Ontology highlight
ABSTRACT:
PROVIDER: PRJNA525249 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Genomes of closely-related species or populations often display localized regions of enhanced relative sequence divergence, termed genomic islands. It has been proposed that these islands arise through selective sweeps and/or barriers to gene flow. Here, we genetically dissect a genomic island that controls flower color pattern differences between two subspecies of Antirrhinum, A.m.striatum and A.m.pseudomajus, and relate it to clinal variation across a natural hybrid zone. We show that selective sweeps likely raised relative divergence at two tightly-linked MYB-like transcription factors, leading to distinct flower patterns in the two subspecies. The two patterns provide alternate floral guides and create a strong barrier to gene flow where populations come into contact. This barrier affects the selected flower color genes and tightly linked loci, but does not extend outside of this domain, allowing gene flow to lower relative divergence for the rest of the chromosome. Thus, both selective sweeps and barriers to gene flow play a role in shaping genomic islands: sweeps cause elevation in relative divergence while heterogeneous gene flow flattens the surrounding “sea”, making the island of divergence stand out. By showing how selective sweeps establish alternative adaptive phenotypes that lead to barriers to gene flow, our study sheds light on possible mechanisms leading to reproductive isolation and speciation.
2018-08-18 | GSE118621 | GEO
Project description:To study recombination at the fine-scale, we used high-throughput sequencing of 300 to 1,000 crossovers within the RAC1 R gene hotspot. This revealed focused intragenic crossovers, overlapping exons encoding the TIR, NBS and LRR domains. To examine the role of recombination pathways, we repeated this experiment in recq4a recq4b, fancm and recq4a recq4b fancm mutants. Finally, in order to investigate how varying patterns of interhomolog divergence influence local patterns of crossover frequency, we repeated RAC1 pollen typing sequencing in different F1 hybrids.
2018-07-01 | E-MTAB-6333 | biostudies-arrayexpress
Project description:Archaeospora ecuadoriana sp. nov. from a mountainous biodiversity hotspot area in Ecuador, and transfer of Palaeospora spainiae to Archaeospora, as A. spainiae comb. nov.
| PRJEB32970 | ENA
Project description:Meiotic recombination is required for the segregation of homologous chromosomes and is essential for fertility. The DNA double strand breaks (DSBs) that initiate meiotic recombination are directed by sequence-specific DNA binding of the PRDM9 protein. Gradual elimination of PRDM9 binding sites by gene conversion is thought to result in the hotspot erosion while mutations affecting DNA binding specificity of PRDM9 will create the new sets of hotspots. To better understand evolutionary turnover of recombination hotspots we mapped DSB hotspots in six inbred mouse strains representing all four major subspecies of Mus musculus and in their F1 hybrids. We found that hotspot erosion governs the preferential usage of some Prdm9 alleles over others in hybrid mice and increases sequence diversity specifically at hotspots that become active in the hybrids. As crossovers are disfavored at such hotspots, we propose that sequence divergence generated by hotspot turnover creates impediments for recombination in hybrids, potentially leading to reduction in fertility and eventually, speciation.
2016-02-03 | GSE75419 | GEO
Project description:Local adaptation is often a product of environmental variations in geographical space and has implications for biodiversity conservation. We investigated the role of latitudinal heterogeneity in climate on the organization of genetic and phenotypic variation in the dominant coastal tree Avicennia schaueriana. In a common garden experiment, samples from an equatorial region, with pronounced seasonality in precipitation, accumulated less biomass, and showed lower stomatal conductance and transpiration, narrower xylem vessels, smaller leaves and higher reflectance of long wavelengths by the stem epidermis than samples from a subtropical region, with seasonality in temperature and no dry season. Transcriptomic differences identified between trees sampled under field conditions at equatorial and subtropical sites, were enriched in functional categories such as responses to temperature, solar radiation, water deficit, photosynthesis and cell wall biosynthesis. Remarkably, the diversity based on genome-wide SNPs revealed a north-south genetic structure and signatures of selection were identified for loci associated with photosynthesis, anthocyanin accumulation and the responses to osmotic and hypoxia stresses. Our results suggest the existence of divergence in key resource-use characteristics, likely driven by seasonality in water deficit and solar radiation. These findings provide a basis for conservation plans and for predicting coastal plants responses to climate change.
2020-05-15 | GSE116060 | GEO
Project description:We used the bioluminescent squid symbiont, Vibrio fischeri, to identify essential regulatory factors that control expression and function of a strain-specific T6SS encoded within a genomic island. Random transposon mutagenesis revealed that three genes located on the T6SS2-encoding genomic island are necessary to activate expression of a T6SS reporter. We used a proteomics approach to identify proteins that were differentially abundant in mutant strains compared to the wild type when cells were grown in a high-viscosity media.
2021-08-24 | PXD017722 | Pride
Project description:Cichlids fishes exhibit extensive phenotypic diversification and speciation. In this study we integrate transcriptomic and proteomic signatures from two cichlids species, identify novel open reading frames (nORFs) and perform evolutionary analysis on these nORF regions. We embark comparative transrcriptomics and proteogenomic analysis of two metabolically active tissues, the testes and liver, of two cichlid species Oreochromis niloticus (Nile tilapia, ON) and Pundamilia nyererei (Makobe Island, PN). Our results suggest that the time scale of speciation of the two species can be better explained by the evolutionary divergence of these nORF genomic regions.
2021-05-17 | GSE150744 | GEO
Project description:Background: Array comparative genomic hybridization (aCGH) is commonly used to screen different types of genetic variation in humans and model species. Here, we performed aCGH using an oligonucleotide gene-expression array for a non-model species, the intertidal snail Littorina saxatilis. First, we tested what types of genetic variation can be detected by this method using direct re-sequencing and comparison to the Littorina genome draft. Secondly, we performed a genome-wide comparison of four closely related Littorina species: L. fabalis, L. compressa, L. arcana and L. saxatilis and of populations of L. saxatilis found in Spain, Britain and Sweden. Finally, we tested whether we could identify genetic variation underlying “Crab” and “Wave” ecotypes of L. saxatilis. Results: We could reliably detect copy number variations, deletions and high sequence divergence (i.e. above 3%), but not single nucleotide polymorphisms. The overall hybridization pattern and number of significantly diverged genes were in close agreement with earlier phylogenetic reconstructions based on single genes. The trichotomy of L. arcana, L. compressa and L. saxatilis could not be resolved and we argue that these divergence events have occurred recently and very close in time. We found evidence for high levels of segmental duplication in the Littorina genome (10% of the transcripts represented on the array and up to 23% of the analyzed genomic fragments); duplicated genes and regions were mostly the same in all analyzed species. Finally, this method discriminated geographically distant populations of L. saxatilis, but we did not detect any significant genome divergence associated with ecotypes of L. saxatilis. Conclusions: The present study provides new information on the sensitivity and the potential use of oligonucleotide arrays for genotyping of non-model organisms. Applying this method to Littorina species yields insights into genome evolution following the recent species radiation and supports earlier single-gene based phylogenies. Genetic differentiation of L. saxatilis ecotypes was not detected in this study, despite pronounced innate phenotypic differences. The reason may be that these differences are due to single-nucleotide polymorphisms.
2014-07-29 | GSE59825 | GEO