Project description:Molecular phylogenomics investigates evolutionary relationships based on genomic data. However, despite genomic sequence conservation, changes in protein interactions can occur relatively rapidly and may cause strong functional diversification. To investigate such functional evolution, we here combine phylogenomics with interaction proteomics. We develop this concept by investigating the molecular evolution of the shelterin complex, which protects telomeres, across 16 vertebrate species from zebrafish to humans covering 450 million years of evolution. Our phylointeractomics screen discovers previously unknown telomere-associated proteins and reveals how homologous proteins undergo functional evolution. For instance, we show that TERF1 evolved as a telomere-binding protein in the common stem lineage of marsupial and placental mammals. Phylointeractomics is a versatile and scalable approach to investigate evolutionary changes in protein function and thus can provide experimental evidence for phylogenomic relationships.
Project description:We used flower bud transcriptomes from Collinsia rattanii and its predominantly outcrossing sister species, C. linearis, to explore the genomic basis of mating system and phenotypic evolution in Collinsia, a self-compatible genus. Transcriptional regulation of enzymes involved in pollen formation may influence floral traits that distinguish selfing and outcrossing Collinsia species through pleiotropic functions. These patterns provide clues about parallel evolution in selfing plants.
Project description:Genomic surveys of yeast hybrid species isolated from the wild and from human-related environment, aimed at the reconstruction of the natural evolution of Saccharomyces spp. evolution
Project description:We study the genomic and developmental basis of the mammalian gliding membrane, or patagium, an adaptative trait that has repeatedly evolved in different lineages, including in closely related marsupial species. Through comparative genomic analysis of fifteen new marsupial genomes, both from gliding and non-gliding species, we find that the Emx2 locus experienced lineage-specific patterns of accelerated cis-regulatory evolution in gliding species. We confirm our finding via epigenomics, transcriptomics, and in vivo marsupial transgenics.
Project description:As a sister genus to Taxus, Pseudotaxus holds significant importance for studying the origin and evolution of the taxane biosynthesis pathway. However, the reference genome of P. chienii, the sole species of Pseudotaxus, is not yet available. We have completed a chromosome-level genome assembly of P. chienii, with a total length of 15.6 Gb. P. chienii possesses only a partial pathway for Taxol biosynthesis, which terminates before the enzyme taxane 2α-O-benzoyl transferase (TBT), a crucial enzyme responsible for the production of 10-deacetylbaccatin III. With the emergence of the Taxus genus, the limitation posed by TBT is overcome, allowing for the extension of the existing taxane biosynthesis pathway into a complete Taxol biosynthesis pathway. Protein structure analysis revealed that the structure of metal ion catalysis sites in taxadiene synthase (TS) is conserved across the Pseudotaxus and Taxus genera, providing potential sites for enhancing TS activity through enzyme engineering. This comparative genomic analysis contributes to our understanding of the origin and evolution of taxane biosynthesis within the Taxaceae family.
Project description:Little is known about broad patterns of variation and evolution of gene expression during any developmental process. Here we investigate variation in genome-wide gene expression among Drosophila simulans, Drosophila yakuba and four strains of Drosophila melanogaster during a major developmental transition-the start of metamorphosis. Differences in gene activity between these lineages follow a phylogenetic pattern, and 27% of all of the genes in these genomes differ in their developmental gene expression between at least two strains or species. We identify, on a gene-by-gene basis, the evolutionary forces that shape this variation and show that, both within the transcriptional network that controls metamorphosis and across the whole genome, the expression changes of transcription factor genes are relatively stable, whereas those of their downstream targets are more likely to have evolved. Our results demonstrate extensive evolution of developmental gene expression among closely related species.
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.
Project description:Using xenograft-based experimental evolution, we characterize the full life history from initiation to metastasis of a tumor at the genomic and transcriptomic levels.
Project description:Centromeric repetitive DNA sequences are highly variable during evolution, which are the hub for genome stability in almost all the eukaryotic organisms. However, how centromeric repeat sequences diverge rapidly among closely related species and populations, and how polyploidy contributed to the diversity of centromere among co-evolved subgenomes are largely unknown. Here, we applied the Brachypodium system to investigate the track of centromere evolution within this taxa, and their adaptation to alloploidization process. Subgenome divergent centromeric satellite repeat were discovered in tetraploid B. hybridum, and this divergent was originated form their two diploid progenitors. Furthermore, differential sequences influence the association sites with CENH3 nucleosomes on the monomer satellite repeats, and positioning of CENH3 nucleosomes on the satellite DNA are stable in each subgenome after alloploidization. Only minor intrasubgenomic variations were observed on these satellite repeats from diploid to tetraploid in B. hybridum, and no evident intersubgenomic transfer of centromeric satellite repeats after alloploidization. Pan-genome analysis reveals that the general principle of centromere dynamic within the populations in Brachypodium genomes with different polyploidy level. Our results provide an unprecedented information regarding the genomic and functional diversity of centromeric repeat DNA during evolution.