Latest recommendations
Id | Title * | Authors * | Abstract * | Picture * ▲ | Thematic fields * | Recommender | Reviewers | Submission date | |
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11 Mar 2021
![]() Gut microbial ecology of Xenopus tadpoles across life stagesThibault Scalvenzi, Isabelle Clavereau, Mickael Bourge, Nicolas Pollet https://doi.org/10.1101/2020.05.25.110734A comprehensive look at Xenopus gut microbiota: effects of feed, developmental stages and parental transmissionRecommended by Wirulda Pootakham based on reviews by Vanessa Marcelino and 1 anonymous reviewerIt is well established that the gut microbiota play an important role in the overall health of their hosts (Jandhyala et al. 2015). To date, there are still a limited number of studies on the complex microbial communites inhabiting vertebrate digestive systems, especially the ones that also explored the functional diversity of the microbial community (Bletz et al. 2016). This preprint by Scalvenzi et al. (2021) reports a comprehensive study on the phylogenetic and metabolic profiles of the Xenopus gut microbiota. The author describes significant changes in the gut microbiome communities at different developmental stages and demonstrates different microbial community composition across organs. In addition, the study also investigates the impact of diet on the Xenopus tadpole gut microbiome communities as well as how the bacterial communities are transmitted from parents to the next generation. This is one of the first studies that addresses the interactions between gut bacteria and tadpoles during the development. The authors observe the dynamics of gut microbiome communities during tadpole growth and metamorphosis. They also explore host-gut microbial community metabolic interactions and demostrate the capacity of the microbiome to complement the metabolic pathways of the Xenopus genome. Although this study is limited by the use of Xenopus tadpoles in a laboratory, which are probably different from those in nature, I believe it still provides important and valuable information for the research community working on vertebrate’s microbiota and their interaction with the host. References Bletz et al. (2016). Amphibian gut microbiota shifts differentially in community structure but converges on habitat-specific predicted functions. Nature Communications, 7(1), 1-12. doi: https://doi.org/10.1038/ncomms13699 Jandhyala, S. M., Talukdar, R., Subramanyam, C., Vuyyuru, H., Sasikala, M., & Reddy, D. N. (2015). Role of the normal gut microbiota. World journal of gastroenterology: WJG, 21(29), 8787. doi: https://dx.doi.org/10.3748%2Fwjg.v21.i29.8787 Scalvenzi, T., Clavereau, I., Bourge, M. & Pollet, N. (2021) Gut microbial ecology of Xenopus tadpoles across life stages. bioRxiv, 2020.05.25.110734, ver. 4 peer-reviewed and recommended by Peer community in Geonmics. https://doi.org/10.1101/2020.05.25.110734 | Gut microbial ecology of Xenopus tadpoles across life stages | Thibault Scalvenzi, Isabelle Clavereau, Mickael Bourge, Nicolas Pollet | <p><strong>Background</strong> The microorganism world living in amphibians is still largely under-represented and under-studied in the literature. Among anuran amphibians, African clawed frogs of the Xenopus genus stand as well-characterized mode... | ![]() | Evolutionary genomics, Metagenomics, Vertebrates | Wirulda Pootakham | 2020-05-25 14:01:19 | View | |
06 Aug 2024
![]() Identification and quantification of transposable element transcripts using Long-Read RNA-seq in Drosophila germline tissuesRita Rebollo, Pierre Gerenton, Eric Cumunel, Arnaud Mary, François Sabot, Nelly Burlet, Benjamin Gillet, Sandrine Hughes, Daniel Siqueira Oliveira, Clément Goubert, Marie Fablet, Cristina Vieira, Vincent Lacroix https://doi.org/10.1101/2023.05.27.542554Unveiling transposon dynamics: Advancing TE expression analysis in Drosophila with long-read sequencingRecommended by Nicolas Pollet based on reviews by Silke Jensen, Christophe Antoniewski and 1 anonymous reviewerTransposable elements (TEs) are mobile genetic elements with an intrinsic mutagenic potential that influences the physiology of any cell type, whether somatic or germinal. Measuring TE expression is a fundamental prerequisite for analysing the processes leading to the activity of TE-derived sequences. This applies to both old and recent TEs, as even if they are deficient in mobilisation, transcription of TE sequences alone can impact neighbouring gene expression and other cellular activities. In terms of TE physiology, transcription is crucial for mobilisation activity. The transcription of some TEs can be tissue-specific and associated with splicing events, as exemplified by the P-element isoforms in the fruit fly (Laski et al. 1986). Regarding host cell physiology, TE transcripts can include nearby exons, with or without splicing, and such chimeric transcripts can significantly alter gene activity. Thus, quantitative and qualitative analyses must be conducted to assess TE function and how they can modify genomic activities. Yet, due to the polymorphic, interspersed, and repetitive nature of TE sequences, the quantitative and qualitative analysis of TE transcript levels using short-read sequencing remains challenging (Lanciano and Cristofari 2020). In this context, Rebollo et al. (2024) employed nanopore long-read sequencing to analyse cDNAs derived from Drosophila melanogaster germline RNAs. The authors constructed two long-read cDNA libraries from pooled ovaries and testes using a protocol to obtain full-length cDNAs and sequenced them separately. They carefully compared their results with their short-read datasets. Overall, their observations corroborate known patterns of germline-specific expression of certain TEs and provide initial evidence of novel spliced TE transcript isoforms in Drosophila. Rebollo and colleagues have provided a well-documented and detailed analysis of their results, which will undoubtedly benefit the scientific community. They presented the challenges and limitations of their approach, such as the length of the transcripts, and provided a reproducible analysis workflow that will enable better characterisation of TE expression using long-read technology. Despite the small number of samples and limited sequencing depth, this pioneering study strikingly demonstrates the potential of long-read sequencing for the quantitative and qualitative analysis of TE transcription, a technology that will facilitate a better understanding of the transposon landscape. Lanciano S, Cristofari G (2020) Measuring and interpreting transposable element expression. Nature Reviews Genetics, 21, 721–736. https://doi.org/10.1038/s41576-020-0251-y Laski FA, Rio DC, Rubin GM (1986) Tissue specificity of Drosophila P element transposition is regulated at the level of mRNA splicing. Cell, 44, 7–19. https://doi.org/10.1016/0092-8674(86)90480-0 Rebollo R, Gerenton P, Cumunel E, Mary A, Sabot F, Burlet N, Gillet B, Hughes S, Oliveira DS, Goubert C, Fablet M, Vieira C, Lacroix V (2024) Identification and quantification of transposable element transcripts using Long-Read RNA-seq in Drosophila germline tissues. bioRxiv, ver.4 peer-reviewed and recommended by PCI Genomics. https://doi.org/10.1101/2023.05.27.542554 | Identification and quantification of transposable element transcripts using Long-Read RNA-seq in Drosophila germline tissues | Rita Rebollo, Pierre Gerenton, Eric Cumunel, Arnaud Mary, François Sabot, Nelly Burlet, Benjamin Gillet, Sandrine Hughes, Daniel Siqueira Oliveira, Clément Goubert, Marie Fablet, Cristina Vieira, Vincent Lacroix | <p>Transposable elements (TEs) are repeated DNA sequences potentially able to move throughout the genome. In addition to their inherent mutagenic effects, TEs can disrupt nearby genes by donating their intrinsic regulatory sequences, for instance,... | ![]() | Arthropods, Bioinformatics, Viruses and transposable elements | Nicolas Pollet | 2023-06-13 14:46:20 | View | |
07 Aug 2023
![]() Genomic data suggest parallel dental vestigialization within the xenarthran radiationChristopher A Emerling, Gillian C Gibb, Marie-Ka Tilak, Jonathan J Hughes, Melanie Kuch, Ana T Duggan, Hendrik N Poinar, Michael W Nachman, Frederic Delsuc https://doi.org/10.1101/2022.12.09.519446What does dental gene decay tell us about the regressive evolution of teeth in South American mammals?Recommended by Didier Casane based on reviews by Juan C. Opazo, Régis Debruyne and Nicolas PolletA group of mammals, Xenathra, evolved and diversified in South America during its long period of isolation in the early to mid Cenozoic era. More recently, as a result of the Great Faunal Interchange between South America and North America, many xenarthran species went extinct. The thirty-one extant species belong to three groups: armadillos, sloths and anteaters. They share dental degeneration. However, the level of degeneration is variable. Anteaters entirely lack teeth, sloths have intermediately regressed teeth and most armadillos have a toothless premaxilla, as well as peg-like, single-rooted teeth that lack enamel in adult animals (Vizcaíno 2009). This diversity raises a number of questions about the evolution of dentition in these mammals. Unfortunately, the fossil record is too poor to provide refined information on the different stages of regressive evolution in these clades. In such cases, the identification of loss-of-function mutations and/or relaxed selection in genes related to a character regression can be very informative (Emerling and Springer 2014; Meredith et al. 2014; Policarpo et al. 2021). Indeed, shared and unique pseudogenes/relaxed selection can tell us to what extent regression has occurred in common ancestors and whether some changes are lineage-specific. In addition, the distribution of pseudogenes/relaxed selection on the branches of a phylogenetic tree is related to the evolutionary processes involved. A much higher density of pseudogenes in the most internal branches indicates that degeneration took place early and over a short period of time, consistent with selection against the presence of the morphological character with which they are associated, while pseudogenes distributed evenly in many internal and external branches suggest a more gradual process over many millions of years, in line with relaxed selection and fixation of loss-of-function mutations by genetic drift. In this paper (Emerling et al. 2023), the authors examined the dynamics of decay of 11 dental genes that may parallel teeth regression. The analyses of the data reported in this paper clearly point to xenarthran teeth having repeatedly regressed in parallel in the three clades. In fact, no loss-of-function mutation is shared by all species examined. However, more genes should be studied to confirm the hypothesis that the common ancestor of extant xenarthrans had normal dentition. There are distinct patterns of gene loss in different lineages that are associated with the variation in dentition observed across the clades. These patterns of gene loss suggest that regressive evolution took place both gradually and in relatively rapid, discrete phases during the diversification of xenarthrans. This study underscores the utility of using pseudogenes to reconstruct evolutionary history of morphological characters when fossils are sparse. References Emerling CA, Gibb GC, Tilak M-K, Hughes JJ, Kuch M, Duggan AT, Poinar HN, Nachman MW, Delsuc F. 2023. Genomic data suggest parallel dental vestigialization within the xenarthran radiation. bioRxiv, 2022.12.09.519446, ver 2, peer-reviewed and recommended by PCI Genomics. https://doi.org/10.1101/2022.12.09.519446 Emerling CA, Springer MS. 2014. Eyes underground: Regression of visual protein networks in subterranean mammals. Molecular Phylogenetics and Evolution 78: 260-270. https://doi.org/10.1016/j.ympev.2014.05.016 Meredith RW, Zhang G, Gilbert MTP, Jarvis ED, Springer MS. 2014. Evidence for a single loss of mineralized teeth in the common avian ancestor. Science 346: 1254390. https://doi.org/10.1126/science.1254390 Policarpo M, Fumey J, Lafargeas P, Naquin D, Thermes C, Naville M, Dechaud C, Volff J-N, Cabau C, Klopp C, et al. 2021. Contrasting gene decay in subterranean vertebrates: insights from cavefishes and fossorial mammals. Molecular Biology and Evolution 38: 589-605. https://doi.org/10.1093/molbev/msaa249 Vizcaíno SF. 2009. The teeth of the “toothless”: novelties and key innovations in the evolution of xenarthrans (Mammalia, Xenarthra). Paleobiology 35: 343-366. https://doi.org/10.1666/0094-8373-35.3.343 | Genomic data suggest parallel dental vestigialization within the xenarthran radiation | Christopher A Emerling, Gillian C Gibb, Marie-Ka Tilak, Jonathan J Hughes, Melanie Kuch, Ana T Duggan, Hendrik N Poinar, Michael W Nachman, Frederic Delsuc | <p style="text-align: justify;">The recent influx of genomic data has provided greater insights into the molecular basis for regressive evolution, or vestigialization, through gene loss and pseudogenization. As such, the analysis of gene degradati... | ![]() | Evolutionary genomics, Vertebrates | Didier Casane | 2022-12-12 16:01:57 | View | |
22 Nov 2023
![]() The slow evolving genome of the xenacoelomorph worm Xenoturbella bockiPhilipp H. Schiffer, Paschalis Natsidis, Daniel J. Leite, Helen Robertson, François Lapraz, Ferdinand Marlétaz, Bastian Fromm, Liam Baudry, Fraser Simpson, Eirik Høye, Anne-C. Zakrzewski, Paschalia Kapli, Katharina J. Hoff, Steven Mueller, Martial Marbouty, Heather Marlow, Richard R. Copley, Romain Koszul, Peter Sarkies, Maximilian J. Telford https://doi.org/10.1101/2022.06.24.497508Genomic idiosyncrasies of Xenoturbella bocki: morphologically simple yet genetically complexRecommended by Rosa FernandezXenoturbella is a genus of morphologically simple bilaterians inhabiting benthic environments. Until very recently, only one species was known from the genus, Xenoturbella bocki Westblad 1949 [1]. Less than a decade ago, five more species were discovered (X. churro, X. monstrosa, X. profunda, X. hollandorum [2] and X. japonica [3]). These enigmatic animals lack an anus, a coelom, reproductive organs, nephrocytes and a centralized nervous system [1]. The systematic classification of the genus has substantially changed in the last decades, with first being considered as its own phylum (Xenoturbellida) and then being clustered together with acoels and nemertodermatids into the phylum Xenacoelomorpha [4,5]. The phylogenetic position of the xenacoelomorphs has been recalcitrant to resolution, with its position ranging from being the sister group to Nephrozoa (ie, protostomes and deuterostomes [6]) to the sister group to Ambulacraria (ie, Hemichordata and Echinodermata) in a clade called Xenambulacraria [4]. Recent studies based on expanded datasets and more refined analyses support either topology [7,8]. Either way, it is clear that additional studies on Xenoturbella could provide important insights into the origins of bilaterian traits such as the anus, the nephrons and the evolution of a centralized nervous system.
In any case, we are approaching a qualitative jump in how we understand phylogenomics thanks to efforts derived from the availability of chromosome-level genome assemblies for a growing number of species. Exciting times are ahead for us, evolutionary biologists, to explore what high-quality genomes - in combination with multiomics datasets - will reveal about animal evolution. I am personally really looking forward to it. References 1. Westblad E. (1949). Xenoturbella bocki n.g., n.sp., a peculiar, primitive Turbellarian type. Arkiv för Zoologi 1, 3-29 (1949). 2. Rouse, G. W., Wilson, N. G., Carvajal, J. I. & Vrijenhoek, R. C. New deep-sea species of Xenoturbella and the position of Xenacoelomorpha. Nature 530, 94–97 (2016). https://doi.org/10.1038/nature16545 3. Nakano, H. et al. Correction to: A new species of Xenoturbella from the western Pacific Ocean and the evolution of Xenoturbella. BMC Evol. Biol. 18, 1–2 (2018). https://doi.org/10.1186/s12862-018-1190-5 4. Philippe, H. et al. Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature 470, 255–258 (2011). https://doi.org/10.1038/nature09676 5. Hejnol, A. et al. Assessing the root of bilaterian animals with scalable phylogenomic methods. Proc. Biol. Sci. 276, 4261–4270 (2009). https://doi.org/10.1098/rspb.2009.0896 6. Cannon, J. T. et al. Xenacoelomorpha is the sister group to Nephrozoa. Nature 530, 89–93 (2016). https://doi.org/10.1038/nature16520 7. Laumer, C. E. et al. Revisiting metazoan phylogeny with genomic sampling of all phyla. Proc. Biol. Sci. 286, 20190831 (2019). https://doi.org/10.1098/rspb.2019.0831 8. Philippe, H. et al. Mitigating anticipated effects of systematic errors supports sister-group relationship between Xenacoelomorpha and Ambulacraria. Curr. Biol. 29, 1818–1826.e6 (2019). https://doi.org/10.1016/j.cub.2019.04.009 9. Schiffer, P. H., Natsidis, P., Leite D. J., Robertson, H., Lapraz, F., Marlétaz, F., Fromm, B., Baudry, L., Simpson, F., Høye, E., Zakrzewski, A-C., Kapli, P., Hoff, K. J., Mueller, S., Marbouty, M., Marlow, H., Copley, R. R., Koszul, R., Sarkies, P. & Telford, M .J. The slow evolving genome of the xenacoelomorph worm Xenoturbella bocki. bioRxiv (2023), ver. 4 peer-reviewed and recommended by Peer Community in Genomics. https://doi.org/10.1101/2022.06.24.497508 10. Suga, H. et al. The Capsaspora genome reveals a complex unicellular prehistory of animals. Nat. Commun. 4, 2325 (2013). https://doi.org/10.1038/ncomms3325 11. Fernández, R. & Gabaldón, T. Gene gain and loss across the metazoan tree of life. Nat Ecol Evol 4, 524–533 (2020). https://doi.org/10.1038/s41559-019-1069-x | The slow evolving genome of the xenacoelomorph worm *Xenoturbella bocki* | Philipp H. Schiffer, Paschalis Natsidis, Daniel J. Leite, Helen Robertson, François Lapraz, Ferdinand Marlétaz, Bastian Fromm, Liam Baudry, Fraser Simpson, Eirik Høye, Anne-C. Zakrzewski, Paschalia Kapli, Katharina J. Hoff, Steven Mueller, Martial... | <p style="text-align: justify;">The evolutionary origins of Bilateria remain enigmatic. One of the more enduring proposals highlights similarities between a cnidarian-like planula larva and simple acoel-like flatworms. This idea is based in part o... | ![]() | Evolutionary genomics | Rosa Fernandez | 2022-11-01 12:31:53 | View | |
06 Jul 2021
![]() A pipeline to detect the relationship between transposable elements and adjacent genes in host genomesCaroline Meguerditchian, Ayse Ergun, Veronique Decroocq, Marie Lefebvre, Quynh-Trang Bui https://doi.org/10.1101/2021.02.25.432867A new tool to cross and analyze TE and gene annotationsRecommended by Emmanuelle LeratTransposable elements (TEs) are important components of genomes. Indeed, they are now recognized as having a major role in gene and genome evolution (Biémont 2010). In particular, several examples have shown that the presence of TEs near genes may influence their functioning, either by recruiting particular epigenetic modifications (Guio et al. 2018) or by directly providing new regulatory sequences allowing new expression patterns (Chung et al. 2007; Sundaram et al. 2014). Therefore, the study of the interaction between TEs and their host genome requires tools to easily cross-annotate both types of entities. In particular, one needs to be able to identify all TEs located in the close vicinity of genes or inside them. Such task may not always be obvious for many biologists, as it requires informatics knowledge to develop their own script codes. In their work, Meguerdichian et al. (2021) propose a command-line pipeline that takes as input the annotations of both genes and TEs for a given genome, then detects and reports the positional relationships between each TE insertion and their closest genes. The results are processed into an R script to provide tables displaying some statistics and graphs to visualize these relationships. This tool has the potential to be very useful for performing preliminary analyses before studying the impact of TEs on gene functioning, especially for biologists. Indeed, it makes it possible to identify genes close to TE insertions. These identified genes could then be specifically considered in order to study in more detail the link between the presence of TEs and their functioning. For example, the identification of TEs close to genes may allow to determine their potential role on gene expression. References Biémont C (2010). A brief history of the status of transposable elements: from junk DNA to major players in evolution. Genetics, 186, 1085–1093. https://doi.org/10.1534/genetics.110.124180 Chung H, Bogwitz MR, McCart C, Andrianopoulos A, ffrench-Constant RH, Batterham P, Daborn PJ (2007). Cis-regulatory elements in the Accord retrotransposon result in tissue-specific expression of the Drosophila melanogaster insecticide resistance gene Cyp6g1. Genetics, 175, 1071–1077. https://doi.org/10.1534/genetics.106.066597 Guio L, Vieira C, González J (2018). Stress affects the epigenetic marks added by natural transposable element insertions in Drosophila melanogaster. Scientific Reports, 8, 12197. https://doi.org/10.1038/s41598-018-30491-w Meguerditchian C, Ergun A, Decroocq V, Lefebvre M, Bui Q-T (2021). A pipeline to detect the relationship between transposable elements and adjacent genes in host genomes. bioRxiv, 2021.02.25.432867, ver. 4 peer-reviewed and recommended by Peer Community In Genomics. https://doi.org/10.1101/2021.02.25.432867 Sundaram V, Cheng Y, Ma Z, Li D, Xing X, Edge P, Snyder MP, Wang T (2014). Widespread contribution of transposable elements to the innovation of gene regulatory networks. Genome Research, 24, 1963–1976. https://doi.org/10.1101/gr.168872.113 | A pipeline to detect the relationship between transposable elements and adjacent genes in host genomes | Caroline Meguerditchian, Ayse Ergun, Veronique Decroocq, Marie Lefebvre, Quynh-Trang Bui | <p>Understanding the relationship between transposable elements (TEs) and their closest positional genes in the host genome is a key point to explore their potential role in genome evolution. Transposable elements can regulate and affect gene expr... | ![]() | Bioinformatics, Viruses and transposable elements | Emmanuelle Lerat | 2021-03-03 15:08:34 | View | |
08 Apr 2022
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Phylogenetics in the Genomic EraCéline Scornavacca, Frédéric Delsuc, Nicolas Galtier https://hal.inria.fr/PGE/“Phylogenetics in the Genomic Era” brings together experts in the field to present a comprehensive synthesisRecommended by Robert Waterhouse and Karen MeusemannE-book: Phylogenetics in the Genomic Era (Scornavacca et al. 2021) This book was not peer-reviewed by PCI Genomics. It has undergone an internal review by the editors. Accurate reconstructions of the relationships amongst species and the genes encoded in their genomes are an essential foundation for almost all evolutionary inferences emerging from downstream analyses. Molecular phylogenetics has developed as a field over many decades to build suites of models and methods to reconstruct reliable trees that explain, support, or refute such inferences. The genomic era has brought new challenges and opportunities to the field, opening up new areas of research and algorithm development to take advantage of the accumulating large-scale data. Such ‘big-data’ phylogenetics has come to be known as phylogenomics, which broadly aims to connect molecular and evolutionary biology research to address questions centred on relationships amongst taxa, mechanisms of molecular evolution, and the biological functions of genes and other genomic elements. This book brings together experts in the field to present a comprehensive synthesis of Phylogenetics in the Genomic Era, covering key conceptual and methodological aspects of how to build accurate phylogenies and how to apply them in molecular and evolutionary research. The paragraphs below briefly summarise the five constituent parts of the book, highlighting the key concepts, methods, and applications that each part addresses. Being organised in an accessible style, while presenting details to provide depth where necessary, and including guides describing real-world examples of major phylogenomic tools, this collection represents an invaluable resource, particularly for students and newcomers to the field of phylogenomics. Part 1: Phylogenetic analyses in the genomic era Modelling how sequences evolve is a fundamental cornerstone of phylogenetic reconstructions. This part of the book introduces the reader to phylogenetic inference methods and algorithmic optimisations in the contexts of Markov, Maximum Likelihood, and Bayesian models of sequence evolution. The main concepts and theoretical considerations are mapped out for probabilistic Markov models, efficient tree building with Maximum Likelihood methods, and the flexibility and robustness of Bayesian approaches. These are supported with practical examples of phylogenomic applications using the popular tools RAxML and PhyloBayes. By considering theoretical, algorithmic, and practical aspects, these chapters provide readers with a holistic overview of the challenges and recent advances in developing scalable phylogenetic analyses in the genomic era. Part 2: Data quality, model adequacy This part focuses on the importance of considering the appropriateness of the evolutionary models used and the accuracy of the underlying molecular and genomic data. Both these aspects can profoundly affect the results when applying current phylogenomic methods to make inferences about complex biological and evolutionary processes. A clear example is presented for methods for building multiple sequence alignments and subsequent filtering approaches that can greatly impact phylogeny inference. The importance of error detection in (meta)barcode sequencing data is also highlighted, with solutions offered by the MACSE_BARCODE pipeline for accurate taxonomic assignments. Orthology datasets are essential markers for phylogenomic inferences, but the overview of concepts and methods presented shows that they too face challenges with respect to model selection and data quality. Finally, an innovative approach using ancestral gene order reconstructions provides new perspectives on how to assess gene tree accuracy for phylogenomic analyses. By emphasising through examples the importance of using appropriate evolutionary models and assessing input data quality, these chapters alert readers to key limitations that the field as a whole strives to address. Part 3: Resolving phylogenomic conflicts Conflicting phylogenetic signals are commonplace and may derive from statistical or systematic bias. This part of the book addresses possible causes of conflict, discordance between gene trees and species trees and how processes that lead to such conflicts can be described by phylogenetic models. Furthermore, it provides an overview of various models and methods with examples in phylogenomics including their pros and cons. Outlined in detail is the multispecies coalescent model (MSC) and its applications in phylogenomics. An interesting aspect is that different phylogenetic signals leading to conflict are in fact a key source of information rather than a problem that can – and should – be used to point to events like introgression or hybridisation, highlighting possible future trends in this research area. Last but not least, this part of the book also addresses inferring species trees by concatenating single multiple sequence alignments (gene alignments) versus inferring the species tree based on ensembles of single gene trees pointing out advantages and disadvantages of both approaches. As an important take home message from these chapters, it is recommended to be flexible and identify the most appropriate approach for each dataset to be analysed since this may tremendously differ depending on the dataset, setting, taxa, and phylogenetic level addressed by the researcher. Part 4: Functional evolutionary genomics In this part of the book the focus shifts to functional considerations of phylogenomics approaches both in terms of molecular evolution and adaptation and with respect to gene expression. The utility of multi-species analysis is clearly presented in the context of annotating functional genomic elements through quantifying evolutionary constraint and protein-coding potential. An historical perspective on characterising rates of change highlights how phylogenomic datasets help to understand the modes of molecular evolution across the genome, over time, and between lineages. These are contextualised with respect to the specific aim of detecting signatures of adaptation from protein-coding DNA alignments using the example of the MutSelDP-ω∗ model. This is extended with the presentation of the generally rare case of adaptive sequence convergence, where consideration of appropriate models and knowledge of gene functions and phenotypic effects are needed. Constrained or relaxed, selection pressures on sequence or copy-number affect genomic elements in different ways, making the very concept of function difficult to pin down despite it being fundamental to relate the genome to the phenotype and organismal fitness. Here gene expression provides a measurable intermediate, for which the Expression Comparison tool from the Bgee suite allows exploration of expression patterns across multiple animal species taking into account anatomical homology. Overall, phylogenomics applications in functional evolutionary genomics build on a rich theoretical history from molecular analyses where integration with knowledge of gene functions is challenging but critical. Part 5: Phylogenomic applications Rather than attempting to review the full extent of applications linked to phylogenomics, this part of the book focuses on providing detailed specific insights into selected examples and methods concerning i) estimating divergence times, and ii) species delimitation in the era of ‘omics’ data. With respect to estimating divergence times, an exemplary overview is provided for fossil data recovered from geological records, either using fossil data as calibration points with an extant-species-inferred phylogeny, or using a fossilised birth-death process as a mechanistic model that accounts for lineage diversification. Included is a tutorial for a joint approach to infer phylogenies and estimate divergence times using the RevBayes software with various models implemented for different applications and datasets incorporating molecular and morphological data. An interesting excursion is outlined focusing on timescale estimates with respect to viral evolution introducing BEAGLE, a high-performance likelihood-calculation platform that can be used on multi-core systems. As a second major subject, species delimitation is addressed since currently the increasing amount of available genomic data enables extensive inferences, for instance about the degree of genetic isolation among species and ancient and recent introgression events. Describing the history of molecular species delimitation up to the current genomic era and presenting widely used computational methods incorporating single- and multi-locus genomic data, pros and cons are addressed. Finally, a proposal for a new method for delimiting species based on empirical criteria is outlined. In the closing chapter of this part of the book, BPP (Bayesian Markov chain Monte Carlo program) for analysing multi-locus sequence data under the multispecies coalescent (MSC) model with and without introgression is introduced, including a tutorial. These examples together provide accessible details on key conceptual and methodological aspects related to the application of phylogenetics in the genomic era. References Scornavacca C, Delsuc F, Galtier N (2021) Phylogenetics in the Genomic Era. https://hal.inria.fr/PGE/ | Phylogenetics in the Genomic Era | Céline Scornavacca, Frédéric Delsuc, Nicolas Galtier | <p style="text-align: justify;">Molecular phylogenetics was born in the middle of the 20th century, when the advent of protein and DNA sequencing offered a novel way to study the evolutionary relationships between living organisms. The first 50 ye... | ![]() | Bacteria and archaea, Bioinformatics, Evolutionary genomics, Functional genomics, Fungi, Plants, Population genomics, Vertebrates, Viruses and transposable elements | Robert Waterhouse | 2022-03-15 17:43:52 | View | |
15 Mar 2024
![]() Convergent origin and accelerated evolution of vesicle-associated RhoGAP proteins in two unrelated parasitoid waspsDominique Colinet, Fanny Cavigliasso, Matthieu Leobold, Appoline Pichon, Serge Urbach, Dominique Cazes, Marine Poullet, Maya Belghazi, Anne-Nathalie Volkoff, Jean-Michel Drezen, Jean-Luc Gatti, and Marylène Poirié https://doi.org/10.1101/2023.06.05.543686Using transcriptomics and proteomics to understand the expansion of a secreted poisonous armoury in parasitoid wasps genomesRecommended by Ignacio BravoParasitoid wasps lay their eggs inside another arthropod, whose body is physically consumed by the parasitoid larvae. Phylogenetic inference suggests that Parasitoida are monophyletic, and that this clade underwent a strong radiation shortly after branching off from the Apocrita stem, some 236 million years ago (Peters et al. 2017). The increase in taxonomic diversity during evolutionary radiations is usually concurrent with an increase in genetic/genomic diversity, and is often associated with an increase in phenotypic diversity. Gene (or genome) duplication provides the evolutionary potential for such increase of genomic diversity by neo/subfunctionalisation of one of the gene paralogs, and is often proposed to be related to evolutionary radiations (Ohno 1970; Francino 2005).
References
| Convergent origin and accelerated evolution of vesicle-associated RhoGAP proteins in two unrelated parasitoid wasps | Dominique Colinet, Fanny Cavigliasso, Matthieu Leobold, Appoline Pichon, Serge Urbach, Dominique Cazes, Marine Poullet, Maya Belghazi, Anne-Nathalie Volkoff, Jean-Michel Drezen, Jean-Luc Gatti, and Marylène Poirié | <p>Animal venoms and other protein-based secretions that perform a variety of functions, from predation to defense, are highly complex cocktails of bioactive compounds. Gene duplication, accompanied by modification of the expression and/or functio... | ![]() | Evolutionary genomics | Ignacio Bravo | 2023-06-12 11:08:31 | View | |
12 Jul 2022
![]() Chromosome-level genome assembly and annotation of two lineages of the ant Cataglyphis hispanica: steppingstones towards genomic studies of hybridogenesis and thermal adaptation in desert antsHugo Darras, Natalia de Souza Araujo, Lyam Baudry, Nadège Guiglielmoni, Pedro Lorite, Martial Marbouty, Fernando Rodriguez, Irina Arkhipova, Romain Koszul, Jean-François Flot, Serge Aron https://doi.org/10.1101/2022.01.07.475286A genomic resource for ants, and moreRecommended by Nadia Ponts based on reviews by Isabel Almudi and Nicolas NègreThe ant species Cataglyphis hispanica is remarkably well adapted to arid habitats of the Iberian Peninsula where two hybridogenetic lineages co-occur, i.e., queens mating with males from the other lineage produce only non-reproductive hybrid workers whereas reproductive males and females are produced by parthenogenesis (Lavanchy and Schwander, 2019). For these two reasons, the genomes of these lineages, Chis1 and Chis2, are potential gold mines to explore the genetic bases of thermal adaptation and the evolution of alternative reproductive modes. Nowadays, sequencing technology enables assembling all kinds of genomes provided genomic DNA can be extracted. More difficult to achieve is high-quality assemblies with just as high-quality annotations that are readily available to the community to be used and re-used at will (Byrne et al., 2019; Salzberg, 2019). The challenge was successfully completed by Darras and colleagues, the generated resource being fully available to the community, including scripts and command lines used to obtain the proposed results. The authors particularly describe that lineage Chis2 has 27 chromosomes, against 26 or 27 for lineage Chis1, with a Robertsonian translocation identified by chromosome conformation capture (Duan et al., 2010, 2012) in the two Queens sequenced. Transcript-supported gene annotation provided 11,290 high-quality gene models. In addition, an ant-tailored annotation pipeline identified 56 different families of repetitive elements in both Chis1 and Chis2 lineages of C. hispanica spread in a little over 15 % of the genome. Altogether, the genomes of Chis1 and Chis2 are highly similar and syntenic, with some level of polymorphism raising questions about their evolutionary story timeline. In particular, the uniform distribution of polymorphisms along the genomes shakes up a previous hypothesis of hybridogenetic lineage pairs determined by ancient non-recombining regions (Linksvayer, Busch and Smith, 2013). I recommend this paper because the science behind is both solid and well-explained. The provided resource is of high quality, and accompanied by a critical exploration of the perspectives brought by the results. These genomes are excellent resources to now go further in exploring the possible events at the genome level that accompanied the remarkable thermal adaptation of the ants Cataglyphis, as well as insights into the genetics of hybridogenetic lineages. Beyond the scientific value of the resources and insights provided by the work performed, I also recommend this article because it is an excellent example of Open Science (Allen and Mehler, 2019; Sarabipour et al., 2019), all data methods and tools being fully and easily accessible to whoever wants/needs it. References Allen C, Mehler DMA (2019) Open science challenges, benefits and tips in early career and beyond. PLOS Biology, 17, e3000246. https://doi.org/10.1371/journal.pbio.3000246 Byrne A, Cole C, Volden R, Vollmers C (2019) Realizing the potential of full-length transcriptome sequencing. Philosophical Transactions of the Royal Society B: Biological Sciences, 374, 20190097. https://doi.org/10.1098/rstb.2019.0097 Darras H, de Souza Araujo N, Baudry L, Guiglielmoni N, Lorite P, Marbouty M, Rodriguez F, Arkhipova I, Koszul R, Flot J-F, Aron S (2022) Chromosome-level genome assembly and annotation of two lineages of the ant Cataglyphis hispanica: stepping stones towards genomic studies of hybridogenesis and thermal adaptation in desert ants. bioRxiv, 2022.01.07.475286, ver. 3 peer-reviewed and recommended by Peer community in Genomics. https://doi.org/10.1101/2022.01.07.475286 Duan Z, Andronescu M, Schutz K, Lee C, Shendure J, Fields S, Noble WS, Anthony Blau C (2012) A genome-wide 3C-method for characterizing the three-dimensional architectures of genomes. Methods, 58, 277–288. https://doi.org/10.1016/j.ymeth.2012.06.018 Duan Z, Andronescu M, Schutz K, McIlwain S, Kim YJ, Lee C, Shendure J, Fields S, Blau CA, Noble WS (2010) A three-dimensional model of the yeast genome. Nature, 465, 363–367. https://doi.org/10.1038/nature08973 Lavanchy G, Schwander T (2019) Hybridogenesis. Current Biology, 29, R9–R11. https://doi.org/10.1016/j.cub.2018.11.046 Linksvayer TA, Busch JW, Smith CR (2013) Social supergenes of superorganisms: Do supergenes play important roles in social evolution? BioEssays, 35, 683–689. https://doi.org/10.1002/bies.201300038 Salzberg SL (2019) Next-generation genome annotation: we still struggle to get it right. Genome Biology, 20, 92. https://doi.org/10.1186/s13059-019-1715-2 Sarabipour S, Debat HJ, Emmott E, Burgess SJ, Schwessinger B, Hensel Z (2019) On the value of preprints: An early career researcher perspective. PLOS Biology, 17, e3000151. https://doi.org/10.1371/journal.pbio.3000151 | Chromosome-level genome assembly and annotation of two lineages of the ant Cataglyphis hispanica: steppingstones towards genomic studies of hybridogenesis and thermal adaptation in desert ants | Hugo Darras, Natalia de Souza Araujo, Lyam Baudry, Nadège Guiglielmoni, Pedro Lorite, Martial Marbouty, Fernando Rodriguez, Irina Arkhipova, Romain Koszul, Jean-François Flot, Serge Aron | <p style="text-align: justify;"><em>Cataglyphis</em> are thermophilic ants that forage during the day when temperatures are highest and sometimes close to their critical thermal limit. Several Cataglyphis species have evolved unusual reproductive ... | ![]() | Evolutionary genomics | Nadia Ponts | Nicolas Nègre, Isabel Almudi | 2022-01-13 16:47:30 | View |
22 Oct 2024
![]() Chromosome level genome reference of the Caucasian dwarf goby Knipowitschia cf. caucasica, a new alien Gobiidae invading the River RhineAlexandra Schoenle, Nadège Guiglielmoni, Tobias Mainz, Carola Greve, Alexander B. Hamadou, Lisa Heermann, Jost Borcherding, Ann-Marie Waldvogel https://doi.org/10.1101/2024.04.22.590508New chromosome-scale genome assembly for the Dwarf Goby, a River Rhine invaderRecommended by Iker IrisarriSince the opening of the Rhine-Main-Danube-Channel, four goby species are known to have invaded the River Rhine. Of these, the most recent and numerous is the Caucasian Dwarf Goby, which has been found in the Rhine since 2019. This study presents a new high-quality genome for this species (Knipowitschia cf. caucasica) (Schoenle et al. 2024). Currently, chromosome-scale genome assemblies represent a key first step in invasion biology, allowing the reconstruction of a species’ invasion history and monitoring its progress, as well as identifying and characterizing candidate genes that control invasiveness (McCartney et al. 2019). The authors sequenced the nuclear and mitochondrial genomes of this species using state-of-the art methods including long-read sequencing techniques, scaffolded based on chromatin conformation data, and annotated using both direct transcriptomic and protein homology evidence. Data analyses follow currently established pipelines for genome assembly, scaffolding, annotation, and downstream bioinformatic analyses. The quality of the final genome was thoroughly assessed and conforms to what is expected from other genomes of fishes in the family Gobiidae. This study follows other recent endeavors that generated high-quality genomes to improve our understanding of invasion biology (e.g. Shao et al. 2020 and Kitsoulis et al. 2023). These studies are successfully contributing to increasing the genomic resources for the world’s most damaging invasive species, which were not available for even a third of the top 100 invasive species just five years ago (McCarthy et al. 2019). Beyond invasion biology, the Dwarf Goby genome is also an important resource for many other applications, including evolutionary genomic analyses and phylogeography of this species and closely related ones in their native ranges. Kitsoulis CV, Papadogiannis V, Kristoffersen JB, Kaitetzidou E, Sterioti A, Tsigenopoulos CS, Manousaki T (2023) Near-chromosome level genome assembly of devil firefish, Pterois miles. Peer Community Journal 3:e64. https://doi.org/10.24072/pcjournal.295 McCartney MA, Mallez S, Gohl DM (2019) Genome projects in invasion biology. Conservation Genetics 20:1201–1222. https://doi.org/10.1007/s10592-019-01224-x Schoenle A, Guiglielmoni N, Mainz T, Greve C, Hamadou AB, Heermann L, Borcherding J, Waldvogel A-M (2024) Chromosome level genome reference of the Caucasian dwarf goby Knipowitschia cf. caucasica, a new alien Gobiidae invading the River Rhine. bioRxiv, ver. 3 peer-reviewed and recommended by PCI Genomics. https://doi.org/10.1101/2024.04.22.590508 Shao F, Ludwig A, Mao Y, Liu N, Peng Z (2020). Chromosome-level genome assembly of the female western mosquitofish (Gambusia affinis). GigaScience 9:giaa092. https://doi.org/10.1093/gigascience/giaa092
| Chromosome level genome reference of the Caucasian dwarf goby *Knipowitschia* cf. *caucasica*, a new alien Gobiidae invading the River Rhine | Alexandra Schoenle, Nadège Guiglielmoni, Tobias Mainz, Carola Greve, Alexander B. Hamadou, Lisa Heermann, Jost Borcherding, Ann-Marie Waldvogel | <p>The Caucasian dwarf goby <em>Knipowitschia</em> cf. <em>caucasica</em> is a new invasive alien Gobiidae spreading in the Lower Rhine since 2019. Little is known about the invasion biology of the species and further investigations to reconstruct... | ![]() | ERGA, Vertebrates | Iker Irisarri | 2024-04-29 17:52:25 | View | |
26 Jun 2024
![]() Transposable element expression with variation in sex chromosome number supports a toxic Y effect on human longevityJordan Teoli, Miriam Merenciano, Marie Fablet, Anamaria Necsulea, Daniel Siqueira-de-Oliveira, Alessandro Brandulas-Cammarata, Audrey Labalme, Hervé Lejeune, Jean-François Lemaitre, François Gueyffier, Damien Sanlaville, Claire Bardel, Cristina Vieira, Gabriel AB Marais, Ingrid Plotton https://doi.org/10.1101/2023.08.03.550779The number of Y chromosomes is positively associated with transposable element expression in humans, in line with the toxic Y hypothesisRecommended by Anna-Sophie Fiston-LavierThe study of human longevity has long been a source of fascination for scientists, particularly in relation to the genetic factors that contribute to differences in lifespan between the sexes. One particularly intriguing area of research concerns the Y chromosome and its impact on male longevity. The Y chromosome expresses genes that are essential for male development and reproduction. However, it may also influence various physiological processes and health outcomes. It is therefore of great importance to investigate the impact of the Y chromosome on longevity. This may assist in elucidating the biological mechanisms underlying sex-specific differences in aging and disease susceptibility. As longevity research progresses, the Y chromosome's role presents a promising avenue for elucidating the complex interplay between genetics and aging. Transposable elements (TEs), often referred to as "jumping genes", are DNA sequences that can move within the genome, potentially causing mutations and genomic instability. In young, healthy cells, various mechanisms, including DNA methylation and histone modifications, suppress TE activity to maintain genomic integrity. However, as individuals age, these regulatory mechanisms may deteriorate, leading to increased TE activity. This dysregulation could contribute to age-related genomic instability, cellular dysfunction, and the onset of diseases such as cancer. Understanding how TE repression changes with age is crucial for uncovering the molecular underpinnings of aging (De Cecco et al. 2013; Van Meter et al. 2014). The lower recombination rates observed on Y chromosomes result in the accumulation of TE insertions, which in turn leads to an enrichment of TEs and potentially higher TE activity. To ascertain whether the number of Y chromosomes is associated with TE activity in humans, Teoli et al. (2024) studied the TE expression level, as a proxy of the TE activity, in several karyotype compositions (i.e. with differing numbers of Y chromosomes). They used transcriptomic data from blood samples collected in 24 individuals (six females 46,XX, six males 46,XY, eight males 47,XXY and four males 47,XYY). Even though they did not observe a significant correlation between the number of Y chromosomes and TE expression, their results suggest an impact of the presence of the Y chromosome on the overall TE expression. The presence of Y chromosomes also affected the type (family) of TE present/expressed. To ensure that the TE expression level was not biased by the expression of a gene in proximity due to intron retention or pervasive intragenic transcription, the authors also tested whether the TE expression variation observed between the different karyotypes could be explained by gene (i.e. here non-TE gene) expression. As TE repression mechanisms are known to decrease over time, the authors also tested whether TE repression is weaker in older individuals, which would support a compelling link between genomic stability and aging. They investigated the TE expression differently between males and females, hypothesizing that old males should exhibit a stronger TE activity than old females. Using selected 45 males (47,XY) and 35 females (46,XX) blood samples of various ages (from 20 to 70) from the Genotype-Tissue Expression (GTEx) project, the authors studied the effect of age on TE expression using 10-year range to group the study subjects. Based on these data, they fail to find an overall increase of TE expression in old males compared to old females. Notwithstanding the small number of samples, the study is well-designed and innovative, and its findings are highly promising. It marks an initial step towards understanding the impact of Y-chromosome ‘toxicity’ on human longevity. Despite the relatively small sample size, which is a consequence of the difficulty of obtaining samples from individuals with sex chromosome aneuploidies, the results are highly intriguing and will be of interest to a broad range of biologists.
References De Cecco M, Criscione SW, Peckham EJ, Hillenmeyer S, Hamm EA, Manivannan J, Peterson AL, Kreiling JA, Neretti N, Sedivy JM (2013) Genomes of replicatively senescent cells undergo global epigenetic changes leading to gene silencing and activation of transposable elements. Aging Cell, 12, 247–256. https://doi.org/10.1111/acel.12047 Teoli J, Merenciano M, Fablet M, Necsulea A, Siqueira-de-Oliveira D, Brandulas-Cammarata A, Labalme A, Lejeune H, Lemaitre J-F, Gueyffier F, Sanlaville D, Bardel C, Vieira C, Marais GAB, Plotton I (2024) Transposable element expression with variation in sex chromosome number supports a toxic Y effect on human longevity. bioRxiv, ver. 5 peer-reviewed and recommended by Peer Community in Genomics. https://doi.org/10.1101/2023.08.03.550779 Van Meter M, Kashyap M, Rezazadeh S, Geneva AJ, Morello TD, Seluanov A, Gorbunova V (2014) SIRT6 represses LINE1 retrotransposons by ribosylating KAP1 but this repression fails with stress and age. Nature Communications, 5, 5011. https://doi.org/10.1038/ncomms6011
| Transposable element expression with variation in sex chromosome number supports a toxic Y effect on human longevity | Jordan Teoli, Miriam Merenciano, Marie Fablet, Anamaria Necsulea, Daniel Siqueira-de-Oliveira, Alessandro Brandulas-Cammarata, Audrey Labalme, Hervé Lejeune, Jean-François Lemaitre, François Gueyffier, Damien Sanlaville, Claire Bardel, Cristina Vi... | <p>Why women live longer than men is still an open question in human biology. Sex chromosomes have been proposed to play a role in the observed sex gap in longevity, and the Y male chromosome has been suspected of having a potential toxic genomic ... | ![]() | Evolutionary genomics | Anna-Sophie Fiston-Lavier | Anonymous, Igor Rogozin , Paul Jay , Anonymous | 2023-08-18 15:01:38 | View |
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