Project description:Color is an important trait in nature, playing a role in selection and speciation. The most important colorants in crustaceans are carotenoids, which in complexes with carotenoid-binding proteins provide an astonishing variety of colors from red to violet. Over 350 species and subspecies of amphipods (Crustacea: Amphipoda) endemic to Lake Baikal exhibit an impressive variability of colors and coloration patterns. However, the mechanisms forming this diversity are underexplored. In this work, we analyze the coloration of two species of endemic Lake Baikal amphipods, Eulimnogammarus cyaneus and E. vittatus. These species are brightly colored and, even more importantly, characterized by intraspecific color variability. We showed that the color of either species strongly correlated with the abundance of two putative carotenoid-binding proteins (the relative abundance of these proteins was higher in blue or teal-colored animals than in the orange- or yellow-colored ones.). With LC-MS/MS, we were able to identifiy these proteins, which turned out to be similar to the pheromone/odorant-binding protein family.
2020-06-04 | PXD018516 | Pride
Project description:Transcriptome sequencing of cryptic species of Lake Baikal endemic amphipods (Crustacea: Amphipoda) of the genus Eulimnogammarus
Project description:Inheritance and plasticity of epigenetic divergence characterise early stages of speciation in an incipient cichlid species of an African crater lake.
2022-06-09 | GSE174120 | GEO
Project description:Endemic lake Baikal amphipods Raw sequence reads
Project description:Suppressing spurious cryptic transcription by a repressive intragenic chromatin state featuring trimethylated lysine 36 on histone H3 (H3K36me3) and DNA methylation is critical for maintaining self-renewal capacity in mouse embryonic stem cells. In yeast and nematodes, such cryptic transcription is elevated with age, and reducing the levels of age-associated cryptic transcription extends yeast lifespan. Whether cryptic transcription is also increased during mammalian aging is unknown. We show for the first time an age-associated elevation in cryptic transcription in several stem cell populations, including murine hematopoietic stem cells (mHSCs) and neuronal stem cells (NSCs) and human mesenchymal stem cells (hMSCs). Using DECAP-seq, we mapped and quantified age-associated cryptic transcription in hMSCs aged in vitro. Regions with significant age-associated cryptic transcription have a unique chromatin signature: decreased H3K36me3 and increased H3K4me1, H3K4me3, and H3K27ac with age. Furthermore, genomic regions undergoing such age-dependent chromatin changes resemble known promoter sequences and are bound by the promoter-associated protein TBP even in young cells. Hence, the more permissive chromatin state at intragenic cryptic promoters likely underlies the increase of cryptic transcription in aged mammalian stem cells.
2021-07-15 | GSE156406 | GEO
Project description:Endemic lake Baikal amphipods Transcriptome Shotgun Assembly project
Project description:Cryptic genetic variants exert minimal or no phenotypic effects alone but have long been hypothesized to form a vast, hidden reservoir of genetic diversity that drives trait evolvability through epistatic interactions. This classical theory has been reinvigorated by pan-genome sequencing, which is continually exposing cis-regulatory variation, along with widespread gene duplications and paralog diversification as an underappreciated source of cryptic variation within gene families and the regulatory networks in which they function. However, empirical testing of this hypothesis has been hindered by intractable genetics, limited allelic diversity, and inadequate phenotypic resolution. Here, guided by natural and engineered cis-cryptic variants in a recently evolved paralogous pair, we identified an additional pair of redundant trans regulators, establishing a regulatory network that controls tomato inflorescence architecture. Exploiting an allelic spectrum of network components allowed a high-resolution dissection of a genotype-to-phenotype map, revealing how cryptic variants potentiate trait diversification. We combined coding mutations with a cis-regulatory allelic series in populations segregating for all four genes, systematically constructing gene dosage combinations across 216 genotypes and quantifying their effects on branching in 27,000 inflorescences. Our analysis revealed dose-dependent interactions within paralog pairs enhance branching, culminating in strong, synergistic, effects. However, modeling uncovered an unexpected layer of antagonism between paralog pairs, where accumulating mutations in one pair progressively diminished the effects of mutations in the other. Our results demonstrate how gene regulatory network architecture and complex dosage effects from paralog diversification converge to shape phenotypic space. Given the prevalence of paralog evolution in genomes, we propose that paralogous cryptic variation within regulatory networks elicits hierarchies of epistatic interactions, catalyzing bursts of phenotypic change.