Project description:Structurally complex regions of the genome are increasingly recognized as engines of evolutionary convergence due to their propensity to generate recurrent gene duplications that give rise to similar gene expression patterns and traits across lineages. However the mutational mechanisms driving these duplications and the regulatory changes enabling novel expression patterns remain poorly understood. The primate amylase locus, marked by independent gene duplications, provides an ideal model to investigate these dynamics. Leveraging high-quality genome assemblies from 53 primates and multi-tissue transcriptomes from Old World monkeys, we reconstructed the evolutionary history of the recurrent gene duplications across the primate phylogeny. Our data suggest that lineage-specific LTR retrotransposon insertions are associated with initial structural instability, while subsequent duplications are primarily driven by non-allelic homologous recombination. Recurrent independent duplications in rhesus macaques, olive baboons, and great apes gave rise to distinct amylase gene copies with convergent expression in the pancreas and salivary glands. We found that these independent gene duplications are accompanied by episodic diversifying selection on lineage-specific copies, likely driving the emergence of functional divergence. Our comparative analyses in primates indicate that the gene ancestral to great ape AMY1 and AMY2A was expressed in both salivary glands and pancreas in the Catarrhini ancestor. The great ape–specific duplication of this ancestral gene likely facilitated subfunctionalization into salivary gland- and pancreas-specific expression, respectively. Comparative analysis of primate amylase promoter regions reveals regulatory rewiring, driven by motif turnover mediated by structural rearrangements, and partially explaining evolutionary shifts in expression. Together, our findings highlight how structural and regulatory modularity in complex genomic regions drives evolutionary innovation and molecular convergence, and we provide a genomic framework for dissecting these processes across diverse lineages.
Project description:Structurally complex regions of the genome are increasingly recognized as engines of evolutionary convergence due to their propensity to generate recurrent gene duplications that give rise to similar gene expression patterns and traits across lineages. However the mutational mechanisms driving these duplications and the regulatory changes enabling novel expression patterns remain poorly understood. The primate amylase locus, marked by independent gene duplications, provides an ideal model to investigate these dynamics. Leveraging high-quality genome assemblies from 53 primates and multi-tissue transcriptomes from Old World monkeys, we reconstructed the evolutionary history of the recurrent gene duplications across the primate phylogeny. Our data suggest that lineage-specific LTR retrotransposon insertions are associated with initial structural instability, while subsequent duplications are primarily driven by non-allelic homologous recombination. Recurrent independent duplications in rhesus macaques, olive baboons, and great apes gave rise to distinct amylase gene copies with convergent expression in the pancreas and salivary glands. We found that these independent gene duplications are accompanied by episodic diversifying selection on lineage-specific copies, likely driving the emergence of functional divergence. Our comparative analyses in primates indicate that the gene ancestral to great ape AMY1 and AMY2A was expressed in both salivary glands and pancreas in the Catarrhini ancestor. The great ape–specific duplication of this ancestral gene likely facilitated subfunctionalization into salivary gland- and pancreas-specific expression, respectively. Comparative analysis of primate amylase promoter regions reveals regulatory rewiring, driven by motif turnover mediated by structural rearrangements, and partially explaining evolutionary shifts in expression. Together, our findings highlight how structural and regulatory modularity in complex genomic regions drives evolutionary innovation and molecular convergence, and we provide a genomic framework for dissecting these processes across diverse lineages.
Project description:Altered regulatory interactions during development likely underlie a large fraction of phenotypic diversity within and between species, yet identifying specific evolutionary changes remains challenging. Analysis of single-cell developmental transcriptomes from multiple species provides a powerful framework for unbiased identification of evolutionary changes in developmental mechanisms. Here, we leverage a “natural experiment” in developmental evolution in sea urchins, where a major life history switch recently evolved in the lineage leading to Heliocidaris erythrogramma, precipitating extensive changes in early development. Comparative analyses of scRNA-seq developmental time courses from H. erythrogramma and Lytechinus variegatus (representing the derived and ancestral states respectively) reveals numerous evolutionary changes in embryonic patterning. The earliest cell fate specification events, and the primary signaling center are co-localized in the ancestral dGRN but remarkably, in H. erythrogramma they are spatially and temporally separate. Fate specification and differentiation are delayed in most embryonic cell lineages, although in some cases, these processes are conserved or even accelerated. Comparative analysis of regulator-target gene co-expression is consistent with many specific interactions being preserved but delayed in H. erythrogramma, while some otherwise widely conserved interactions have likely been lost. Finally, specific patterning events are directly correlated with evolutionary changes in larval morphology, suggesting that they are directly tied to the life history shift. Together, these findings demonstrate that comparative scRNA-seq developmental time courses can reveal a diverse set of evolutionary changes in embryonic patterning and provide an efficient way to identify likely candidate regulatory interactions for subsequent experimental validation.
Project description:Seeds of the desert shrub, jojoba (Simmondsia chinensis) are an abundant, renewable source of liquid wax-esters, which are valued additives in cosmetic products and industrial lubricants. Jojoba is relegated to its own taxonomic family, and there is little genetic information available to elucidate its phylogeny. Here we report the high-quality, 887 Mb, genome of jojoba assembled into 26 chromosomes with 23,490 protein-coding genes. The jojoba genome has only the whole-genome triplication (γ) shared among eudicots, and no recent duplications. These genomic resources coupled with extensive transcriptome, proteome and lipidome data helped to define heterogeneous pathways and machinery for lipid synthesis and storage, provided missing evolutionary history information for this taxonomically-segregated dioecious plant species, and will support efforts to improve the agronomic properties of jojoba
2020-03-11 | GSE130603 | GEO
Project description:Evolutionary history of Usnea
| PRJNA902355 | ENA
Project description:Evolutionary history of Astyanax