Similar Datasets
Project description:The existence of homologies between fins and tetrapod limb skeletal parts as well as of the nature of those mechanisms underlying the transition of the former towards the latter, have been a rich source of discussion for more than a century. While the recent use of gene expression patterns to try and infer evolutionary scenarios has been a popular and successful approach, in particular the distribution of Hox transcript domains, it has failed to provide clearcut evidence as to whether fishes do have bony elements related by ancestry to tetrapod hands and feet. In tetrapods, posterior Hoxd genes transcription in digits is controlled by a well-characterized series of enhancers forming a large regulatory landscape, which has its syntenic counterpart in zebrafish. We show here that the deletion of the orthologous landscape in fishes does not affect the transcription of these genes in fin buds. Instead, it abrogates hoxd expression in the cloaca, an essential structure related to the mammalian uro-genital sinus. We also report that Hoxd gene function in the mammalian uro-genital sinus depends on enhancers located in the same regulatory landscape and thus conclude that an ancestral Hox ‘cloacal’ regulation was co-opted, in tetrapod, as a playground to subsequently accompany the evolution of both external genitals and digits regulatory landscapes, along with the emergence of these developmentally and phylogenetically related structures.
2024-04-17 | GSE250264 | GEO
Project description:The existence of homologies between fins and tetrapod limb skeletal parts as well as of the nature of those mechanisms underlying the transition of the former towards the latter, have been a rich source of discussion for more than a century. While the recent use of gene expression patterns to try and infer evolutionary scenarios has been a popular and successful approach, in particular the distribution of Hox transcript domains, it has failed to provide clearcut evidence as to whether fishes do have bony elements related by ancestry to tetrapod hands and feet. In tetrapods, posterior Hoxd genes transcription in digits is controlled by a well-characterized series of enhancers forming a large regulatory landscape, which has its syntenic counterpart in zebrafish. We show here that the deletion of the orthologous landscape in fishes does not affect the transcription of these genes in fin buds. Instead, it abrogates hoxd expression in the cloaca, an essential structure related to the mammalian uro-genital sinus. We also report that Hoxd gene function in the mammalian uro-genital sinus depends on enhancers located in the same regulatory landscape and thus conclude that an ancestral Hox ‘cloacal’ regulation was co-opted, in tetrapod, as a playground to subsequently accompany the evolution of both external genitals and digits regulatory landscapes, along with the emergence of these developmentally and phylogenetically related structures.
2024-04-17 | GSE250266 | GEO
Project description:The existence of homologies between fins and tetrapod limb skeletal parts as well as of the nature of those mechanisms underlying the transition of the former towards the latter, have been a rich source of discussion for more than a century. While the recent use of gene expression patterns to try and infer evolutionary scenarios has been a popular and successful approach, in particular the distribution of Hox transcript domains, it has failed to provide clearcut evidence as to whether fishes do have bony elements related by ancestry to tetrapod hands and feet. In tetrapods, posterior Hoxd genes transcription in digits is controlled by a well-characterized series of enhancers forming a large regulatory landscape, which has its syntenic counterpart in zebrafish. We show here that the deletion of the orthologous landscape in fishes does not affect the transcription of these genes in fin buds. Instead, it abrogates hoxd expression in the cloaca, an essential structure related to the mammalian uro-genital sinus. We also report that Hoxd gene function in the mammalian uro-genital sinus depends on enhancers located in the same regulatory landscape and thus conclude that an ancestral Hox ‘cloacal’ regulation was co-opted, in tetrapod, as a playground to subsequently accompany the evolution of both external genitals and digits regulatory landscapes, along with the emergence of these developmentally and phylogenetically related structures.
2024-04-17 | GSE250367 | GEO
Project description:The existence of homologies between fins and tetrapod limb skeletal parts as well as of the nature of those mechanisms underlying the transition of the former towards the latter, have been a rich source of discussion for more than a century. While the recent use of gene expression patterns to try and infer evolutionary scenarios has been a popular and successful approach, in particular the distribution of Hox transcript domains, it has failed to provide clearcut evidence as to whether fishes do have bony elements related by ancestry to tetrapod hands and feet. In tetrapods, posterior Hoxd genes transcription in digits is controlled by a well-characterized series of enhancers forming a large regulatory landscape, which has its syntenic counterpart in zebrafish. We show here that the deletion of the orthologous landscape in fishes does not affect the transcription of these genes in fin buds. Instead, it abrogates hoxd expression in the cloaca, an essential structure related to the mammalian uro-genital sinus. We also report that Hoxd gene function in the mammalian uro-genital sinus depends on enhancers located in the same regulatory landscape and thus conclude that an ancestral Hox ‘cloacal’ regulation was co-opted, in tetrapod, as a playground to subsequently accompany the evolution of both external genitals and digits regulatory landscapes, along with the emergence of these developmentally and phylogenetically related structures.
2024-04-17 | GSE250265 | GEO
Project description:The existence of homologies between fins and tetrapod limb skeletal parts as well as of the nature of those mechanisms underlying the transition of the former towards the latter, have been a rich source of discussion for more than a century. While the recent use of gene expression patterns to try and infer evolutionary scenarios has been a popular and successful approach, in particular the distribution of Hox transcript domains, it has failed to provide clearcut evidence as to whether fishes do have bony elements related by ancestry to tetrapod hands and feet. In tetrapods, posterior Hoxd genes transcription in digits is controlled by a well-characterized series of enhancers forming a large regulatory landscape, which has its syntenic counterpart in zebrafish. We show here that the deletion of the orthologous landscape in fishes does not affect the transcription of these genes in fin buds. Instead, it abrogates hoxd expression in the cloaca, an essential structure related to the mammalian uro-genital sinus. We also report that Hoxd gene function in the mammalian uro-genital sinus depends on enhancers located in the same regulatory landscape and thus conclude that an ancestral Hox ‘cloacal’ regulation was co-opted, in tetrapod, as a playground to subsequently accompany the evolution of both external genitals and digits regulatory landscapes, along with the emergence of these developmentally and phylogenetically related structures.
2024-04-17 | GSE250263 | GEO
Project description:The existence of homologies between fins and tetrapod limb skeletal parts as well as of the nature of those mechanisms underlying the transition of the former towards the latter, have been a rich source of discussion for more than a century. While the recent use of gene expression patterns to try and infer evolutionary scenarios has been a popular and successful approach, in particular the distribution of Hox transcript domains, it has failed to provide clearcut evidence as to whether fishes do have bony elements related by ancestry to tetrapod hands and feet. In tetrapods, posterior Hoxd genes transcription in digits is controlled by a well-characterized series of enhancers forming a large regulatory landscape, which has its syntenic counterpart in zebrafish. We show here that the deletion of the orthologous landscape in fishes does not affect the transcription of these genes in fin buds. Instead, it abrogates hoxd expression in the cloaca, an essential structure related to the mammalian uro-genital sinus. We also report that Hoxd gene function in the mammalian uro-genital sinus depends on enhancers located in the same regulatory landscape and thus conclude that an ancestral Hox ‘cloacal’ regulation was co-opted, in tetrapod, as a playground to subsequently accompany the evolution of both external genitals and digits regulatory landscapes, along with the emergence of these developmentally and phylogenetically related structures.
2024-04-17 | GSE250368 | GEO
Project description:Developmental genes are often controlled by large regulatory landscapes matching topologically associating domains (TADs). In various contexts, the associated chromatin backbone is modified by specific enhancer-enhancer and enhancer-promoter interactions. We used a TAD flanking the mouse HoxD cluster to study how these regulatory architectures are formed and deconstructed once their function achieved. We describe this TAD as a functional unit, with several regulatory sequences acting together to elicit a transcriptional response. With one exception, deletion of these sequences didn't modify the transcriptional outcome, a result at odds with a conventional view of enhancer function. The deletion and inversion of a CTCF site located near these regulatory sequences did not affect transcription of the target gene. Slight modifications were nevertheless observed, in agreement with the loop extrusion model. We discuss these unexpected results considering both conventional and alternative explanations relying on the accumulation of poorly specific factors within the TAD backbone.
| S-EPMC7185996 | biostudies-literature
Project description:The diversity of forms in multicellular organisms originates largely from the spatial redeployment of developmental genes [S. B. Carroll, Cell 134, 25-36 (2008)]. Several scenarios can explain the emergence of cis-regulatory elements that govern novel aspects of a gene expression pattern [M. Rebeiz, M. Tsiantis, Curr. Opin. Genet. Dev. 45, 115-123 (2017)]. One scenario, enhancer co-option, holds that a DNA sequence producing an ancestral regulatory activity also becomes the template for a new regulatory activity, sharing regulatory information. While enhancer co-option might fuel morphological diversification, it has rarely been documented [W. J. Glassford et al., Dev. Cell 34, 520-531 (2015)]. Moreover, if two regulatory activities are borne from the same sequence, their modularity, considered a defining feature of enhancers [J. Banerji, L. Olson, W. Schaffner, Cell 33, 729-740 (1983)], might be affected by pleiotropy. Sequence overlap may thereby play a determinant role in enhancer function and evolution. Here, we investigated this problem with two regulatory activities of the Drosophila gene yellow, the novel spot enhancer and the ancestral wing blade enhancer. We used precise and comprehensive quantification of each activity in Drosophila wings to systematically map their sequences along the locus. We show that the spot enhancer has co-opted the sequences of the wing blade enhancer. We also identified a pleiotropic site necessary for DNA accessibility of a shared regulatory region. While the evolutionary steps leading to the derived activity are still unknown, such pleiotropy suggests that enhancer accessibility could be one of the molecular mechanisms seeding evolutionary co-option.
| S-EPMC7456186 | biostudies-literature
Project description:Convergent evolution is a process that has occurred throughout the tree of life, but the historical genetic and biochemical context promoting the repeated independent origins of a trait is rarely understood. The well-known stimulant caffeine, and its xanthine alkaloid precursors, has evolved multiple times in flowering plant history for various roles in plant defense and pollination. We have shown that convergent caffeine production, surprisingly, has evolved by two previously unknown biochemical pathways in chocolate, citrus, and guaraná plants using either caffeine synthase- or xanthine methyltransferase-like enzymes. However, the pathway and enzyme lineage used by any given plant species is not predictable from phylogenetic relatedness alone. Ancestral sequence resurrection reveals that this convergence was facilitated by co-option of genes maintained over 100 million y for alternative biochemical roles. The ancient enzymes of the Citrus lineage were exapted for reactions currently used for various steps of caffeine biosynthesis and required very few mutations to acquire modern-day enzymatic characteristics, allowing for the evolution of a complete pathway. Future studies aimed at manipulating caffeine content of plants will require the use of different approaches given the metabolic and genetic diversity revealed by this study.
| S-EPMC5035902 | biostudies-literature
Project description:Spatiotemporal changes in gene expression underlie many evolutionary novelties in nature. However, the evolutionary origins of novel expression patterns, and the transcriptional control elements ("enhancers") that govern them, remain unclear. Here, we sought to explore the molecular genetic mechanisms by which new enhancers arise. We undertook a survey of closely related Drosophila species to identify recently evolved novel gene expression patterns and traced their evolutionary history. Analyses of gene expression in a variety of developing tissues of the Drosophila melanogaster species subgroup revealed high rates of expression pattern divergence, including numerous evolutionary losses, heterochronic shifts, and expansions or contractions of expression domains. However, gains of novel expression patterns were much less frequent. One gain was observed for the Neprilysin-1 (Nep1) gene, which has evolved a unique expression pattern in optic lobe neuroblasts of Drosophila santomea. Dissection of the Nep1 cis-regulatory region localized a newly derived optic lobe enhancer activity to a region of an intron that has accumulated a small number of mutations. The Nep1 optic lobe enhancer overlaps with other enhancer activities, from which the novel activity was co-opted. We suggest that the novel optic lobe enhancer evolved by exploiting the cryptic activity of extant regulatory sequences, and this may reflect a general mechanism whereby new enhancers evolve.
| S-EPMC3121811 | biostudies-literature