scholarly journals Novel insights on obligate symbiont lifestyle and adaptation to chemosynthetic environment as revealed by the giant tubeworm genome

2021 ◽  
Author(s):  
Andre Luiz de Oliveira ◽  
Jessica Mitchell ◽  
Peter Girguis ◽  
Monika Bright
Keyword(s):  
Immune System ◽  
Draft Genome ◽  
Gene Families ◽  
Gene Repertoire ◽  
Riftia Pachyptila ◽  
Intracellular Digestion ◽  
Obligate Symbiont ◽  
Highly Expressed Genes ◽  
Complete Mitogenome ◽  
Genome Information

The mutualism between the giant tubeworm Riftia pachyptila and its endosymbiont Candidatus Endoriftia persephone has been extensively researched over the past 40 years. However, the lack of the host whole genome information has impeded the full comprehension of the genotype/phenotype interface in Riftia. Here we described the high-quality draft genome of Riftia, its complete mitogenome, and tissue-specific transcriptomic data. The Riftia genome presents signs of reductive evolution, with gene family contractions exceeding expansions. Expanded gene families are related to sulphur metabolism, detoxification, anti-oxidative stress, oxygen transport, immune system, and lysosomal digestion, reflecting evolutionary adaptations to the vent environment and endosymbiosis. Despite the derived body plan, the developmental gene repertoire in the gutless tubeworm is extremely conserved with the presence of a near intact and complete Hox cluster. Gene expression analyses establishes that the trophosome is a multi-functional organ marked by intracellular digestion of endosymbionts, storage of excretory products and haematopoietic functions. Overall, the plume and gonad tissues both in contact to the environment harbour highly expressed genes involved with cell cycle, programmed cell death, and immunity indicating a high cell turnover and defence mechanisms against pathogens. We posit that the innate immune system plays a more prominent role into the establishment of the symbiosis during the infection in the larval stage, rather than maintaining the symbiostasis in the trophosome. This genome bridges four decades of physiological research in Riftia, whilst simultaneously provides new insights into the development, whole organism functions and evolution in the giant tubeworm.

scholarly journals The genome of the blind soil-dwelling and ancestrally wingless dipluran Campodea augens, a key reference hexapod for studying the emergence of insect innovations

2019 ◽  
Author(s):  
Mosè Manni ◽  
Felipe A. Simao ◽  
Hugh M. Robertson ◽  
Marco A. Gabaglio ◽  
Robert M. Waterhouse ◽  
...  
Keyword(s):  
Draft Genome ◽  
Gene Families ◽  
Sister Group ◽  
Sensu Stricto ◽  
Comparative Genomic ◽  
Gene Repertoire ◽  
Animal Group ◽  
Origin And Evolution ◽  
Genomic Analyses ◽  
Metabolism Gene

AbstractThe dipluran two-pronged bristletail Campodea augens is a blind ancestrally wingless hexapod with the remarkable capacity to regenerate lost body appendages such as its long antennae. As sister group to Insecta (sensu stricto), Diplura are key to understanding the early evolution of hexapods and the origin and evolution of insects. Here we report the 1.2-Gbp draft genome of C. augens and results from comparative genomic analyses with other arthropods. In C. augens we uncovered the largest chemosensory gene repertoire of ionotropic receptors in the animal kingdom, a massive expansion which might compensate for the loss of vision. We found a paucity of photoreceptor genes mirroring at the genomic level the secondary loss of an ancestral external photoreceptor organ. Expansions of detoxification and carbohydrate metabolism gene families might reflect adaptations for foraging behaviour, and duplicated apoptotic genes might underlie its high regenerative potential.The C. augens genome represents one of the key references for studying the emergence of genomic innovations in insects, the most diverse animal group, and opens up novel opportunities to study the under-explored biology of diplurans.

scholarly journals The Genome of the Blind Soil-Dwelling and Ancestrally Wingless Dipluran Campodea augens: A Key Reference Hexapod for Studying the Emergence of Insect Innovations

2019 ◽  
Vol 12 (1) ◽  
pp. 3534-3549
Author(s):  
Mosè Manni ◽  
Felipe A Simao ◽  
Hugh M Robertson ◽  
Marco A Gabaglio ◽  
Robert M Waterhouse ◽  
...  
Keyword(s):  
Draft Genome ◽  
Gene Families ◽  
Sister Group ◽  
Sensu Stricto ◽  
Comparative Genomic ◽  
Gene Repertoire ◽  
Animal Group ◽  
Origin And Evolution ◽  
Genomic Analyses ◽  
Metabolism Gene

Abstract The dipluran two-pronged bristletail Campodea augens is a blind ancestrally wingless hexapod with the remarkable capacity to regenerate lost body appendages such as its long antennae. As sister group to Insecta (sensu stricto), Diplura are key to understanding the early evolution of hexapods and the origin and evolution of insects. Here we report the 1.2-Gb draft genome of C. augens and results from comparative genomic analyses with other arthropods. In C. augens, we uncovered the largest chemosensory gene repertoire of ionotropic receptors in the animal kingdom, a massive expansion that might compensate for the loss of vision. We found a paucity of photoreceptor genes mirroring at the genomic level the secondary loss of an ancestral external photoreceptor organ. Expansions of detoxification and carbohydrate metabolism gene families might reflect adaptations for foraging behavior, and duplicated apoptotic genes might underlie its high regenerative potential. The C. augens genome represents one of the key references for studying the emergence of genomic innovations in insects, the most diverse animal group, and opens up novel opportunities to study the under-explored biology of diplurans.

scholarly journals Expansion of the antimicrobial peptide repertoire in the invasive ladybird Harmonia axyridis

2013 ◽  
Vol 280 (1750) ◽  
pp. 20122113 ◽  
Author(s):  
Andreas Vilcinskas ◽  
Krishnendu Mukherjee ◽  
Heiko Vogel
Keyword(s):  
Immune System ◽  
Harmonia Axyridis ◽  
Invasion Biology ◽  
Gene Families ◽  
Immune Gene ◽  
Gene Repertoire ◽  
System A ◽  
Genes Encoding ◽  
Induction Ratio ◽  
Bacteria And Fungi

The harlequin ladybird beetle Harmonia axyridis has emerged as a model species in invasion biology because of its strong resistance against pathogens and remarkable capacity to outcompete native ladybirds. The invasive success of the species may reflect its well-adapted immune system, a hypothesis we tested by analysing the transcriptome and characterizing the immune gene repertoire of untreated beetles and those challenged with bacteria and fungi. We found that most H. axyridis immunity-related genes were similar in diversity to their counterparts in the reference beetle Tribolium castaneum , but there was an unprecedented expansion among genes encoding antimicrobial peptides and proteins (AMPs). We identified more than 50 putative AMPs belonging to seven different gene families, and many of the corresponding genes were shown by quantitative real-time RT–PCR to be induced in the immune-stimulated beetles. AMPs with the highest induction ratio in the challenged beetles were shown to demonstrate broad and potent activity against Gram-negative bacteria and entomopathogenic fungi. The invasive success of H. axyridis can therefore be attributed at least in part to the greater efficiency of its immune system, particularly the expansion of AMP gene families and their induction in response to pathogens.

scholarly journals The draft genome of the specialist flea beetle Altica viridicyanea (Coleoptera: Chrysomelidae)

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Huai-Jun Xue ◽  
Yi-Wei Niu ◽  
Kari A. Segraves ◽  
Rui-E Nie ◽  
Ya-Jing Hao ◽  
...  
Keyword(s):  
Host Plant ◽  
Plant Cell Wall ◽  
Flea Beetle ◽  
Repetitive Sequences ◽  
Draft Genome ◽  
Gene Families ◽  
Ecological Speciation ◽  
Secondary Chemistry ◽  
Host Plant Specialization ◽  
Insight Into

Abstract Background Altica (Coleoptera: Chrysomelidae) is a highly diverse and taxonomically challenging flea beetle genus that has been used to address questions related to host plant specialization, reproductive isolation, and ecological speciation. To further evolutionary studies in this interesting group, here we present a draft genome of a representative specialist, Altica viridicyanea, the first Alticinae genome reported thus far. Results The genome is 864.8 Mb and consists of 4490 scaffolds with a N50 size of 557 kb, which covered 98.6% complete and 0.4% partial insect Benchmarking Universal Single-Copy Orthologs. Repetitive sequences accounted for 62.9% of the assembly, and a total of 17,730 protein-coding gene models and 2462 non-coding RNA models were predicted. To provide insight into host plant specialization of this monophagous species, we examined the key gene families involved in chemosensation, detoxification of plant secondary chemistry, and plant cell wall-degradation. Conclusions The genome assembled in this work provides an important resource for further studies on host plant adaptation and functionally affiliated genes. Moreover, this work also opens the way for comparative genomics studies among closely related Altica species, which may provide insight into the molecular evolutionary processes that occur during ecological speciation.

scholarly journals Gene family innovation, conservation and loss on the animal stem lineage

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Daniel J Richter ◽  
Parinaz Fozouni ◽  
Michael B Eisen ◽  
Nicole King
Keyword(s):  
Gene Family ◽  
Gene Families ◽  
Gene Content ◽  
Gene Repertoire ◽  
Toll Like Receptor ◽  
Stem Lineage ◽  
Gains And Losses ◽  
Core Features

Choanoflagellates, the closest living relatives of animals, can provide unique insights into the changes in gene content that preceded the origin of animals. However, only two choanoflagellate genomes are currently available, providing poor coverage of their diversity. We sequenced transcriptomes of 19 additional choanoflagellate species to produce a comprehensive reconstruction of the gains and losses that shaped the ancestral animal gene repertoire. We identified ~1944 gene families that originated on the animal stem lineage, of which only 39 are conserved across all animals in our study. In addition, ~372 gene families previously thought to be animal-specific, including Notch, Delta, and homologs of the animal Toll-like receptor genes, instead evolved prior to the animal-choanoflagellate divergence. Our findings contribute to an increasingly detailed portrait of the gene families that defined the biology of the Urmetazoan and that may underpin core features of extant animals.

scholarly journals Ecological correlates of gene family size: the draft genome of the redheaded pine sawfly Neodiprion lecontei

2021 ◽  
Author(s):  
Kim Vertacnik ◽  
Danielle Herrig ◽  
R Keating Godfrey ◽  
Tom Hill ◽  
Scott Geib ◽  
...  
Keyword(s):  
Gene Family ◽  
Family Size ◽  
Draft Genome ◽  
Gene Families ◽  
Gene Family Evolution ◽  
Gene Gain ◽  
Ecological Specialization ◽  
Dietary Specialization ◽  
Pine Sawfly ◽  
Neodiprion Lecontei

A central goal in evolutionary biology is to determine the predictability of adaptive genetic changes. Despite many documented cases of convergent evolution at individual loci, little is known about the repeatability of gene family expansions and contractions. To address this void, we examined gene family evolution in the redheaded pine sawfly Neodiprion lecontei, a non-eusocial hymenopteran and exemplar of a pine-specialized lineage evolved from angiosperm-feeding ancestors. After assembling and annotating a draft genome, we manually annotated multiple gene families with chemosensory, detoxification, or immunity functions and characterized their genomic distributions and evolutionary history. Our results suggest that expansions of bitter gustatory receptor (GR), clan 3 cytochrome P450 (CYP3), and antimicrobial peptide (AMP) subfamilies may have contributed to pine adaptation. By contrast, there was no evidence of recent gene family contraction via pseudogenization. Next, we compared the number of genes in these same families across insect taxa that vary in diet, dietary specialization, and social behavior. In Hymenoptera, herbivory was associated with large GR and small olfactory receptor (OR) families, eusociality was associated with large OR and small AMP families, and--unlike investigations among more closely related taxa--ecological specialization was not related to gene family size. Overall, our results suggest that gene families that mediate ecological interactions may expand and contract predictably in response to particular selection pressures, however, the ecological drivers and temporal pace of gene gain and loss likely varies considerably across gene families.

scholarly journals Expansion, retention and loss in the Acyl-CoA Synthetase “Bubblegum” (Acsbg) gene family in vertebrate history

2018 ◽  
Author(s):  
Mónica Lopes-Marques ◽  
André M. Machado ◽  
Raquel Ruivo ◽  
Elza Fonseca ◽  
Estela Carvalho ◽  
...  
Keyword(s):  
Gene Family ◽  
Metabolic Pathways ◽  
Evolutionary History ◽  
Gene Families ◽  
Gene Repertoire ◽  
Physiological Processes ◽  
Complex Lipid ◽  
History Of ◽  
Enzyme Families ◽  
Rate Limiting

AbstractFatty acids (FAs) constitute a considerable fraction of all lipid molecules with a fundamental role in numerous physiological processes. In animals, the majority of complex lipid molecules are derived from the transformation of FAs through several biochemical pathways. Yet, for FAs to enroll in these pathways they require an activation step. FA activation is catalyzed by the rate limiting action of Acyl-CoA synthases. Several Acyl-CoA enzyme families have been previously described and classified according to the chain length of FA they process. Here, we address the evolutionary history of the ACSBG gene family which activates, FA with more than 16 carbons. Currently, two different ACSBG gene families, ACSBG1 and ACSBG2, are recognized in vertebrates. We provide evidence that a wider and unequal ACSBG gene repertoire is present in vertebrate lineages. We identify a novel ACSBG-like gene lineage which occurs specifically in amphibians, ray finned fish, coelacanths and chondrichthyes named ACSBG3. Also, we show that the ACSBG2 gene lineage duplicated in the Theria ancestor. Our findings, thus offer a far richer understanding on FA activation in vertebrates and provide key insights into the relevance of comparative and functional analysis to perceive physiological differences, namely those related with lipid metabolic pathways.

scholarly journals Discovery of a New TLR Gene and Gene Expansion Event through Improved Desert Tortoise Genome Assembly with Chromosome-Scale Scaffolds

2020 ◽  
Vol 12 (2) ◽  
pp. 3917-3925
Author(s):  
Greer A Dolby ◽  
Matheo Morales ◽  
Timothy H Webster ◽  
Dale F DeNardo ◽  
Melissa A Wilson ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Mojave Desert ◽  
De Novo ◽  
Stop Codon ◽  
Draft Genome ◽  
Gene Families ◽  
Sea Turtle ◽  
Desert Tortoise ◽  
Draft Genome Assembly ◽  
Gene Expansion

Abstract Toll-like receptors (TLRs) are a complex family of innate immune genes that are well characterized in mammals and birds but less well understood in nonavian sauropsids (reptiles). The advent of highly contiguous draft genomes of nonmodel organisms enables study of such gene families through analysis of synteny and sequence identity. Here, we analyze TLR genes from the genomes of 22 tetrapod species. Findings reveal a TLR8 gene expansion in crocodilians and turtles (TLR8B), and a second duplication (TLR8C) specifically within turtles, followed by pseudogenization of that gene in the nonfreshwater species (desert tortoise and green sea turtle). Additionally, the Mojave desert tortoise (Gopherus agassizii) has a stop codon in TLR8B (TLR8-1) that is polymorphic among conspecifics. Revised orthology further reveals a new TLR homolog, TLR21-like, which is exclusive to lizards, snakes, turtles, and crocodilians. These analyses were made possible by a new draft genome assembly of the desert tortoise (gopAga2.0), which used chromatin-based assembly to yield draft chromosomal scaffolds (L50 = 26 scaffolds, N50 = 28.36 Mb, longest scaffold = 107 Mb) and an enhanced de novo genome annotation with 25,469 genes. Our three-step approach to orthology curation and comparative analysis of TLR genes shows what new insights are possible using genome assemblies with chromosome-scale scaffolds that permit integration of synteny conservation data.

scholarly journals Draft Genome Sequence of Putative 2-Methylisoborneol-Producing Pseudanabaena yagii Strain GIHE-NHR1, Isolated from the North Han River in South Korea

2020 ◽  
Vol 9 (27) ◽  
Author(s):  
Ju-Yong Jeong ◽  
Sang-Hoon Lee ◽  
Mi-Ra Yun ◽  
Seung-Eun Oh ◽  
Tae-Hwa Kim ◽  
...  
Keyword(s):  
South Korea ◽  
Genome Sequence ◽  
Genome Analysis ◽  
Draft Genome ◽  
Draft Genome Sequence ◽  
Filamentous Cyanobacterium ◽  
Comparative Genome Analysis ◽  
Han River ◽  
The North ◽  
Genome Information

ABSTRACT The draft genome sequence of Pseudanabaena yagii GIHE-NHR1, a filamentous cyanobacterium, is reported here. Comparative genome analysis suggests that this strain can produce an odor-causing compound (2-methylisoborneol) in water. The genome information is expected to improve the understanding of the putative 2-methylisoborneol production by the bacterium.

scholarly journals Genome ofCrucihimalaya himalaica, a close relative ofArabidopsis, shows ecological adaptation to high altitude

2019 ◽  
Vol 116 (14) ◽  
pp. 7137-7146 ◽  
Author(s):  
Ticao Zhang ◽  
Qin Qiao ◽  
Polina Yu. Novikova ◽  
Qia Wang ◽  
Jipei Yue ◽  
...  
Keyword(s):  
Dna Repair ◽  
Positive Selection ◽  
Genome Sequence ◽  
Draft Genome ◽  
Extreme Environments ◽  
Gene Families ◽  
Ecological Adaptation ◽  
Tibet Plateau ◽  
Close Relative ◽  
Arabidopsis Lyrata

Crucihimalaya himalaica, a close relative ofArabidopsisandCapsella, grows on the Qinghai–Tibet Plateau (QTP) about 4,000 m above sea level and represents an attractive model system for studying speciation and ecological adaptation in extreme environments. We assembled a draft genome sequence of 234.72 Mb encoding 27,019 genes and investigated its origin and adaptive evolutionary mechanisms. Phylogenomic analyses based on 4,586 single-copy genes revealed thatC. himalaicais most closely related toCapsella(estimated divergence 8.8 to 12.2 Mya), whereas both species form a sister clade toArabidopsis thalianaandArabidopsis lyrata, from which they diverged between 12.7 and 17.2 Mya. LTR retrotransposons inC. himalaicaproliferated shortly after the dramatic uplift and climatic change of the Himalayas from the Late Pliocene to Pleistocene. Compared with closely related species,C. himalaicashowed significant contraction and pseudogenization in gene families associated with disease resistance and also significant expansion in gene families associated with ubiquitin-mediated proteolysis and DNA repair. We identified hundreds of genes involved in DNA repair, ubiquitin-mediated proteolysis, and reproductive processes with signs of positive selection. Gene families showing dramatic changes in size and genes showing signs of positive selection are likely candidates forC. himalaica’s adaptation to intense radiation, low temperature, and pathogen-depauperate environments in the QTP. Loss of function at the S-locus, the reason for the transition to self-fertilization ofC. himalaica, might have enabled its QTP occupation. Overall, the genome sequence ofC. himalaicaprovides insights into the mechanisms of plant adaptation to extreme environments.

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