Giant African snail genomes provide insights into molluscan whole-genome duplication and aquatic-terrestrial transition

AbstractWhole-genome duplication (WGD) has been observed across a wide variety of eukaryotic groups, contributing to evolutionary diversity and environmental adaptability. Mollusks are the second largest group of animals, and are among the organisms that have successfully adapted to the nonmarine realm through aquatic-terrestrial (A-T) transition, and no comprehensive research on WGD has been reported in this group. To explore WGD and the A-T transition in Mollusca, we assembled a chromosome-level reference genome for the giant African snail Achatina immaculata, a global invasive species, and compared the genomes of two giant African snails (A. immaculata and Achatina fulica) to the other available mollusk genomes. The chromosome-level macrosynteny, colinearity blocks, Ks peak and Hox gene clusters collectively suggested the occurrence of a WGD event shared by A. immaculata and A. fulica. The estimated timing of this WGD event (∼70 MYA) was close to the speciation age of the Sigmurethra-Orthurethra (within Stylommatophora) lineage and the Cretaceous-Tertiary (K-T) mass extinction, indicating that the WGD reported herein may have been a common event shared by all Sigmurethra-Orthurethra species and could have conferred ecological adaptability and genomic plasticity allowing the survival of the K-T extinction. Based on macrosynteny, we deduced an ancestral karyotype containing 8 conserved clusters for the Gastropoda-Bivalvia lineage. To reveal the mechanism of WGD in shaping adaptability to terrestrial ecosystems, we investigated gene families related to the respiration, aestivation and immune defense of giant African snails. Several mucus-related gene families expanded early in the Stylommatophora lineage, functioning in water retention, immune defense and wound healing. The hemocyanins, PCK and FBP families were doubled and retained after WGD, enhancing the capacity for gas exchange and glucose homeostasis in aestivation. After the WGD, zinc metalloproteinase genes were highly tandemly duplicated to protect tissue against ROS damage. This evidence collectively suggests that although the WGD may not have been the direct driver of the A-T transition, it provided an important legacy for the terrestrial adaptation of the giant African snail.

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A chromosome‐level genome assembly of Brachymystax lenok tsinlingensis provides new insights into salmonids evolution

10.22541/au.162145887.76699677/v1 ◽

2021 ◽

Author(s):

Wenbo Zhu ◽

Zhongkai Wang ◽

Haorong Li ◽

Hui Xiang ◽

Ping Li ◽

...

Keyword(s):

Genome Assembly ◽

Whole Genome Duplication ◽

Genome Duplication ◽

Gc Content ◽

Gene Families ◽

Whole Genome ◽

Genome Duplication Event ◽

Brachymystax Lenok Tsinlingensis ◽

Brachymystax Lenok ◽

Chromosome Level

The salmonid-specific fourth vertebrate whole-genome duplication (Ss4R) occurred ~80 million years ago in the ancestor of all salmonids and provides a unique opportunity to study the evolutionary history of the duplicated genome. Study of the genome of Brachymystax lenok tsinlingensis might be particularly insightful given that this is the only Brachymystax species with a published salmonid genome. Here, we present a high-quality chromosome-level genome assembly for B. l. tsinlingensis and found that the salmonids have a unique GC content and codon usage, have undergone a whole-genome duplication event and a burst of transposon-mediated repeat expansion, have a slower evolutionary rate, and possess specific expanded gene families and unique positively selected genes. Generally, the B. l. tsinlingensis genome could provide a valuable reference for the study of other salmonids as well as aid the conservation of this endangered species.

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Phylogenetic Analysis of T-Box Genes Demonstrates the Importance of Amphioxus for Understanding Evolution of the Vertebrate Genome

Genetics ◽

10.1093/genetics/156.3.1249 ◽

2000 ◽

Vol 156 (3) ◽

pp. 1249-1257

Author(s):

Ilya Ruvinsky ◽

Lee M Silver ◽

Jeremy J Gibson-Brown

Keyword(s):

Phylogenetic Analysis ◽

Whole Genome Duplication ◽

Genome Duplication ◽

Gene Families ◽

Vertebrate Evolution ◽

Whole Genome ◽

Vertebrate Genome ◽

T Box ◽

Genetic Complexity ◽

History Of

Abstract The duplication of preexisting genes has played a major role in evolution. To understand the evolution of genetic complexity it is important to reconstruct the phylogenetic history of the genome. A widely held view suggests that the vertebrate genome evolved via two successive rounds of whole-genome duplication. To test this model we have isolated seven new T-box genes from the primitive chordate amphioxus. We find that each amphioxus gene generally corresponds to two or three vertebrate counterparts. A phylogenetic analysis of these genes supports the idea that a single whole-genome duplication took place early in vertebrate evolution, but cannot exclude the possibility that a second duplication later took place. The origin of additional paralogs evident in this and other gene families could be the result of subsequent, smaller-scale chromosomal duplications. Our findings highlight the importance of amphioxus as a key organism for understanding evolution of the vertebrate genome.

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Chromosome-level genome assembly of Ophiorrhiza pumila reveals the evolution of camptothecin biosynthesis

Nature Communications ◽

10.1038/s41467-020-20508-2 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Amit Rai ◽

Hideki Hirakawa ◽

Ryo Nakabayashi ◽

Shinji Kikuchi ◽

Koki Hayashi ◽

...

Keyword(s):

Genome Assembly ◽

Whole Genome Duplication ◽

Experimental Validation ◽

Genome Duplication ◽

Indole Alkaloids ◽

Whole Genome ◽

Comparative Genome Analysis ◽

Plant Genomes ◽

Genome Triplication ◽

Chromosome Level

AbstractPlant genomes remain highly fragmented and are often characterized by hundreds to thousands of assembly gaps. Here, we report chromosome-level reference and phased genome assembly of Ophiorrhiza pumila, a camptothecin-producing medicinal plant, through an ordered multi-scaffolding and experimental validation approach. With 21 assembly gaps and a contig N50 of 18.49 Mb, Ophiorrhiza genome is one of the most complete plant genomes assembled to date. We also report 273 nitrogen-containing metabolites, including diverse monoterpene indole alkaloids (MIAs). A comparative genomics approach identifies strictosidine biogenesis as the origin of MIA evolution. The emergence of strictosidine biosynthesis-catalyzing enzymes precede downstream enzymes’ evolution post γ whole-genome triplication, which occurred approximately 110 Mya in O. pumila, and before the whole-genome duplication in Camptotheca acuminata identified here. Combining comparative genome analysis, multi-omics analysis, and metabolic gene-cluster analysis, we propose a working model for MIA evolution, and a pangenome for MIA biosynthesis, which will help in establishing a sustainable supply of camptothecin.

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A chromosome-level genome of the spider Trichonephila antipodiana reveals the genetic basis of its polyphagy and evidence of an ancient whole-genome duplication event

GigaScience ◽

10.1093/gigascience/giab016 ◽

2021 ◽

Vol 10 (3) ◽

Author(s):

Zheng Fan ◽

Tao Yuan ◽

Piao Liu ◽

Lu-Yu Wang ◽

Jian-Feng Jin ◽

...

Keyword(s):

Whole Genome Duplication ◽

Large Scale ◽

Hox Genes ◽

Genome Duplication ◽

Duplication Event ◽

Whole Genome ◽

High Quality ◽

Genome Duplication Event ◽

Whole Genome Duplication Event ◽

Chromosome Level

Abstract Background The spider Trichonephila antipodiana (Araneidae), commonly known as the batik golden web spider, preys on arthropods with body sizes ranging from ∼2 mm in length to insects larger than itself (>20‒50 mm), indicating its polyphagy and strong dietary detoxification abilities. Although it has been reported that an ancient whole-genome duplication event occurred in spiders, lack of a high-quality genome has limited characterization of this event. Results We present a chromosome-level T. antipodiana genome constructed on the basis of PacBio and Hi-C sequencing. The assembled genome is 2.29 Gb in size with a scaffold N50 of 172.89 Mb. Hi-C scaffolding assigned 98.5% of the bases to 13 pseudo-chromosomes, and BUSCO completeness analysis revealed that the assembly included 94.8% of the complete arthropod universal single-copy orthologs (n = 1,066). Repetitive elements account for 59.21% of the genome. We predicted 19,001 protein-coding genes, of which 96.78% were supported by transcriptome-based evidence and 96.32% matched protein records in the UniProt database. The genome also shows substantial expansions in several detoxification-associated gene families, including cytochrome P450 mono-oxygenases, carboxyl/cholinesterases, glutathione-S-transferases, and ATP-binding cassette transporters, reflecting the possible genomic basis of polyphagy. Further analysis of the T. antipodiana genome architecture reveals an ancient whole-genome duplication event, based on 2 lines of evidence: (i) large-scale duplications from inter-chromosome synteny analysis and (ii) duplicated clusters of Hox genes. Conclusions The high-quality T. antipodiana genome represents a valuable resource for spider research and provides insights into this species’ adaptation to the environment.

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Comparative Genomics of Six Juglans Species Reveals Patterns of Disease-associated Gene Family Contractions

10.1101/561738 ◽

2019 ◽

Author(s):

Alex Trouern-Trend ◽

Taylor Falk ◽

Sumaira Zaman ◽

Madison Caballero ◽

David B. Neale ◽

...

Keyword(s):

Gene Family ◽

Whole Genome Duplication ◽

Common Ancestor ◽

Genome Duplication ◽

Gene Prediction ◽

Gene Families ◽

Whole Genome ◽

High Quality ◽

Gene Models ◽

Genome Annotations

ABSTRACTJuglans (walnuts), the most speciose genus in the walnut family (Juglandaceae) represents most of the family’s commercially valuable fruit and wood-producing trees and includes several species used as rootstock in agriculture for their resistance to various abiotic and biotic stressors. We present the full structural and functional genome annotations of six Juglans species and one outgroup within Juglandaceae (Juglans regia, J. cathayensis, J. hindsii, J. microcarpa, J. nigra, J. sigillata and Pterocarya stenoptera) produced using BRAKER2 semi-unsupervised gene prediction pipeline and additional in-house developed tools. For each annotation, gene predictors were trained using 19 tissue-specific J. regia transcriptomes aligned to the genomes. Additional functional evidence and filters were applied to multiexonic and monoexonic putative genes to yield between 27,000 and 44,000 high-confidence gene models per species. Comparison of gene models to the BUSCO embryophyta dataset suggested that, on average, genome annotation completeness was 89.6%. We utilized these high quality annotations to assess gene family evolution within Juglans and among Juglans and selected Eurosid species, which revealed significant contractions in several gene families in J. hindsii including disease resistance-related Wall-associated Kinase (WAK) and Catharanthus roseus Receptor-like Kinase (CrRLK1L) and others involved in abiotic stress response. Finally, we confirmed an ancient whole genome duplication that took place in a common ancestor of Juglandaceae using site substitution comparative analysis.SIGNIFICANCEHigh-quality full genome annotations for six species of walnut (Juglans) and a wingnut (Pterocarya) outgroup were constructed using semi-unsupervised gene prediction followed by gene model filtering and functional characterization. These annotations represent the most comprehensive set for any hardwood genus to date. Comparative analyses based on the gene models uncovered rapid evolution in multiple gene families related to disease-response and a whole genome duplication in a Juglandaceae common ancestor.

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Horseshoe crab genomes reveal the evolution of genes and microRNAs after three rounds of whole genome duplication

Communications Biology ◽

10.1038/s42003-020-01637-2 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Wenyan Nong ◽

Zhe Qu ◽

Yiqian Li ◽

Tom Barton-Owen ◽

Annette Y. P. Wong ◽

...

Keyword(s):

Whole Genome Duplication ◽

Horseshoe Crab ◽

Genome Duplication ◽

Population Level ◽

Gene Families ◽

Whole Genome ◽

Horseshoe Crabs ◽

The Individual ◽

Evolutionary Consequences ◽

High Quality Genome

AbstractWhole genome duplication (WGD) has occurred in relatively few sexually reproducing invertebrates. Consequently, the WGD that occurred in the common ancestor of horseshoe crabs ~135 million years ago provides a rare opportunity to decipher the evolutionary consequences of a duplicated invertebrate genome. Here, we present a high-quality genome assembly for the mangrove horseshoe crab Carcinoscorpius rotundicauda (1.7 Gb, N50 = 90.2 Mb, with 89.8% sequences anchored to 16 pseudomolecules, 2n = 32), and a resequenced genome of the tri-spine horseshoe crab Tachypleus tridentatus (1.7 Gb, N50 = 109.7 Mb). Analyses of gene families, microRNAs, and synteny show that horseshoe crabs have undergone three rounds (3R) of WGD. Comparison of C. rotundicauda and T. tridentatus genomes from populations from several geographic locations further elucidates the diverse fates of both coding and noncoding genes. Together, the present study represents a cornerstone for improving our understanding of invertebrate WGD events on the evolutionary fates of genes and microRNAs, at both the individual and population level. We also provide improved genomic resources for horseshoe crabs, of applied value for breeding programs and conservation of this fascinating and unusual invertebrate lineage.

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The chromosome-level genome of dragon fruit reveals whole-genome duplication and chromosomal co-localization of betacyanin biosynthetic genes

Horticulture Research ◽

10.1038/s41438-021-00501-6 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Jinfang Zheng ◽

Lyndel W. Meinhardt ◽

Ricardo Goenaga ◽

Dapeng Zhang ◽

Yanbin Yin

Keyword(s):

Whole Genome Duplication ◽

Plant Cell Wall ◽

Genome Duplication ◽

Draft Genome ◽

Gene Clusters ◽

Functional Enrichment ◽

Last Common Ancestor ◽

Whole Genome ◽

High Concentration ◽

Dragon Fruit

AbstractDragon fruits are tropical fruits economically important for agricultural industries. As members of the family of Cactaceae, they have evolved to adapt to the arid environment. Here we report the draft genome of Hylocereus undatus, commercially known as the white-fleshed dragon fruit. The chromosomal level genome assembly contains 11 longest scaffolds corresponding to the 11 chromosomes of H. undatus. Genome annotation of H. undatus found ~29,000 protein-coding genes, similar to Carnegiea gigantea (saguaro). Whole-genome duplication (WGD) analysis revealed a WGD event in the last common ancestor of Cactaceae followed by extensive genome rearrangements. The divergence time between H. undatus and C. gigantea was estimated to be 9.18 MYA. Functional enrichment analysis of orthologous gene clusters (OGCs) in six Cactaceae plants found significantly enriched OGCs in drought resistance. Fruit flavor-related functions were overrepresented in OGCs that are significantly expanded in H. undatus. The H. undatus draft genome also enabled the discovery of carbohydrate and plant cell wall-related functional enrichment in dragon fruits treated with trypsin for a longer storage time. Lastly, genes of the betacyanin (a red-violet pigment and antioxidant with a very high concentration in dragon fruits) biosynthetic pathway were found to be co-localized on a 12 Mb region of one chromosome. The consequence may be a higher efficiency of betacyanin biosynthesis, which will need experimental validation in the future. The H. undatus draft genome will be a great resource to study various cactus plants.

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The genome of the venomous snail Lautoconus ventricosus sheds light on the origin of conotoxin diversity

GigaScience ◽

10.1093/gigascience/giab037 ◽

2021 ◽

Vol 10 (5) ◽

Cited By ~ 1

Author(s):

José Ramón Pardos-Blas ◽

Iker Irisarri ◽

Samuel Abalde ◽

Carlos M L Afonso ◽

Manuel J Tenorio ◽

...

Keyword(s):

Whole Genome Duplication ◽

Genome Duplication ◽

Duplication Event ◽

Pomacea Canaliculata ◽

Whole Genome ◽

Genome Duplication Event ◽

Whole Genome Duplication Event ◽

Venomous Animals ◽

Genes Encoding ◽

Chromosome Level

Abstract Background Venoms are deadly weapons to subdue prey or deter predators that have evolved independently in many animal lineages. The genomes of venomous animals are essential to understand the evolutionary mechanisms involved in the origin and diversification of venoms. Results Here, we report the chromosome-level genome of the venomous Mediterranean cone snail, Lautoconus ventricosus (Caenogastropoda: Conidae). The total size of the assembly is 3.59 Gb; it has high contiguity (N50 = 93.53 Mb) and 86.6 Mb of the genome assembled into the 35 largest scaffolds or pseudochromosomes. On the basis of venom gland transcriptomes, we annotated 262 complete genes encoding conotoxin precursors, hormones, and other venom-related proteins. These genes were scattered in the different pseudochromosomes and located within repetitive regions. The genes encoding conotoxin precursors were normally structured into 3 exons, which did not necessarily coincide with the 3 structural domains of the corresponding proteins. Additionally, we found evidence in the L. ventricosus genome for a past whole-genome duplication event by means of conserved gene synteny with the Pomacea canaliculata genome, the only one available at the chromosome level within Caenogastropoda. The whole-genome duplication event was further confirmed by the presence of a duplicated hox gene cluster. Key genes for gastropod biology including those encoding proteins related to development, shell formation, and sex were located in the genome. Conclusions The new high-quality L. ventricosus genome should become a reference for assembling and analyzing new gastropod genomes and will contribute to future evolutionary genomic studies among venomous animals.

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Widespread retention of ohnologs in key developmental gene families following whole genome duplication in arachnopulmonates

G3 Genes|Genome|Genetics ◽

10.1093/g3journal/jkab299 ◽

2021 ◽

Author(s):

Amber Harper ◽

Luis Baudouin Gonzalez ◽

Anna Schönauer ◽

Ralf Janssen ◽

Michael Seiter ◽

...

Keyword(s):

Whole Genome Duplication ◽

Genome Duplication ◽

Genetic Material ◽

Gene Families ◽

Comparative Approach ◽

Whole Genome ◽

Animal Evolution ◽

Whole Genome Duplications ◽

Genome Duplications ◽

Horseshoe Crabs

Abstract Whole genome duplications have occurred multiple times during animal evolution, including in lineages leading to vertebrates, teleosts, horseshoe crabs and arachnopulmonates. These dramatic events initially produce a wealth of new genetic material, generally followed by extensive gene loss. It appears, however, that developmental genes such as homeobox genes, signalling pathway components and microRNAs are frequently retained as duplicates (so called ohnologs) following whole-genome duplication. These not only provide the best evidence for whole-genome duplication, but an opportunity to study its evolutionary consequences. Although these genes are well studied in the context of vertebrate whole-genome duplication, similar comparisons across the extant arachnopulmonate orders are patchy. We sequenced embryonic transcriptomes from two spider species and two amblypygid species and surveyed three important gene families, Hox, Wnt and frizzled, across these and twelve existing transcriptomic and genomic resources for chelicerates. We report extensive retention of putative ohnologs, further supporting the ancestral arachnopulmonate whole-genome duplication. We also found evidence of consistent evolutionary trajectories in Hox and Wnt gene repertoires across three of the six arachnopulmonate orders, with inter-order variation in the retention of specific paralogs. We identified variation between major clades in spiders and are better able to reconstruct the chronology of gene duplications and losses in spiders, amblypygids, and scorpions. These insights shed light on the evolution of the developmental toolkit in arachnopulmonates, highlight the importance of the comparative approach within lineages, and provide substantial new transcriptomic data for future study.

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Horseshoe crab genomes reveal the evolutionary fates of genes and microRNAs after three rounds (3R) of whole genome duplication

10.1101/2020.04.16.045815 ◽

2020 ◽

Cited By ~ 8

Author(s):

Wenyan Nong ◽

Zhe Qu ◽

Yiqian Li ◽

Tom Barton-Owen ◽

Annette Y.P. Wong ◽

...

Keyword(s):

Whole Genome Duplication ◽

Horseshoe Crab ◽

Genome Duplication ◽

Gene Families ◽

Whole Genome ◽

Breeding Programs ◽

Horseshoe Crabs ◽

The Common ◽

Evolutionary Consequences ◽

High Quality Genome

AbstractWhole genome duplication (WGD) has occurred in relatively few sexually reproducing invertebrates. Consequently, the WGD that occurred in the common ancestor of horseshoe crabs ~135 million years ago provides a rare opportunity to decipher the evolutionary consequences of a duplicated invertebrate genome. Here, we present a high-quality genome assembly for the mangrove horseshoe crab Carcinoscorpius rotundicauda (1.7Gb, N50 = 90.2Mb, with 89.8% sequences anchored to 16 pseudomolecules, 2n = 32), and a resequenced genome of the tri-spine horseshoe crab Tachypleus tridentatus (1.7Gb, N50 = 109.7Mb). Analyses of gene families, microRNAs, and synteny show that horseshoe crabs have undergone three rounds (3R) of WGD, and that these WGD events are shared with spiders. Comparison of the genomes of C. rotundicauda and T. tridentatus populations from several geographic locations further elucidates the diverse fates of both coding and noncoding genes. Together, the present study represents a cornerstone for a better understanding of the consequences of invertebrate WGD events on evolutionary fates of genes and microRNAs at individual and population levels, and highlights the genetic diversity with practical values for breeding programs and conservation of horseshoe crabs.

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