species microarray that contain species-specific probes and can thus measure the expression levels of the two species simultaneosly. In Addition, we used the array to measure expression levels of the interspecific hybrid of these yeast species, while discriminating between the alleles that correspond to the two parental species. Comparison of the between-species differences and the within-hybrid allele differences allows us to separate cis from trans effects. Also, comparison of the overall expression in the hybrids (both alleles) with their parental species allows us to analyze hybrid over-expression and under-expression. Keywords: comparative transcriptome analysis, hybrid gene expression We analyzed four conditions (rich media, glycerol, heat shock and TSA). For each conditions, we hybridized the pooled sample of both species dyed with cy3/cy5 and a sample of the hybrid dyed with the alternate fluorescent color. Each experiment was done with 2 biological repeats, except for the rich media experiments done with 4 biological repeats.
Project description:Species of the genus Drosophila have served as favorite models in speciation studies, however genetic factors of the interspecific hybrid sterility are underinvestigated to date. Here we performed the analysis of reproductive incompatibilities of hybrid females in crossing Drosophila melanogaster females and Drosophila simulans males. Using transcriptomic data analysis, molecular, cellular and genetic approaches we analyzed differential gene expression, transposable element (TE) activity, piRNA biogenesis and functional defects of oogenesis in hybrids. A premature GSC loss was a most prominent defect of oogenesis in hybrid ovaries. Owing differential expression of genes encoding components of the piRNA pathway rhino and deadlock, functional RDCmel complex in hybrid ovaries was not assembled. At the same time the activity of RDCsim complex was maintained in hybrids, independently from the genomic origin of piRNA clusters. Despite identification of a cohort of overexpressed TEs in hybrid ovaries we found no evidences that their activity can be considered as the main cause of hybrid sterility. We revealed complex pattern of Vasa protein expression in hybrid germline, including partial AT-chX piRNA targeting of vasasim allele and significant developmental delay of vasamel expression. We came to the conclusions that complex multi-locus genetic changes between the species were responsible for hybrid sterility phenotype.