Project description:Whole-genome methylomes and total transcriptomes for muscle and liver tissues of Lake Malawi cichlid species characterised in the context of phenotypic diversification.
Project description:We use the continuously replacing dentition of Lake Malawi cichlid fishes to understand de-novo tooth replacement in adult vertebrates. In this system, each tooth is replaced in a one-for-one fashion every ~50 days. Here, we explore the source of epithelial stem cells for tooth replacement.
Project description:Here we use single nuclei RNA sequencing (snRNA-seq) of replacement teeth and adjacent oral lamina in Lake Malawi cichlids, species with lifelong whole-tooth replacement, to make two main discoveries. First, despite hundreds of millions of years of evolution, we demonstrate conservation of cell type gene expression across vertebrate teeth (fish, mouse, human). Second, we used an approach that combines marker gene expression and developmental potential of dental cells to uncover the transcriptional signature of stem-like cells in regenerating teeth. Our work underscores the importance of a comparative framework in the study of vertebrate oral and regenerative biology.
Project description:Here we use single nuclei RNA sequencing (snRNA-seq) of replacement teeth and adjacent oral lamina in Lake Malawi cichlids, species with lifelong whole-tooth replacement, to make two main discoveries. First, despite hundreds of millions of years of evolution, we demonstrate conservation of cell type gene expression across vertebrate teeth (fish, mouse, human). Second, we used an approach that combines marker gene expression and developmental potential of dental cells to uncover the transcriptional signature of stem-like cells in regenerating teeth. Our work underscores the importance of a comparative framework in the study of vertebrate oral and regenerative biology.
2022-02-08 | GSE193285 | GEO
Project description:Microbiome of lake Malawi
| PRJNA661593 | ENA
Project description:Lake Malawi haplochromine cichlid RAD
Project description:Resistance to pyrethroids, the only insecticide approved for bednets, threatens control of the major malaria vector, Anopheles funestus, in Malawi. To improve the management of such resistance countrywide, it is crucial to understand the dynamics and mechanisms driving resistance in the field. In this study the levels of insecticide resistance were determined across the highly endemic densely populated lake and southern agricultural area. Insecticide resistance to pyrethoids was assessed using standardized WHO bioassay methods and resistant mosquitoes were hybridized to susceptible mosquitoes. This microarray analysis revealed the key role of cytochrome P450 genes such as CYP6P9a, CYP6P9b and CYP6M7. However, a significant shift in the over-expression of these CYP450s was detected across a south/north transect, with CYP6M7 more highly over-transcribed in the two northern collection sites and the tandemly duplicated genes, CYP6P9a and CYP6P9b, more greatly over-transcribed in the south.
Project description:East African cichlid fishes have diversified in an explosive fashion, but the (epi)genetic basis of the phenotypic diversity of these fishes remains largely unknown. Although transposable elements (TEs) have been associated with phenotypic variation in cichlids, little is known about their transcriptional activity and epigenetic silencing. Here, we describe dynamic patterns of TE expression in African cichlid gonads and during early development. Orthology inference revealed an expansion of piwil1 genes in Lake Malawi cichlids, likely driven by PiggyBac TEs. The expanded piwil1 copies have signatures of positive selection and retain amino acid residues essential for catalytic activity. Furthermore, the gonads of African cichlids express a Piwi-interacting RNA (piRNA) pathway that target TEs. We define the genomic sites of piRNA production in African cichlids and find divergence in closely related species, in line with fast evolution of piRNA-producing loci. Our findings suggest dynamic co-evolution of TEs and host silencing pathways in the African cichlid radiations. We propose that this co-evolution has contributed to cichlid genomic diversity.