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Nie Y, Liu X, Zhao L, Huang Y. Repetitive element expansions contribute to genome size gigantism in Pamphagidae: A comparative study (Orthoptera, Acridoidea). Genomics 2024; 116:110896. [PMID: 39025318 DOI: 10.1016/j.ygeno.2024.110896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 07/10/2024] [Accepted: 07/15/2024] [Indexed: 07/20/2024]
Abstract
Pamphagidae is a family of Acridoidea that inhabits the desert steppes of Eurasia and Africa. This study employed flow cytometry to estimate the genome size of eight species in the Pamphagidae. The results indicate that the genome size of the eight species ranged from 13.88 pg to 14.66 pg, with an average of 14.26 pg. This is the largest average genome size recorded for the Orthoptera families, as well as for the entire Insecta. Furthermore, the study explored the role of repetitive sequences in the genome, including their evolutionary dynamics and activity, using low-coverage next-generation sequencing data. The genome is composed of 14 different types of repetitive sequences, which collectively make up between 59.9% and 68.17% of the total genome. The Pamphagidae family displays high levels of transposable element (TE) activity, with the number of TEs increasing and accumulating since the family's emergence. The study found that the types of repetitive sequences contributing to the TE outburst events are similar across species. Additionally, the study identified unique repetitive elements for each species. The differences in repetitive sequences among the eight Pamphagidae species correspond to their phylogenetic relationships. The study sheds new light on genome gigantism in the Pamphagidae and provides insight into the correlation between genome size and repetitive sequences within the family.
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Affiliation(s)
- Yimeng Nie
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Xuanzeng Liu
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Lina Zhao
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Yuan Huang
- College of Life Sciences, Shaanxi Normal University, Xi'an, China.
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2
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Khan H, Yuan H, Liu X, Nie Y, Majid M. Comprehensive analysis of the Xya riparia genome uncovers the dominance of DNA transposons, LTR/Gypsy elements, and their evolutionary dynamics. BMC Genomics 2024; 25:687. [PMID: 38997681 PMCID: PMC11245825 DOI: 10.1186/s12864-024-10596-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Accepted: 07/04/2024] [Indexed: 07/14/2024] Open
Abstract
Transposable elements (TEs) are DNA sequences that can move or replicate within a genome, and their study has become increasingly important in understanding genome evolution and function. The Tridactylidae family, including Xya riparia (pygmy mole cricket), harbors a variety of transposable elements (TEs) that have been insufficiently investigated. Further research is required to fully understand their diversity and evolutionary characteristics. Hence, we conducted a comprehensive repeatome analysis of X. riparia species using the chromosome-level assembled genome. The study aimed to comprehensively analyze the abundance, distribution, and age of transposable elements (TEs) in the genome. The results indicated that the genome was 1.67 Gb, with 731.63 Mb of repetitive sequences, comprising 27% of Class II (443.25 Mb), 16% of Class I (268.45 Mb), and 1% of unknown TEs (19.92 Mb). The study found that DNA transposons dominate the genome, accounting for approximately 60% of the total repeat size, with retrotransposons and unknown elements accounting for 37% and 3% of the genome, respectively. The members of the Gypsy superfamily were the most abundant amongst retrotransposons, accounting for 63% of them. The transposable superfamilies (LTR/Gypsy, DNA/nMITE, DNA/hAT, and DNA/Helitron) collectively constituted almost 70% of the total repeat size of all six chromosomes. The study further unveiled a significant linear correlation (Pearson correlation: r = 0.99, p-value = 0.00003) between the size of the chromosomes and the repetitive sequences. The average age of DNA transposon and retrotransposon insertions ranges from 25 My (million years) to 5 My. The satellitome analysis discovered 13 satellite DNA families that comprise about 0.15% of the entire genome. In addition, the transcriptional analysis of TEs found that DNA transposons were more transcriptionally active than retrotransposons. Overall, the study suggests that the genome of X. riparia is complex, characterized by a substantial portion of repetitive elements. These findings not only enhance our understanding of TE evolution within the Tridactylidae family but also provide a foundation for future investigations into the genomic intricacies of related species.
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Affiliation(s)
- Hashim Khan
- College of Life Sciences, Shaanxi Normal University, Xian, China
| | - Huang Yuan
- College of Life Sciences, Shaanxi Normal University, Xian, China
| | - Xuanzeng Liu
- College of Life Sciences, Shaanxi Normal University, Xian, China
| | - Yimeng Nie
- College of Life Sciences, Shaanxi Normal University, Xian, China
| | - Muhammad Majid
- College of Life Sciences, Shaanxi Normal University, Xian, China.
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Jing X, Zhao HY, Zheng YN, Nie YM, Ma LB, Huang Y. A Chromosome-Level Genome Assembly and Annotation for the Oecanthus rufescens (Orthoptera: Oecanthidae). Genome Biol Evol 2024; 16:evae145. [PMID: 38946321 PMCID: PMC11243396 DOI: 10.1093/gbe/evae145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 06/11/2024] [Accepted: 06/25/2024] [Indexed: 07/02/2024] Open
Abstract
Oecanthus is a genus of cricket known for its distinctive chirping and distributed across major zoogeographical regions worldwide. This study focuses on Oecanthus rufescens, and conducts a comprehensive examination of its genome through genome sequencing technologies and bioinformatic analysis. A high-quality chromosome-level genome of O. rufescens was successfully obtained, revealing significant features of its genome structure. The genome size is 877.9 Mb, comprising ten pseudo-chromosomes and 70 other sequences, with a GC content of 41.38% and an N50 value of 157,110,771 bp, indicating a high level of continuity. BUSCO assessment results demonstrate that the genome's integrity and quality are high (of which 96.8% are single-copy and 1.6% are duplicated). Comprehensive genome annotation was also performed, identifying approximately 310 Mb of repetitive sequences, accounting for 35.3% of the total genome sequence, and discovering 15,481 tRNA genes, 4,082 rRNA genes, and 1,212 other noncoding genes. Furthermore, 15,031 protein-coding genes were identified, with BUSCO assessment results showing that 98.4% (of which 96.3% are single-copy and 1.6% are duplicated) of the genes were annotated.
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Affiliation(s)
- Xuan Jing
- College of Life Sciences, Shaanxi Normal University, 710119 Xi’an, China
| | - Hui-Yao Zhao
- College of Life Sciences, Shaanxi Normal University, 710119 Xi’an, China
| | - Yan-Na Zheng
- College of Life Sciences, Shaanxi Normal University, 710119 Xi’an, China
| | - Yi-Meng Nie
- College of Life Sciences, Shaanxi Normal University, 710119 Xi’an, China
| | - Li-Bin Ma
- College of Life Sciences, Shaanxi Normal University, 710119 Xi’an, China
| | - Yuan Huang
- College of Life Sciences, Shaanxi Normal University, 710119 Xi’an, China
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Chang H, Liu X, Xie Z. The complete mitochondrial genome of Phymateus saxosus (Coquerel, 1861) (Orthoptera: Pyrgomorphidae) and phylogenetic analysis. Mitochondrial DNA B Resour 2024; 9:457-460. [PMID: 38591051 PMCID: PMC11000610 DOI: 10.1080/23802359.2024.2316064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 02/03/2024] [Indexed: 04/10/2024] Open
Abstract
Phymateus saxosus is a member of the family Pyrgomorphidae, Orthoptera. In this study, the complete mitochondrial genome (mitogenome) of P. saxosus was determined and analyzed. Assembled mitogenome sequence of P. saxosus is 15,672 bp in size, containing 37 genes and a control region. The gene orientation and arrangement of P. saxosus are identical to other species in the Pyrgomorphoidea family. The overall nucleotide composition is as follows: A (43.6%) > T (30.2%) > C (16.1%) > G (10.1%). Phylogenetic analysis suggested that P. saxosus forms sister groups with P. morbillosus, and the monophyly of Pyrgomorphidae is supported. In general, this study provided valuable genetic information for P. saxosus and explored the phylogenetic relationships in the family Pyrgomorphidae.
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Affiliation(s)
- Huihui Chang
- College of Life Sciences and Engineering, Henan University of Urban Construction, Pingdingshan, Henan, China
| | - Xinhu Liu
- School of Energy and Building Environment Engineering, Henan University of Urban Construction, Pingdingshan, Henan, China
| | - Zhaohui Xie
- CONTACT Zhaohui Xie College of Life Sciences and Engineering, Henan University of Urban Construction, Pingdingshan, Henan467036, China
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Liu X, Zhao L, Majid M, Huang Y. Orthoptera-TElib: a library of Orthoptera transposable elements for TE annotation. Mob DNA 2024; 15:5. [PMID: 38486291 PMCID: PMC10941475 DOI: 10.1186/s13100-024-00316-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 03/08/2024] [Indexed: 03/17/2024] Open
Abstract
Transposable elements (TEs) are a major component of eukaryotic genomes and are present in almost all eukaryotic organisms. TEs are highly dynamic between and within species, which significantly affects the general applicability of the TE databases. Orthoptera is the only known group in the class Insecta with a significantly enlarged genome (0.93-21.48 Gb). When analyzing the large genome using the existing TE public database, the efficiency of TE annotation is not satisfactory. To address this limitation, it becomes imperative to continually update the available TE resource library and the need for an Orthoptera-specific library as more insect genomes are publicly available. Here, we used the complete genome data of 12 Orthoptera species to de novo annotate TEs, then manually re-annotate the unclassified TEs to construct a non-redundant Orthoptera-specific TE library: Orthoptera-TElib. Orthoptera-TElib contains 24,021 TE entries including the re-annotated results of 13,964 unknown TEs. The naming of TE entries in Orthoptera-TElib adopts the same naming as RepeatMasker and Dfam and is encoded as the three-level form of "level1/level2-level3". Orthoptera-TElib can be directly used as an input reference database and is compatible with mainstream repetitive sequence analysis software such as RepeatMasker and dnaPipeTE. When analyzing TEs of Orthoptera species, Orthoptera-TElib performs better TE annotation as compared to Dfam and Repbase regardless of using low-coverage sequencing or genome assembly data. The most improved TE annotation result is Angaracris rhodopa, which has increased from 7.89% of the genome to 53.28%. Finally, Orthoptera-TElib is stored in Sqlite3 for the convenience of data updates and user access.
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Affiliation(s)
- Xuanzeng Liu
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Lina Zhao
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Muhammad Majid
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Yuan Huang
- College of Life Sciences, Shaanxi Normal University, Xi'an, China.
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Genome Survey Sequencing of the Mole Cricket Gryllotalpa orientalis. Genes (Basel) 2023; 14:genes14020255. [PMID: 36833184 PMCID: PMC9957284 DOI: 10.3390/genes14020255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/05/2023] [Accepted: 01/13/2023] [Indexed: 01/20/2023] Open
Abstract
The mole cricket Gryllotalpa orientalis is an evolutionarily, medicinal, and agriculturally significant insect that inhabits underground environments and is distributed globally. This study measured genome size by flow cytometry and k-mer based on low-coverage sequencing, and nuclear repetitive elements were also identified. The haploid genome size estimate is 3.14 Gb by flow cytometry, 3.17 Gb, and 3.77 Gb-based two k-mer methods, respectively, which is well within the range previously reported for other species of the suborder Ensifera. 56% of repetitive elements were found in G. orientalis, similar to 56.83% in Locusta migratoria. However, the great size of repetitive sequences could not be annotated to specific repeat element families. For the repetitive elements that were annotated, Class I-LINE retrotransposon elements were the most common families and more abundant than satellite and Class I-LTR. These results based on the newly developed genome survey could be used in the taxonomic study and whole genome sequencing to improve the understanding of the biology of G. orientalis.
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Liu X, Majid M, Yuan H, Chang H, Zhao L, Nie Y, He L, Liu X, He X, Huang Y. Transposable element expansion and low-level piRNA silencing in grasshoppers may cause genome gigantism. BMC Biol 2022; 20:243. [PMID: 36307800 PMCID: PMC9615261 DOI: 10.1186/s12915-022-01441-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 10/17/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Transposable elements (TEs) have been likened to parasites in the genome that reproduce and move ceaselessly in the host, continuously enlarging the host genome. However, the Piwi-interacting RNA (piRNA) pathway defends animal genomes against the harmful consequences of TE invasion by imposing small-RNA-mediated silencing. Here we compare the TE activity of two grasshopper species with different genome sizes in Acrididae (Locusta migratoria manilensis♀1C = 6.60 pg, Angaracris rhodopa♀1C = 16.36 pg) to ascertain the influence of piRNAs.
Results
We discovered that repetitive sequences accounted for 74.56% of the genome in A. rhodopa, more than 56.83% in L. migratoria, and the large-genome grasshopper contained a higher TEs proportions. The comparative analysis revealed that 41 TEs (copy number > 500) were shared in both species. The two species exhibited distinct “landscapes” of TE divergence. The TEs outbreaks in the small-genome grasshopper occurred at more ancient times, while the large-genome grasshopper maintains active transposition events in the recent past. Evolutionary history studies on TEs suggest that TEs may be subject to different dynamics and resistances in these two species. We found that TE transcript abundance was higher in the large-genome grasshopper and the TE-derived piRNAs abundance was lower than in the small-genome grasshopper. In addition, we found that the piRNA methylase HENMT, which is underexpressed in the large-genome grasshopper, impedes the piRNA silencing to a lower level.
Conclusions
Our study revealed that the abundance of piRNAs is lower in the gigantic genome grasshopper than in the small genome grasshopper. In addition, the key gene HENMT in the piRNA biogenesis pathway (Ping-Pong cycle) in the gigantic genome grasshopper is underexpressed. We hypothesize that low-level piRNA silencing unbalances the original positive correlation between TEs and piRNAs, and triggers TEs to proliferate out of control, which may be one of the reasons for the gigantism of grasshopper genomes.
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Timm VF, Gonçalves LT, Valente V, Deprá M. The efficiency of the COI gene as a DNA barcode and an overview of Orthoptera (Caelifera and Ensifera) sequences in the BOLD System. CAN J ZOOL 2022. [DOI: 10.1139/cjz-2022-0041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Orthoptera, among the oldest and most numerous insect lineages, is an excellent model for evolutionary studies but has numerous taxonomic problems. To mitigate these issues, the cytochrome c oxidase subunit I (COI), standardized with the DNA barcode for Metazoa, is increasingly used for specimen identification and species delimitation. We tested the performance of COI as a DNA barcode in Orthoptera, using two analyses based on intra- and interspecific distances, barcode gap and Probability of Correct Identification (PCI); and estimated species richness through Automatic Barcode Gap Discovery (ABGD) and Assemble Species by Automatic Partitioning (ASAP). We filtered all sequences of Orthoptera available in Barcode of Life Data System (BOLD) and used 11,605 COI sequences, covering 1,132 species, 226 genera, and 18 families. The overall average PCI was 73.86%. For 82.2% of genera the barcode gap boxplots were classified as good or intermediate, indicating that COI can be effective as a DNA barcode in Orthoptera, although with varying efficiency depending on the need for more information. ABGD and ASAP inferred species richness similar to labels informed by BOLD for the suborders Caelifera and Ensifera. The representation of Orthoptera in the BOLD database and the results of these analyses are discussed.
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Affiliation(s)
- Vítor Falchi Timm
- Universidade Federal do Rio Grande do Sul, 28124, Departamento de Genética, Porto Alegre, RS, Brazil
| | | | - V.l.S. Valente
- Universidade Federal do Rio Grande do Sul, 28124, Departamento de Genética, Porto Alegre, RS, Brazil,
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Kornaliková M, Hampl V, Treitli SC. Investigation of the Genome Sizes and Ploidy Within the Genus
Monocercomonoides. J Eukaryot Microbiol 2022; 69:e12925. [DOI: 10.1111/jeu.12925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Martina Kornaliková
- Department of Parasitology, Faculty of Science Charles University, BIOCEV Vestec Czech Republic
| | - Vladimir Hampl
- Department of Parasitology, Faculty of Science Charles University, BIOCEV Vestec Czech Republic
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10
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Husemann M, Dey LS, Sadílek D, Ueshima N, Hawlitschek O, Song H, Weissman DB. Evolution of chromosome number in grasshoppers (Orthoptera: Caelifera: Acrididae). ORG DIVERS EVOL 2022. [DOI: 10.1007/s13127-022-00543-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
AbstractOrthoptera have some of the largest genomes of all insects. At the same time, the architecture of their genomes remains poorly understood. Comparative cytological data across a wide range of taxa, even for basic parameters such as chromosome number, may provide important insights into the evolution of these genomes and help answer the question of why some species attained such large sizes. We collected and compiled more than 1,000 records of chromosome numbers of 339 genera (13.8% of 2,452 known genera) and 769 species (6.2% of 12,250 known species) of Caelifera, the suborder of Orthoptera that includes those taxa with short antennae. Within the family Acrididae, most of the records come from the subfamilies Oedipodinae (N = 325), Melanoplinae (N = 192) and Gomphocerinae (N = 254). Out of the 621 investigated species of Acrididae, 459 (73.9%) shared a chromosome number of 2n♂ = 23. Chromosome numbers of 2n♂ = 17 (12.2%) and 2n♂ = 21 (9.9%) were less common. The remaining 4.0% of species exhibited different chromosome numbers between 2n♂ = 8 (6 + XY) and 2n♂ = 27. Plotted on a phylogenetic tree, our results confirm that chromosome numbers, especially in the largest grasshopper family Acrididae, are highly conserved with a basic count of 2n♂ = 23 (22 + X0), sometimes reduced to, e.g., 2n♂ = 17 (16 + X0) in some genera of the slant-faced grasshopper subfamily Gomphocerinae. Species with divergent chromosome numbers occur in many of the groups we studied, but are not a systematic trait and have evolved multiple times independently. Our study supports the view that chromosome numbers are much more stable across the investigated Caelifera compared to Ensifera, the second suborder of Orthoptera that includes the long antennae bush crickets and crickets. Our results significantly extend our knowledge on the diversity of this character in Caelifera.
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11
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Galla SJ, Brown L, Couch-Lewis Ngāi Tahu Te Hapū O Ngāti Wheke Ngāti Waewae Y, Cubrinovska I, Eason D, Gooley RM, Hamilton JA, Heath JA, Hauser SS, Latch EK, Matocq MD, Richardson A, Wold JR, Hogg CJ, Santure AW, Steeves TE. The relevance of pedigrees in the conservation genomics era. Mol Ecol 2021; 31:41-54. [PMID: 34553796 PMCID: PMC9298073 DOI: 10.1111/mec.16192] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/12/2021] [Accepted: 09/17/2021] [Indexed: 01/21/2023]
Abstract
Over the past 50 years conservation genetics has developed a substantive toolbox to inform species management. One of the most long‐standing tools available to manage genetics—the pedigree—has been widely used to characterize diversity and maximize evolutionary potential in threatened populations. Now, with the ability to use high throughput sequencing to estimate relatedness, inbreeding, and genome‐wide functional diversity, some have asked whether it is warranted for conservation biologists to continue collecting and collating pedigrees for species management. In this perspective, we argue that pedigrees remain a relevant tool, and when combined with genomic data, create an invaluable resource for conservation genomic management. Genomic data can address pedigree pitfalls (e.g., founder relatedness, missing data, uncertainty), and in return robust pedigrees allow for more nuanced research design, including well‐informed sampling strategies and quantitative analyses (e.g., heritability, linkage) to better inform genomic inquiry. We further contend that building and maintaining pedigrees provides an opportunity to strengthen trusted relationships among conservation researchers, practitioners, Indigenous Peoples, and Local Communities.
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Affiliation(s)
- Stephanie J Galla
- Department of Biological Sciences, Boise State University, Boise, Idaho, USA.,School of Biological Sciences, University of Canterbury, Christchurch, Canterbury, New Zealand
| | - Liz Brown
- New Zealand Department of Conservation, Twizel, Canterbury, New Zealand
| | | | - Ilina Cubrinovska
- School of Biological Sciences, University of Canterbury, Christchurch, Canterbury, New Zealand
| | - Daryl Eason
- New Zealand Department of Conservation, Invercargill, Southland, New Zealand
| | - Rebecca M Gooley
- Smithsonian-Mason School of Conservation, Front Royal, Maryland, USA.,Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, District of Columbia, USA
| | - Jill A Hamilton
- Department of Biological Sciences, North Dakota State University, Fargo, North Dakota, USA
| | - Julie A Heath
- Department of Biological Sciences, Boise State University, Boise, Idaho, USA
| | - Samantha S Hauser
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Emily K Latch
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Marjorie D Matocq
- Department of Natural Resources and Environmental Science, Program in Ecology, Evolution and Conservation Biology, University of Nevada Reno, Reno, Nevada, USA
| | - Anne Richardson
- The Isaac Conservation and Wildlife Trust, Christchurch, Canterbury, New Zealand
| | - Jana R Wold
- School of Biological Sciences, University of Canterbury, Christchurch, Canterbury, New Zealand
| | - Carolyn J Hogg
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia
| | - Anna W Santure
- School of Biological Sciences, University of Auckland, Auckland, Auckland, New Zealand
| | - Tammy E Steeves
- School of Biological Sciences, University of Canterbury, Christchurch, Canterbury, New Zealand
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Comparative Analysis of Transposable Elements in Genus Calliptamus Grasshoppers Revealed That Satellite DNA Contributes to Genome Size Variation. INSECTS 2021; 12:insects12090837. [PMID: 34564277 PMCID: PMC8466570 DOI: 10.3390/insects12090837] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/01/2021] [Accepted: 09/14/2021] [Indexed: 12/15/2022]
Abstract
Simple Summary Calliptamus is a genus of grasshoppers belonging to the family Acrididae. The genus Calliptamus includes approximately 17 recognized species. Calliptamus abbreviatus, Calliptamus italicus, and Calliptamus barbarus are three species that are widely found in northern China. These species are polyphagous, feeding on a variety of wild plants as well as crops, particularly legumes. The genome sizes, phylogenetic position, and transcriptome analysis of the genus Calliptamus were already known previous to this research. The repeatome analysis of these species was missing, which is directly linked to the larger genome sizes of the grasshoppers. Here, we classified repetitive DNA sequences at the level of superfamilies and sub-families, and found that LINE, TcMar-Tc1 and Ty3-gypsy LTR retrotransposons dominated the repeatomes of all genomes, accounting for 16–34% of the total genomes of these species. Satellite DNA dynamic evolutionary changes in all three genomes played a role in genome size evolution. This study would be a valuable source for future genome assemblies. Abstract Transposable elements (TEs) play a significant role in both eukaryotes and prokaryotes genome size evolution, structural changes, duplication, and functional variabilities. However, the large number of different repetitive DNA has hindered the process of assembling reference genomes, and the genus level TEs diversification of the grasshopper massive genomes is still under investigation. The genus Calliptamus diverged from Peripolus around 17 mya and its species divergence dated back about 8.5 mya, but their genome size shows rather large differences. Here, we used low-coverage Illumina unassembled short reads to investigate the effects of evolutionary dynamics of satDNAs and TEs on genome size variations. The Repeatexplorer2 analysis with 0.5X data resulted in 52%, 56%, and 55% as repetitive elements in the genomes of Calliptamus barbarus, Calliptamus italicus, and Calliptamus abbreviatus, respectively. The LINE and Ty3-gypsy LTR retrotransposons and TcMar-Tc1 dominated the repeatomes of all genomes, accounting for 16–35% of the total genomes of these species. Comparative analysis unveiled that most of the transposable elements (TEs) except satDNAs were highly conserved across three genomes in the genus Calliptamus grasshoppers. Out of a total of 20 satDNA families, 17 satDNA families were commonly shared with minor variations in abundance and divergence between three genomes, and 3 were Calliptamus barbarus specific. Our findings suggest that there is a significant amplification or contraction of satDNAs at genus phylogeny which is the main cause that made genome size different.
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Yuan H, Huang Y, Mao Y, Zhang N, Nie Y, Zhang X, Zhou Y, Mao S. The Evolutionary Patterns of Genome Size in Ensifera (Insecta: Orthoptera). Front Genet 2021; 12:693541. [PMID: 34249107 PMCID: PMC8261143 DOI: 10.3389/fgene.2021.693541] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 05/25/2021] [Indexed: 11/13/2022] Open
Abstract
Genomic size variation has long been a focus for biologists. However, due to the lack of genome size data, the mechanisms behind this variation and the biological significance of insect genome size are rarely studied systematically. The detailed taxonomy and phylogeny of the Ensifera, as well as the extensive documentation concerning their morphological, ecological, behavioral, and distributional characteristics, make them a strong model for studying the important scientific problem of genome size variation. However, data on the genome size of Ensifera are rather sparse. In our study, we used flow cytometry to determine the genome size of 32 species of Ensifera, the smallest one being only 1C = 0.952 pg with the largest species up to 1C = 19.135 pg, representing a 20-fold range. This provides a broader blueprint for the genome size variation of Orthoptera than was previously available. We also completed the assembly of nine mitochondrial genomes and combined mitochondrial genome data from public databases to construct phylogenetic trees containing 32 species of Ensifera and three outgroups. Based on these inferred phylogenetic trees, we detected the phylogenetic signal of genome size variation in Ensifera and found that it was strong in both males and females. Phylogenetic comparative analyses revealed that there were no correlations between genome size and body size or flight ability in Tettigoniidae. Reconstruction of ancestral genome size revealed that the genome size of Ensifera evolved in a complex pattern, in which the genome size of the grylloid clade tended to decrease while that of the non-grylloid clade expanded significantly albeit with fluctuations. However, the evolutionary mechanisms underlying variation of genome size in Ensifera are still unknown.
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Affiliation(s)
- Hao Yuan
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Yuan Huang
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Ying Mao
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Nan Zhang
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Yimeng Nie
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Xue Zhang
- College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Yafu Zhou
- Xi'an Botanical Garden of Shaanxi Province/Institute of Botany of Shaanxi Province, Shaanxi Engineering Research Centre for Conservation and Utilization of Botanical Resources, Xi'an, China
| | - Shaoli Mao
- Xi'an Botanical Garden of Shaanxi Province/Institute of Botany of Shaanxi Province, Shaanxi Engineering Research Centre for Conservation and Utilization of Botanical Resources, Xi'an, China
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