21 results on '"McGregor, Alistair"'
Search Results
2. Gene content evolution in the arthropods
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Thomas, Gregg WC, Dohmen, Elias, Hughes, Daniel ST, Murali, Shwetha C, Poelchau, Monica, Glastad, Karl, Anstead, Clare A, Ayoub, Nadia A, Batterham, Phillip, Bellair, Michelle, Binford, Greta J, Chao, Hsu, Chen, Yolanda H, Childers, Christopher, Dinh, Huyen, Doddapaneni, Harsha Vardhan, Duan, Jian J, Dugan, Shannon, Esposito, Lauren A, Friedrich, Markus, Garb, Jessica, Gasser, Robin B, Goodisman, Michael AD, Gundersen-Rindal, Dawn E, Han, Yi, Handler, Alfred M, Hatakeyama, Masatsugu, Hering, Lars, Hunter, Wayne B, Ioannidis, Panagiotis, Jayaseelan, Joy C, Kalra, Divya, Khila, Abderrahman, Korhonen, Pasi K, Lee, Carol Eunmi, Lee, Sandra L, Li, Yiyuan, Lindsey, Amelia RI, Mayer, Georg, McGregor, Alistair P, McKenna, Duane D, Misof, Bernhard, Munidasa, Mala, Munoz-Torres, Monica, Muzny, Donna M, Niehuis, Oliver, Osuji-Lacy, Nkechinyere, Palli, Subba R, Panfilio, Kristen A, Pechmann, Matthias, Perry, Trent, Peters, Ralph S, Poynton, Helen C, Prpic, Nikola-Michael, Qu, Jiaxin, Rotenberg, Dorith, Schal, Coby, Schoville, Sean D, Scully, Erin D, Skinner, Evette, Sloan, Daniel B, Stouthamer, Richard, Strand, Michael R, Szucsich, Nikolaus U, Wijeratne, Asela, Young, Neil D, Zattara, Eduardo E, Benoit, Joshua B, Zdobnov, Evgeny M, Pfrender, Michael E, Hackett, Kevin J, Werren, John H, Worley, Kim C, Gibbs, Richard A, Chipman, Ariel D, Waterhouse, Robert M, Bornberg-Bauer, Erich, Hahn, Matthew W, and Richards, Stephen
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Human Genome ,Genetics ,Biotechnology ,Generic health relevance ,Animals ,Arthropods ,DNA Methylation ,Evolution ,Molecular ,Genetic Speciation ,Genetic Variation ,Phylogeny ,Genome assembly ,Genomics ,Protein domains ,Gene content ,Evolution ,DNA methylation ,Environmental Sciences ,Biological Sciences ,Information and Computing Sciences ,Bioinformatics - Abstract
BackgroundArthropods comprise the largest and most diverse phylum on Earth and play vital roles in nearly every ecosystem. Their diversity stems in part from variations on a conserved body plan, resulting from and recorded in adaptive changes in the genome. Dissection of the genomic record of sequence change enables broad questions regarding genome evolution to be addressed, even across hyper-diverse taxa within arthropods.ResultsUsing 76 whole genome sequences representing 21 orders spanning more than 500 million years of arthropod evolution, we document changes in gene and protein domain content and provide temporal and phylogenetic context for interpreting these innovations. We identify many novel gene families that arose early in the evolution of arthropods and during the diversification of insects into modern orders. We reveal unexpected variation in patterns of DNA methylation across arthropods and examples of gene family and protein domain evolution coincident with the appearance of notable phenotypic and physiological adaptations such as flight, metamorphosis, sociality, and chemoperception.ConclusionsThese analyses demonstrate how large-scale comparative genomics can provide broad new insights into the genotype to phenotype map and generate testable hypotheses about the evolution of animal diversity.
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- 2020
3. The house spider genome reveals an ancient whole-genome duplication during arachnid evolution
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Schwager, Evelyn E, Sharma, Prashant P, Clarke, Thomas, Leite, Daniel J, Wierschin, Torsten, Pechmann, Matthias, Akiyama-Oda, Yasuko, Esposito, Lauren, Bechsgaard, Jesper, Bilde, Trine, Buffry, Alexandra D, Chao, Hsu, Dinh, Huyen, Doddapaneni, HarshaVardhan, Dugan, Shannon, Eibner, Cornelius, Extavour, Cassandra G, Funch, Peter, Garb, Jessica, Gonzalez, Luis B, Gonzalez, Vanessa L, Griffiths-Jones, Sam, Han, Yi, Hayashi, Cheryl, Hilbrant, Maarten, Hughes, Daniel ST, Janssen, Ralf, Lee, Sandra L, Maeso, Ignacio, Murali, Shwetha C, Muzny, Donna M, Nunes da Fonseca, Rodrigo, Paese, Christian LB, Qu, Jiaxin, Ronshaugen, Matthew, Schomburg, Christoph, Schönauer, Anna, Stollewerk, Angelika, Torres-Oliva, Montserrat, Turetzek, Natascha, Vanthournout, Bram, Werren, John H, Wolff, Carsten, Worley, Kim C, Bucher, Gregor, Gibbs, Richard A, Coddington, Jonathan, Oda, Hiroki, Stanke, Mario, Ayoub, Nadia A, Prpic, Nikola-Michael, Flot, Jean-François, Posnien, Nico, Richards, Stephen, and McGregor, Alistair P
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Human Genome ,Genetics ,Generic health relevance ,Animals ,Evolution ,Molecular ,Female ,Gene Duplication ,Genome ,Male ,Spiders ,Synteny ,Parasteatoda tepidariorum ,Centruroides sculpturatus ,Gene duplication ,Evolution ,Hox genes ,Developmental Biology - Abstract
BackgroundThe duplication of genes can occur through various mechanisms and is thought to make a major contribution to the evolutionary diversification of organisms. There is increasing evidence for a large-scale duplication of genes in some chelicerate lineages including two rounds of whole genome duplication (WGD) in horseshoe crabs. To investigate this further, we sequenced and analyzed the genome of the common house spider Parasteatoda tepidariorum.ResultsWe found pervasive duplication of both coding and non-coding genes in this spider, including two clusters of Hox genes. Analysis of synteny conservation across the P. tepidariorum genome suggests that there has been an ancient WGD in spiders. Comparison with the genomes of other chelicerates, including that of the newly sequenced bark scorpion Centruroides sculpturatus, suggests that this event occurred in the common ancestor of spiders and scorpions, and is probably independent of the WGDs in horseshoe crabs. Furthermore, characterization of the sequence and expression of the Hox paralogs in P. tepidariorum suggests that many have been subject to neo-functionalization and/or sub-functionalization since their duplication.ConclusionsOur results reveal that spiders and scorpions are likely the descendants of a polyploid ancestor that lived more than 450 MYA. Given the extensive morphological diversity and ecological adaptations found among these animals, rivaling those of vertebrates, our study of the ancient WGD event in Arachnopulmonata provides a new comparative platform to explore common and divergent evolutionary outcomes of polyploidization events across eukaryotes.
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- 2017
4. Looking across the gap: Understanding the evolution of eyes and vision among insects.
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Kittelmann, Maike and McGregor, Alistair P.
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POLLINATORS , *INSECTS , *BEES , *OPTICAL information processing , *BUTTERFLIES , *VISUAL accommodation , *VISION - Abstract
The compound eyes of insects exhibit stunning variation in size, structure, and function, which has allowed these animals to use their vision to adapt to a huge range of different environments and lifestyles, and evolve complex behaviors. Much of our knowledge of eye development has been learned from Drosophila, while visual adaptations and behaviors are often more striking and better understood from studies of other insects. However, recent studies in Drosophila and other insects, including bees, beetles, and butterflies, have begun to address this gap by revealing the genetic and developmental bases of differences in eye morphology and key new aspects of compound eye structure and function. Furthermore, technical advances have facilitated the generation of high‐resolution connectomic data from different insect species that enhances our understanding of visual information processing, and the impact of changes in these processes on the evolution of vision and behavior. Here, we review these recent breakthroughs and propose that future integrated research from the development to function of visual systems within and among insect species represents a great opportunity to understand the remarkable diversification of insect eyes and vision. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Pervasive microRNA Duplication in Chelicerates: Insights from the Embryonic microRNA Repertoire of the Spider Parasteatoda tepidariorum
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Leite, Daniel J, Ninova, Maria, Hilbrant, Maarten, Arif, Saad, Griffiths-Jones, Sam, Ronshaugen, Matthew, and McGregor, Alistair P
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Genetics ,Biotechnology ,Underpinning research ,1.1 Normal biological development and functioning ,Animals ,Conserved Sequence ,Drosophila melanogaster ,Evolution ,Molecular ,Gene Duplication ,MicroRNAs ,Spiders ,Parasteatoda tepidariorum ,spiders ,Cheliceratal ,microRNA ,gene duplication ,arm usage ,Biochemistry and Cell Biology ,Evolutionary Biology ,Developmental Biology - Abstract
MicroRNAs are small (∼22 nt) noncoding RNAs that repress translation and therefore regulate the production of proteins from specific target mRNAs. microRNAs have been found to function in diverse aspects of gene regulation within animal development and many other processes. Among invertebrates, both conserved and novel, lineage specific, microRNAs have been extensively studied predominantly in holometabolous insects such as Drosophila melanogaster However little is known about microRNA repertoires in other arthropod lineages such as the chelicerates. To understand the evolution of microRNAs in this poorly sampled subphylum, we characterized the microRNA repertoire expressed during embryogenesis of the common house spider Parasteatoda tepidariorum We identified a total of 148 microRNAs in P. tepidariorum representing 66 families. Approximately half of these microRNA families are conserved in other metazoans, while the remainder are specific to this spider. Of the 35 conserved microRNAs families 15 had at least two copies in the P. tepidariorum genome. A BLAST-based approach revealed a similar pattern of duplication in other spiders and a scorpion, but not among other chelicerates and arthropods, with the exception of a horseshoe crab. Among the duplicated microRNAs we found examples of lineage-specific tandem duplications, and the duplication of entire microRNA clusters in three spiders, a scorpion, and in a horseshoe crab. Furthermore, we found that paralogs of many P. tepidariorum microRNA families exhibit arm switching, which suggests that duplication was often followed by sub- or neofunctionalization. Our work shows that understanding the evolution of microRNAs in the chelicerates has great potential to provide insights into the process of microRNA duplication and divergence and the evolution of animal development.
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- 2016
6. Evolution of the Spider Homeobox Gene Repertoire by Tandem and Whole Genome Duplication.
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Aase-Remedios, Madeleine E, Janssen, Ralf, Leite, Daniel J, Sumner-Rooney, Lauren, and McGregor, Alistair P
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HOMEOBOX genes ,SPIDER venom ,GENE regulatory networks ,SPIDERS ,GENOMES ,CHROMOSOME duplication ,PARTITION functions - Abstract
Gene duplication generates new genetic material that can contribute to the evolution of gene regulatory networks and phenotypes. Duplicated genes can undergo subfunctionalization to partition ancestral functions and/or neofunctionalization to assume a new function. We previously found there had been a whole genome duplication (WGD) in an ancestor of arachnopulmonates, the lineage including spiders and scorpions but excluding other arachnids like mites, ticks, and harvestmen. This WGD was evidenced by many duplicated homeobox genes, including two Hox clusters, in spiders. However, it was unclear which homeobox paralogues originated by WGD versus smaller-scale events such as tandem duplications. Understanding this is a key to determining the contribution of the WGD to arachnopulmonate genome evolution. Here we characterized the distribution of duplicated homeobox genes across eight chromosome-level spider genomes. We found that most duplicated homeobox genes in spiders are consistent with an origin by WGD. We also found two copies of conserved homeobox gene clusters, including the Hox, NK, HRO, Irx , and SINE clusters, in all eight species. Consistently, we observed one copy of each cluster was degenerated in terms of gene content and organization while the other remained more intact. Focussing on the NK cluster, we found evidence for regulatory subfunctionalization between the duplicated NK genes in the spider Parasteatoda tepidariorum compared to their single-copy orthologues in the harvestman Phalangium opilio. Our study provides new insights into the relative contributions of multiple modes of duplication to the homeobox gene repertoire during the evolution of spiders and the function of NK genes. [ABSTRACT FROM AUTHOR]
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- 2023
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7. Duplication and expression of Sox genes in spiders
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Bonatto Paese, Christian L., Leite, Daniel J., Schönauer, Anna, McGregor, Alistair P., and Russell, Steven
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- 2018
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8. Duplication and expression of Sox genes in spiders
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Bonatto Paese, Christian L, Leite, Daniel J, Schönauer, Anna, McGregor, Alistair P, Russell, Steven, Russell, Steven [0000-0003-0546-3031], and Apollo - University of Cambridge Repository
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Genome ,Parasteatoda tepidariorum ,Evolution ,Organogenesis ,Stegodyphus mimosarum ,Embryonic Development ,Gene Expression Regulation, Developmental ,Spiders ,Development ,Evolution, Molecular ,Gene Duplication ,Sox genes ,QH359-425 ,Animals ,Spider ,Phylogeny ,SOX Transcription Factors ,Research Article - Abstract
Background The Sox family of transcription factors is an important part of the genetic ‘toolbox’ of all metazoans examined to date and is known to play important developmental roles in vertebrates and insects. However, outside the commonly studied Drosophila model little is known about the repertoire of Sox family transcription factors in other arthropod species. Here we characterise the Sox family in two chelicerate species, the spiders Parasteatoda tepidariorum and Stegodyphus mimosarum, which have experienced a whole genome duplication (WGD) in their evolutionary history. Results We find that virtually all of the duplicate Sox genes have been retained in these spiders after the WGD. Analysis of the expression of Sox genes in P. tepidariorum embryos suggests that it is likely that some of these genes have neofunctionalised after duplication. Our expression analysis also strengthens the view that an orthologue of vertebrate Group B1 genes, SoxNeuro, is implicated in the earliest events of CNS specification in both vertebrates and invertebrates. In addition, a gene in the Dichaete/Sox21b class is dynamically expressed in the spider segment addition zone, suggestive of an ancient regulatory mechanism controlling arthropod segmentation as recently suggested for flies and beetles. Together with the recent analysis of Sox gene expression in the embryos of other arthropods, our findings support the idea of conserved functions for some of these genes, including a potential role for SoxC and SoxD genes in CNS development and SoxF in limb development. Conclusions Our study provides a new chelicerate perspective to understanding the evolution and function of Sox genes and how the retention of duplicates of such important tool-box genes after WGD has contributed to different aspects of spider embryogenesis. Future characterisation of the function of these genes in spiders will help us to better understand the evolution of the regulation of important developmental processes in arthropods and other metazoans including neurogenesis and segmentation. Electronic supplementary material The online version of this article (10.1186/s12862-018-1337-4) contains supplementary material, which is available to authorized users.
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- 2018
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9. The Evolution of Sox Gene Repertoires and Regulation of Segmentation in Arachnids.
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Baudouin-Gonzalez, Luis, Schoenauer, Anna, Harper, Amber, Blakeley, Grace, Seiter, Michael, Arif, Saad, Sumner-Rooney, Lauren, Russell, Steven, Sharma, Prashant P, and McGregor, Alistair P
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METAZOA evolution ,BILATERIA ,ARACHNIDA ,ARTHROPODA ,GENETIC variation - Abstract
The Sox family of transcription factors regulates many processes during metazoan development, including stem cell maintenance and nervous system specification. Characterizing the repertoires and roles of these genes can therefore provide important insights into animal evolution and development. We further characterized the Sox repertoires of several arachnid species with and without an ancestral whole-genome duplication and compared their expression between the spider Parasteatoda tepidariorum and the harvestman Phalangium opilio. We found that most Sox families have been retained as ohnologs after whole-genome duplication and evidence for potential subfunctionalization and/or neofunctionalization events. Our results also suggest that Sox21b-1 likely regulated segmentation ancestrally in arachnids, playing a similar role to the closely related SoxB gene, Dichaete , in insects. We previously showed that Sox21b-1 is required for the simultaneous formation of prosomal segments and sequential addition of opisthosomal segments in P. tepidariorum. We studied the expression and function of Sox21b-1 further in this spider and found that although this gene regulates the generation of both prosomal and opisthosomal segments, it plays different roles in the formation of these tagmata reflecting their contrasting modes of segmentation and deployment of gene regulatory networks with different architectures. [ABSTRACT FROM AUTHOR]
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- 2021
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10. Conservation, loss, and redeployment of Wnt ligands in protostomes: implications for understanding the evolution of segment formation
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Kosiol Carolin, Prpic Nikola-Michael, Brown Susan J, Colbourne John K, Budd Graham E, Hopfen Corinna, Schwager Evelyn E, Bolognesi Renata, Poulin Francis, Pechmann Matthias, Le Gouar Martine, Janssen Ralf, Vervoort Michel, Damen Wim GM, Balavoine Guillaume, and McGregor Alistair P
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Evolution ,QH359-425 - Abstract
Abstract Background The Wnt genes encode secreted glycoprotein ligands that regulate a wide range of developmental processes, including axis elongation and segmentation. There are thirteen subfamilies of Wnt genes in metazoans and this gene diversity appeared early in animal evolution. The loss of Wnt subfamilies appears to be common in insects, but little is known about the Wnt repertoire in other arthropods, and moreover the expression and function of these genes have only been investigated in a few protostomes outside the relatively Wnt-poor model species Drosophila melanogaster and Caenorhabditis elegans. To investigate the evolution of this important gene family more broadly in protostomes, we surveyed the Wnt gene diversity in the crustacean Daphnia pulex, the chelicerates Ixodes scapularis and Achaearanea tepidariorum, the myriapod Glomeris marginata and the annelid Platynereis dumerilii. We also characterised Wnt gene expression in the latter three species, and further investigated expression of these genes in the beetle Tribolium castaneum. Results We found that Daphnia and Platynereis both contain twelve Wnt subfamilies demonstrating that the common ancestors of arthropods, ecdysozoans and protostomes possessed all members of all Wnt subfamilies except Wnt3. Furthermore, although there is striking loss of Wnt genes in insects, other arthropods have maintained greater Wnt gene diversity. The expression of many Wnt genes overlap in segmentally reiterated patterns and in the segment addition zone, and while these patterns can be relatively conserved among arthropods and the annelid, there have also been changes in the expression of some Wnt genes in the course of protostome evolution. Nevertheless, our results strongly support the parasegment as the primary segmental unit in arthropods, and suggest further similarities between segmental and parasegmental regulation by Wnt genes in annelids and arthropods respectively. Conclusions Despite frequent losses of Wnt gene subfamilies in lineages such as insects, nematodes and leeches, most protostomes have probably maintained much of their ancestral repertoire of twelve Wnt genes. The maintenance of a large set of these ligands could be in part due to their combinatorial activity in various tissues rather than functional redundancy. The activity of such Wnt 'landscapes' as opposed to the function of individual ligands could explain the patterns of conservation and redeployment of these genes in important developmental processes across metazoans. This requires further analysis of the expression and function of these genes in a wider range of taxa.
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- 2010
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11. Unraveling the Genetic Basis for the Rapid Diversification of Male Genitalia between Drosophila Species.
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Hagen, Joanna F D, Mendes, Cláudia C, Booth, Shamma R, Jimenez, Javier Figueras, Tanaka, Kentaro M, Franke, Franziska A, Baudouin-Gonzalez, Luis, Ridgway, Amber M, Arif, Saad, Nunes, Maria D S, and McGregor, Alistair P
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MALE reproductive organs ,DROSOPHILA ,GENE regulatory networks ,SEXUAL selection ,GENE expression - Abstract
In the last 240,000 years, males of the Drosophila simulans species clade have evolved striking differences in the morphology of their epandrial posterior lobes and claspers (surstyli). These appendages are used for grasping the female during mating and so their divergence is most likely driven by sexual selection. Mapping studies indicate a highly polygenic and generally additive genetic basis for these morphological differences. However, we have limited understanding of the gene regulatory networks that control the development of genital structures and how they evolved to result in this rapid phenotypic diversification. Here, we used new D. simulans / D. mauritiana introgression lines on chromosome arm 3L to generate higher resolution maps of posterior lobe and clasper differences between these species. We then carried out RNA-seq on the developing genitalia of both species to identify the expressed genes and those that are differentially expressed between the two species. This allowed us to test the function of expressed positional candidates during genital development in D. melanogaster. We identified several new genes involved in the development and possibly the evolution of these genital structures, including the transcription factors Hairy and Grunge. Furthermore, we discovered that during clasper development Hairy negatively regulates tartan (trn), a gene known to contribute to divergence in clasper morphology. Taken together, our results provide new insights into the regulation of genital development and how this has evolved between species. [ABSTRACT FROM AUTHOR]
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- 2021
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12. Sexual dimorphism and natural variation within and among species in the Drosophila retinal mosaic.
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Hilbrant, Maarten, Almudi, Isabel, Leite, Daniel J, Kuncheria, Linta, Posnien, Nico, Nunes, Maria DS, and McGregor, Alistair P
- Abstract
Background: Insect compound eyes are composed of ommatidia, which contain photoreceptor cells that are sensitive to different wavelengths of light defined by the specific rhodopsin proteins that they express. The fruit fly Drosophila melanogaster has several different ommatidium types that can be localised to specific retinal regions, such as the dorsal rim area (DRA), or distributed stochastically in a mosaic across the retina, like the ‘pale’ and ‘yellow’ types. Variation in these ommatidia patterns very likely has important implications for the vision of insects and could underlie behavioural and environmental adaptations. However, despite the detailed understanding of ommatidia specification in D. melanogaster, the extent to which the frequency and distribution of the different ommatidium types vary between sexes, strains and species of Drosophila is not known. Results: We investigated the frequency and distribution of ommatidium types based on rhodopsin protein expression, and the expression levels of rhodopsin transcripts in the eyes of both sexes of different strains of D. melanogaster, D. simulans and D. mauritiana. We found that while the number of DRA ommatidia was invariant, Rh3 expressing ommatidia were more frequent in the larger eyes of females compared to the males of all species analysed. The frequency and distribution of ommatidium types also differed between strains and species. The D. simulans strain ZOM4 has the highest frequency of Rh3 expressing ommatidia, which is associated with a non-stochastic patch of pale and odd-coupled ommatidia in the dorsal-posterior of their eyes. Conclusions: Our results show that there is striking variation in the frequency and distribution of ommatidium types between sexes, strains and species of Drosophila. This suggests that evolutionary changes in the underlying regulatory mechanisms can alter the distribution of ommatidium types to promote or restrict their expression in specific regions of the eye within and between species, and that this could cause differences in vision among these flies. [ABSTRACT FROM AUTHOR]
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- 2014
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13. Analysis of the Wnt gene repertoire in an onychophoran provides new insights into the evolution of segmentation.
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Hogvall, Mattias, Schönauer, Anna, Budd, Graham E., McGregor, Alistair P., Posnien, Nico, and Janssen, Ralf
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ONYCHOPHORA ,ARTHROPODA ,FRUIT flies ,DROSOPHILA melanogaster ,GENE expression - Abstract
Background The Onychophora are a probable sister group to Arthropoda, one of the most intensively studied animal phyla from a developmental perspective. Pioneering work on the fruit fly Drosophila melanogaster and subsequent investigation of other arthropods has revealed important roles for Wnt genes during many developmental processes in these animals. Results We screened the embryonic transcriptome of the onychophoran Euperipatoides kanangrensis and found that at least 11 Wnt genes are expressed during embryogenesis. These genes represent 11 of the 13 known subfamilies of Wnt genes. Conclusions Many onychophoran Wnt genes are expressed in segment polarity gene-like patterns, suggesting a general role for these ligands during segment regionalization, as has been described in arthropods. During early stages of development, Wnt2, Wnt4, and Wnt5 are expressed in broad multiple segment-wide domains that are reminiscent of arthropod gap and Hox gene expression patterns, which suggests an early instructive role for Wnt genes during E. kanangrensis segmentation. [ABSTRACT FROM AUTHOR]
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- 2014
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14. Evolutionary crossroads in developmental biology: the spider Parasteatoda tepidariorum.
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Hilbrant, Maarten, Damen, Wim G. M., and McGregor, Alistair P.
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DEVELOPMENTAL biology ,BIOLOGICAL evolution ,SPIDERS ,MYRIAPODA ,SEGMENTATION (Biology) ,GENETIC regulation - Abstract
Spiders belong to the chelicerates, which is an arthropod group that branches basally from myriapods, crustaceans and insects. Spiders are thus useful models with which to investigate whether aspects of development are ancestral or derived with respect to the arthropod common ancestor. Moreover, they serve as an important reference point for comparison with the development of other metazoans. Therefore, studies of spider development have made a major contribution to advancing our understanding of the evolution of development. Much of this knowledge has come from studies of the common house spider, Parasteatoda tepidariorum. Here, we describe how the growing number of experimental tools and resources available to study Parasteatoda development have provided novel insights into the evolution of developmental regulation and have furthered our understanding of metazoan body plan evolution. INSETS: Box 1. Glossary;Box 2. Available experimental techniques;Box 3. The evolution of the cumulus. [ABSTRACT FROM AUTHOR]
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- 2012
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15. Shape and function of the Bicoid morphogen gradient in dipteran species with different sized embryos
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Gregor, Thomas, McGregor, Alistair P., and Wieschaus, Eric F.
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INSECTS , *MORPHOGENESIS , *EMBRYOS , *DROSOPHILA - Abstract
Abstract: The Bicoid morphogen evolved approximately 150 MYA from a Hox3 duplication and is only found in higher dipterans. A major difference between dipteran species, however, is the size of the embryo, which varies up to 5-fold. Although the expression of developmental factors scale with egg length, it remains unknown how this scaling is achieved. To test whether scaling is accounted for by the properties of Bicoid, we expressed eGFP fused to the coding region of bicoid from three dipteran species in transgenic Drosophila embryos using the Drosophila bicoid cis-regulatory and mRNA localization sequences. In such embryos, we find that Lucilia sericata and Calliphora vicina Bicoid produce gradients very similar to the endogenous Drosophila gradient and much shorter than what they would have produced in their own respective species. The common shape of the Drosophila, Lucilia and Calliphora Bicoid gradients appears to be a conserved feature of the Bicoid protein. Surprisingly, despite their similar distributions, we find that Bicoid from Lucilia and Calliphora do not rescue Drosophila bicoid mutants, suggesting that that Bicoid proteins have evolved species-specific functional amino acid differences. We also found that maternal expression and anteriorly localization of proteins other than Bcd does not necessarily give rise to a gradient; eGFP produced a uniform protein distribution. However, a shallow gradient was observed using eGFP-NLS, suggesting nuclear localization may be necessary but not sufficient for gradient formation. [Copyright &y& Elsevier]
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- 2008
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16. Modulation and Evolution of Animal Development through microRNA Regulation of Gene Expression.
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Kittelmann, Sebastian and McGregor, Alistair P.
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GENETIC regulation , *ANIMAL development , *BIOLOGICAL evolution , *GENE regulatory networks , *MICRORNA , *GENE expression - Abstract
microRNAs regulate gene expression by blocking the translation of mRNAs and/or promoting their degradation. They, therefore, play important roles in gene regulatory networks (GRNs) by modulating the expression levels of specific genes and can tune GRN outputs more broadly as part of feedback loops. These roles for microRNAs provide developmental buffering on one hand but can facilitate evolution of development on the other. Here we review how microRNAs can modulate GRNs during animal development as part of feedback loops and through their individual or combinatorial targeting of multiple different genes in the same network. We then explore how changes in the expression of microRNAs and consequently targets can facilitate changes in GRNs that alter development and lead to phenotypic evolution. The reviewed studies exemplify the key roles played by microRNAs in the regulation and evolution of gene expression during developmental processes in animals. [ABSTRACT FROM AUTHOR]
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- 2019
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17. The function and evolution of Wnt genes in arthropods
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Murat, Sophie, Hopfen, Corinna, and McGregor, Alistair P.
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ARTHROPODA , *CELLULAR signal transduction , *CELL migration , *LIGANDS (Biochemistry) , *DROSOPHILA genetics , *BIOLOGICAL evolution , *ACYRTHOSIPHON , *COMPARATIVE studies - Abstract
Abstract: Wnt signalling is required for a wide range of developmental processes, from cleavage to patterning and cell migration. There are 13 subfamilies of Wnt ligand genes and this diverse repertoire appeared very early in metazoan evolution. In this review, we first summarise the known Wnt gene repertoire in various arthropods. Insects appear to have lost several Wnt subfamilies, either generally, such as Wnt3, or in lineage specific patterns, for example, the loss of Wnt7 in Anopheles. In Drosophila and Acyrthosiphon, only seven and six Wnt subfamilies are represented, respectively; however, the finding of nine Wnt genes in Tribolium suggests that arthropods had a larger repertoire ancestrally. We then discuss what is currently known about the expression and developmental function of Wnt ligands in Drosophila and other insects in comparison to other arthropods, such as the spiders Achaearanea and Cupiennius. We conclude that studies of Wnt genes have given us much insight into the developmental roles of some of these ligands. However, given the frequent loss of Wnt genes in insects and the derived development of Drosophila, further studies of these important genes are required in a broader range of arthropods to fully understand their developmental function and evolution. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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18. Sox21b underlies the rapid diversification of a novel male genital structure between Drosophila species.
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Ridgway, Amber M., Hood, Emily J., Jimenez, Javier Figueras, Nunes, Maria D.S., and McGregor, Alistair P.
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BIOLOGICAL evolution , *DROSOPHILA , *MALE reproductive organs , *GENE expression , *GENITALIA , *HOMEOBOX genes - Abstract
The emergence and diversification of morphological novelties is a major feature of animal evolution. 1,2,3,4,5,6,7,8,9 However, relatively little is known about the genetic basis of the evolution of novel structures and the mechanisms underlying their diversification. The epandrial posterior lobes of male genitalia are a novelty of particular Drosophila species. 10,11,12,13 The lobes grasp the female ovipositor and insert between her abdominal tergites and, therefore, are important for copulation and species recognition. 10,11,12,14,15,16,17 The posterior lobes likely evolved from co-option of a Hox-regulated gene network from the posterior spiracles 10 and have since diversified in morphology in the D. simulans clade, in particular, over the last 240,000 years, driven by sexual selection. 18,19,20,21 The genetic basis of this diversification is polygenic but, to the best of our knowledge, none of the causative genes have been identified. 22,23,24,25,26,27,28,29,30 Identifying the genes underlying the diversification of these secondary sexual structures is essential to understanding the evolutionary impact on copulation and species recognition. Here, we show that Sox21b negatively regulates posterior lobe size. This is consistent with expanded Sox21b expression in D. mauritiana , which develops smaller posterior lobes than D. simulans. We tested this by generating reciprocal hemizygotes and confirmed that changes in Sox21b underlie posterior lobe evolution between these species. Furthermore, we found that posterior lobe size differences caused by the species-specific allele of Sox21b significantly affect copulation duration. Taken together, our study reveals the genetic basis for the sexual-selection-driven diversification of a novel morphological structure and its functional impact on copulatory behavior. [Display omitted] • Sox21b regulates development of posterior lobes, novel Drosophila genital organs • Higher Sox21b expression in developing genitalia produces smaller posterior lobes • Sox21b underlies posterior lobe divergence between D. simulans and D. mauritiana • The species allele of Sox21b causes differences in the duration of copulation Ridgway et al. show that the transcription factor Sox21b represses the size of the posterior lobes of male Drosophila genitalia. Sox21b expression differs during posterior lobe development between D. mauritiana and D. simulans , and this gene contributes to the evolution of the size of this morphological novelty between these two species. [ABSTRACT FROM AUTHOR]
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- 2024
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19. Characterization of the genetic architecture underlying eye size variation within Drosophila melanogaster and Drosophila simulans.
- Author
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Gaspar, Pedro, Arif, Saad, Sumner-Rooney, Lauren, Kittelmann, Maike, Bodey, Andrew J., Stern, David L., Nunes, Maria D. S., and McGregor, Alistair P.
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DROSOPHILA melanogaster , *DROSOPHILIDAE , *GENE regulatory networks , *EYE , *EYE tracking - Abstract
The compound eyes of insects exhibit striking variation in size, reflecting adaptation to different lifestyles and habitats. However, the genetic and developmental bases of variation in insect eye size is poorly understood, which limits our understanding of how these important morphological differences evolve. To address this, we further explored natural variation in eye size within and between four species of the Drosophila melanogaster species subgroup. We found extensive variation in eye size among these species, and flies with larger eyes generally had a shorter inter-ocular distance and vice versa. We then carried out quantitative trait loci (QTL) mapping of intra-specific variation in eye size and inter-ocular distance in both D. melanogaster and D. simulans. This revealed that different genomic regions underlie variation in eye size and inter-ocular distance in both species, which we corroborated by introgression mapping in D. simulans. This suggests that although there is a trade-off between eye size and inter-ocular distance, variation in these two traits is likely to be caused by different genes and so can be genetically decoupled. Finally, although we detected QTL for intra-specific variation in eye size at similar positions in D. melanogaster and D. simulans, we observed differences in eye fate commitment between strains of these two species. This indicates that different developmental mechanisms and therefore, most likely, different genes contribute to eye size variation in these species. Taken together with the results of previous studies, our findings suggest that the gene regulatory network that specifies eye size has evolved at multiple genetic nodes to give rise to natural variation in this trait within and among species. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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20. The Evolution of Sox Gene Repertoires and Regulation of Segmentation in Arachnids
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Steven Russell, Prashant P. Sharma, Grace Blakeley, Alistair P. McGregor, Lauren Sumner-Rooney, Anna Schoenauer, Saad Arif, Michael Seiter, Luis Baudouin-Gonzalez, Amber Harper, Arif, Saad [0000-0003-0811-8604], Sumner-Rooney, Lauren [0000-0003-0196-5069], Russell, Steven [0000-0003-0546-3031], Sharma, Prashant P [0000-0002-2328-9084], McGregor, Alistair P [0000-0002-2908-2420], and Apollo - University of Cambridge Repository
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Male ,Gene regulatory network ,arthropods ,AcademicSubjects/SCI01180 ,Phalangium opilio ,Evolution, Molecular ,03 medical and health sciences ,spiders ,0302 clinical medicine ,Gene duplication ,Sox genes ,arachnids ,evolution ,Arachnida ,Melanogaster ,Genetics ,Gene family ,Animals ,Molecular Biology ,Gene ,Transcription factor ,development ,Ecology, Evolution, Behavior and Systematics ,Discoveries ,SOX Transcription Factors ,Tagma ,030304 developmental biology ,0303 health sciences ,Parasteatoda tepidariorum ,biology ,segmentation ,AcademicSubjects/SCI01130 ,biology.organism_classification ,Evolutionary biology ,Subfunctionalization ,Neofunctionalization ,Female ,Drosophila melanogaster ,030217 neurology & neurosurgery - Abstract
The Sox family of transcription factors regulate many different processes during metazoan development, including stem cell maintenance, nervous system specification and germline development. In addition, it has recently become apparent that SoxB genes are involved in embryonic segmentation in several arthropod species. Segmentation in arthropods occurs in two main ways: long germ animals form all segments at once, best exemplified in the well-studied Drosophila melanogaster system, and short germ animals form anterior segments simultaneously, with posterior segments added sequentially from a segment addition zone. In both D. melanogaster and the short germ beetle Tribolium castaneum, the SoxB gene Dichaete is required for correct segmentation and, more recently, we showed that a close relative of Dichaete, Sox21b-1, is required for the simultaneous formation of prosomal segments and sequential addition of opisthosomal segments in the spider Parasteatoda tepidariorum. Here we further analysed the function and expression of Sox21b-1 in P. tepidariorum. We found that while this gene regulates the generation of both prosomal and opisthosomal segments, it plays different roles in the formation of these tagma reflecting their contrasting modes of segmentation and deployment of gene regulatory networks with different architectures. To further investigate the evolution of Sox genes and their roles we characterised the repertoire of the gene family across several arachnid species with and without an ancestral whole genome duplication, and compared Sox expression between P. tepidariorum and the harvestman Phalangium opilio. The results suggest that Sox21b-1 was likely involved in segmentation ancestrally in arachnids, but that other Sox genes could also regulate this process in these animals. We also found that most Sox families have been retained as duplicates or ohnologs after WGD and evidence for potential subfunctionalisation and/or neofunctionalization events.
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- 2021
21. A SoxB gene acts as an anterior gap gene and regulates posterior segment addition in a spider
- Author
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Christian Louis Bonatto Paese, Anna Schoenauer, Daniel J Leite, Steven Russell, Alistair P McGregor, Paese, Christian Louis Bonatto [0000-0001-5992-5209], Russell, Steven [0000-0003-0546-3031], McGregor, Alistair P [0000-0002-2908-2420], and Apollo - University of Cambridge Repository
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QH301-705.5 ,Science ,evolutionary biology ,segmentation ,Gene Expression Regulation, Developmental ,Spiders ,Biological Evolution ,developmental biology ,evolution ,SOXB2 Transcription Factors ,Medicine ,Animals ,Other ,parasteatoda tepidariorum ,Biology (General) ,development ,spider ,Research Article ,Body Patterning - Abstract
Sox genes encode a set of highly conserved transcription factors that regulate many developmental processes. In insects, the SoxB gene Dichaete is the only Sox gene known to be involved in segmentation. To determine if similar mechanisms are used in other arthropods, we investigated the role of Sox genes during segmentation in the spider Parasteatoda tepidariorum. While Dichaete does not appear to be involved in spider segmentation, we found that the closely related Sox21b-1 gene acts as a gap gene during formation of anterior segments and is also part of the segmentation clock for development of the segment addition zone and sequential addition of opisthosomal segments. Thus, we have found that two different mechanisms of segmentation in a non-mandibulate arthropod are regulated by a SoxB gene. Our work provides new insights into the function of an important and conserved gene family, and the evolution of the regulation of segmentation in arthropods., eLife digest Insects, spiders, centipedes and lobsters all belong to a group of animals known as arthropods. A common feature of these animals is that their bodies are made up of repeated segments. However different arthropods build their segmented bodies in different ways. For example, the fruit fly makes all of its segments at the same time, while most other arthropods – including spiders – make a few segments at once and then add the rest, one or two at a time, to the rear end of their bodies. Recent research in different insects has shown that these two processes – adding segments simultaneously or sequentially – are more similar than previously thought. This research also showed that these processes involve a gene called Dichaete, which belongs to the Sox gene family. However it was not known if Sox genes also control the production of segments in other arthropods like spiders. Paese et al. have now found that, just like insects, the common house spider does indeed require a Sox gene to form its segments. Specifically, the experiments revealed that spiders need a Sox gene called Sox21b-1 to make both the segments that carry their legs (which are made all at once), and the segments that make up the rear of their bodies (which are added one at a time). Since spiders and insects both use a Sox gene to control the formation of their body segments, it is likely that the ancestor of arthropods used one too. However, because spiders and insects use a different Sox gene for these processes, Paese et al. suggest that one gene may have replaced the role of the other during the evolution of insects and spiders. Together these findings broaden the current understanding of how genes interact to organise cells to build organisms and how these processes evolve over time. Furthermore, since Sox genes direct many important events in all animals, including humans, the discovery of a new role for one of these genes may help scientists to better understand the development of other animals too.
- Published
- 2018
- Full Text
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