Project description:Caves are populated with a diverse fauna of highly adapted species that tend to exhibit a consistent suite of both regressive and constructive trait modifications. Because molecular studies of cave adaptation have largely concentrated on vertebrate models, our ability to recognize universalities in the genetic trajectories underlying cave adaptation remains limited. We have initiated efforts to elucidate the molecular evolution of the flightless small carrion beetle Ptomaphagus hirtus (Ptomaphagus hirtus), which represents one of the highly endemic signature inhabitants of the Mammoth Cave system of Kentucky. Ptomaphagus hirtus has been considered blind despite the presence of lateral eye rudiments. However, analysis of the Ptomaphagus hirtus adult head transcriptome by deep RNA sequencing reveals the conservation and expression of all essential insect phototransduction genes including a single long wavelength-sensitive opsin. Consistent with the preservation of visual ability, Ptomaphagus hirtus expresses all core members of the clock gene network and exhibits a similar degree of negative phototaxis as does a closely related flight-active species in light-dark choice assays. The structural reduction of the peripheral Ptomaphagus hirtus visual system is reflected by the lack of five eye pigmentation specific genes in the head transcriptome. Taken together our data suggest that wavelength contingent and probably also spatial vision have been lost in Ptomaphagus hirtus, while irradiance vision and contingent behavioral modules have remained preserved. We predict that the adaptive state of Ptomaphagus hirtus is representative for a large number of microphthalmic species adapted to the twilight zone of caves and other subterranean habitats Poly(A)+ transcripts were isolated from a pooled sample of 25 adult Ptomaphagus hirtus heads, reverse transcribed and sequenced on the Illumina GAII
Project description:Transcriptional networks have been shown to evolve very rapidly, prompting questions as to how such changes arise and are tolerated. Recent comparisons of transcriptional networks across species have implicated variations in the cis-acting DNA sequences near genes as the main cause of divergence. What is less clear is how these changes interact with trans-acting changes occurring elsewhere in the genetic circuit. Here, we report the discovery of a system of compensatory trans and cis mutations in the yeast AP-1 transcriptional network that allows for conserved transcriptional regulation despite continued genetic change. We pinpoint a single species, the fungal pathogen Candida glabrata, in which a trans mutation has occurred very recently in a single AP-1 family member distinguishing it from its Saccharomyces ortholog. Comparison of chromatin immunoprecipitation profiles between Candida and Saccharomyces shows that, despite their different DNA binding domains, the AP-1 orthologs regulate a conserved block of genes. This conservation is enabled by concomitant changes in the cis-regulatory motifs upstream of each gene. Thus, both trans and cis mutations have perturbed the yeast AP-1 regulatory system in such a way as to compensate for one another. This demonstrates an example of “co-evolution” between a DNA-binding transcription factor and its cis-regulatory site, reminiscent of the co-evolution of protein binding partners. 3 Experiments were performed. Three replicates CgAp1-TAP was ChIPped under MMS treatment (GSM397447..GSM397449), two replicates each of ScYap1R79K and ScYap4K252R (GSM594724..GSM594727), were ChIPped under MMS treatment.
Project description:Topological associating domains (TADs) are self-interacting genomic units crucial for shaping gene regulation patterns. Despite their importance, the extent of their evolutionary conservation and its functional implications remain largely unknown. In this study, we generate Hi-C and ChIP-seq data and compare TAD organization across four primate and four rodent species, and characterize the genetic and epigenetic properties of TAD boundaries in correspondence to their evolutionary conservation. We find 14% of all human TAD boundaries to be shared among all eight species (ultraconserved), while 15% are human-specific. Ultraconserved TAD boundaries have stronger insulation strength, CTCF binding, and enrichment of older retrotransposons, compared to species-specific boundaries. CRISPR-Cas9 knockouts of two ultraconserved boundaries in mouse models leads to tissue-specific gene expression changes and morphological phenotypes. Deletion of a human-specific boundary near the autism-related AUTS2 gene results in upregulation of this gene in neurons. Overall, our study provides pertinent TAD boundary evolutionary conservation annotations, and showcase the functional importance of TAD evolution.
2023-10-20 | GSE197926 | GEO
Project description:Bombus bifarius species delimitation
| PRJNA592825 | ENA
Project description:Species delimitation under allopatry