1
|
Miles LS, Waterman H, Ayoub NA, Garb JE, Haney RA, Rosenberg MS, Krabbenhoft TJ, Verrelli BC. Insight into the adaptive role of arachnid genome-wide duplication through chromosome-level genome assembly of the Western black widow spider. J Hered 2024; 115:241-252. [PMID: 38567866 DOI: 10.1093/jhered/esae018] [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: 12/01/2023] [Accepted: 03/19/2024] [Indexed: 05/12/2024] Open
Abstract
Although spiders are one of the most diverse groups of arthropods, the genetic architecture of their evolutionary adaptations is largely unknown. Specifically, ancient genome-wide duplication occurring during arachnid evolution ~450 mya resulted in a vast assembly of gene families, yet the extent to which selection has shaped this variation is understudied. To aid in comparative genome sequence analyses, we provide a chromosome-level genome of the Western black widow spider (Latrodectus hesperus)-a focus due to its silk properties, venom applications, and as a model for urban adaptation. We used long-read and Hi-C sequencing data, combined with transcriptomes, to assemble 14 chromosomes in a 1.46 Gb genome, with 38,393 genes annotated, and a BUSCO score of 95.3%. Our analyses identified high repetitive gene content and heterozygosity, consistent with other spider genomes, which has led to challenges in genome characterization. Our comparative evolutionary analyses of eight genomes available for species within the Araneoidea group (orb weavers and their descendants) identified 1,827 single-copy orthologs. Of these, 155 exhibit significant positive selection primarily associated with developmental genes, and with traits linked to sensory perception. These results support the hypothesis that several traits unique to spiders emerged from the adaptive evolution of ohnologs-or retained ancestrally duplicated genes-from ancient genome-wide duplication. These comparative spider genome analyses can serve as a model to understand how positive selection continually shapes ancestral duplications in generating novel traits today within and between diverse taxonomic groups.
Collapse
Affiliation(s)
- Lindsay S Miles
- Center for Biological Data Science, Virginia Commonwealth University, Richmond, VA, United States
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Hannah Waterman
- Department of Biological Sciences and Research and Education in Energy, Environment, and Water Institute, University at Buffalo, Buffalo, NY, United States
| | - Nadia A Ayoub
- Department of Biology, Washington and Lee University, Lexington, VA, United States
| | - Jessica E Garb
- Department of Biological Sciences, University of Massachusetts Lowell, Lowell, MA, United States
| | - Robert A Haney
- Department of Biology, Ball State University, Muncie, IN, United States
| | - Michael S Rosenberg
- Center for Biological Data Science, Virginia Commonwealth University, Richmond, VA, United States
| | - Trevor J Krabbenhoft
- Department of Biological Sciences and Research and Education in Energy, Environment, and Water Institute, University at Buffalo, Buffalo, NY, United States
| | - Brian C Verrelli
- Center for Biological Data Science, Virginia Commonwealth University, Richmond, VA, United States
| |
Collapse
|
2
|
Correa-Garhwal SM, Baker RH, Clarke TH, Ayoub NA, Hayashi CY. The evolutionary history of cribellate orb-weaver capture thread spidroins. BMC Ecol Evol 2022; 22:89. [PMID: 35810286 PMCID: PMC9270836 DOI: 10.1186/s12862-022-02042-5] [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: 08/02/2021] [Accepted: 06/21/2022] [Indexed: 11/19/2022] Open
Abstract
Background Spiders have evolved two types of sticky capture threads: one with wet adhesive spun by ecribellate orb-weavers and another with dry adhesive spun by cribellate spiders. The evolutionary history of cribellate capture threads is especially poorly understood. Here, we use genomic approaches to catalog the spider-specific silk gene family (spidroins) for the cribellate orb-weaver Uloborus diversus. Results We show that the cribellar spidroin, which forms the puffy fibrils of cribellate threads, has three distinct repeat units, one of which is conserved across cribellate taxa separated by ~ 250 Mya. We also propose candidates for a new silk type, paracribellar spidroins, which connect the puffy fibrils to pseudoflagelliform support lines. Moreover, we describe the complete repeat architecture for the pseudoflagelliform spidroin (Pflag), which contributes to extensibility of pseudoflagelliform axial fibers. Conclusions Our finding that Pflag is closely related to Flag, supports homology of the support lines of cribellate and ecribellate capture threads. It further suggests an evolutionary phase following gene duplication, in which both Flag and Pflag were incorporated into the axial lines, with subsequent loss of Flag in uloborids, and increase in expression of Flag in ecribellate orb-weavers, explaining the distinct mechanical properties of the axial lines of these two groups. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-022-02042-5.
Collapse
|
3
|
Egg Case Protein 3: A Constituent of Black Widow Spider Tubuliform Silk. Molecules 2021; 26:molecules26165088. [PMID: 34443676 PMCID: PMC8399404 DOI: 10.3390/molecules26165088] [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: 07/31/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 11/17/2022] Open
Abstract
Spider silk has outstanding mechanical properties, rivaling some of the best materials on the planet. Biochemical analyses of tubuliform silk have led to the identification of TuSp1, egg case protein 1, and egg case protein 2. TuSp1 belongs to the spidroin superfamily, containing a non-repetitive N- and C-terminal domain and internal block repeats. ECP1 and ECP2, which lack internal block repeats and sequence similarities to the highly conserved N- and C-terminal domains of spidroins, have cysteine-rich N-terminal domains. In this study, we performed an in-depth proteomic analysis of tubuliform glands, spinning dope, and egg sacs, which led to the identification of a novel molecular constituent of black widow tubuliform silk, referred to as egg case protein 3 or ECP3. Analysis of the translated ECP3 cDNA predicts a low molecular weight protein of 11.8 kDa. Real-time reverse transcription–quantitative PCR analysis performed with different silk-producing glands revealed ECP3 mRNA is predominantly expressed within tubuliform glands of spiders. Taken together, these findings reveal a novel protein that is secreted into black widow spider tubuliform silk.
Collapse
|
4
|
Chaw RC, Clarke TH, Arensburger P, Ayoub NA, Hayashi CY. Gene expression profiling reveals candidate genes for defining spider silk gland types. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2021; 135:103594. [PMID: 34052321 DOI: 10.1016/j.ibmb.2021.103594] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 05/11/2021] [Accepted: 05/13/2021] [Indexed: 06/12/2023]
Abstract
Molecular studies of the secretory glands involved in spider silk production have revealed candidate genes for silk synthesis and a complicated history of spider silk gene evolution. However, differential gene expression profiles of the multiple silk gland types within an individual orb-web weaving spider are lacking. Each of these gland types produces a functionally distinct silk type. Comparison of gene expression among spider silk gland types would provide insight into the genes that define silk glands generally from non-silk gland tissues, and the genes that define silk glands from each other. Here, we perform 3' tag digital gene expression profiling of the seven silk gland types of the silver garden orb weaver Argiope argentata. Five of these gland types produce silks that are non-adhesive fibers, one silk includes both fibers and glue-like adhesives, and one silk is exclusively glue-like. We identify 1275 highly expressed, significantly upregulated, and tissue specific silk gland specific transcripts (SSTs). These SSTs include seven types of spider silk protein encoding genes known as spidroin genes. We find that the fiber-producing major ampullate and minor ampullate silk glands have more similar expression profiles than any other pair of glands. We also find that a subset of the SSTs is enriched for transmembrane transport and oxidoreductases, and that these transcripts highlight differences and similarities among the major ampullate, minor ampullate, and aggregate silk glands. Furthermore, we show that the wet glue-producing aggregate glands have the most unique SSTs, but still share some SSTs with fiber producing glands. Aciniform glands were the only gland type to share a majority of SSTs with other silk gland types, supporting previous hypotheses that duplication of aciniform glands and subsequent divergence of the duplicates gave rise to the multiple silk gland types within an individual spider.
Collapse
Affiliation(s)
- R Crystal Chaw
- University of California, Riverside, Department of Evolution, Ecology, and Organismal Biology, 2710 Life Science Building, Riverside, CA, 92521, USA.
| | - Thomas H Clarke
- Washington and Lee University, Department of Biology, Howe Hall, Lexington, VA, 24450, USA.
| | - Peter Arensburger
- Department of Biological Sciences, California State Polytechnic University, Pomona, CA, 91768, USA.
| | - Nadia A Ayoub
- Washington and Lee University, Department of Biology, Howe Hall, Lexington, VA, 24450, USA.
| | - Cheryl Y Hayashi
- University of California, Riverside, Department of Evolution, Ecology, and Organismal Biology, 2710 Life Science Building, Riverside, CA, 92521, USA.
| |
Collapse
|
5
|
Berger CA, Brewer MS, Kono N, Nakamura H, Arakawa K, Kennedy SR, Wood HM, Adams SA, Gillespie RG. Shifts in morphology, gene expression, and selection underlie web loss in Hawaiian Tetragnatha spiders. BMC Ecol Evol 2021; 21:48. [PMID: 33752590 PMCID: PMC7983290 DOI: 10.1186/s12862-021-01779-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 03/10/2021] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND A striking aspect of evolution is that it often converges on similar trajectories. Evolutionary convergence can occur in deep time or over short time scales, and is associated with the imposition of similar selective pressures. Repeated convergent events provide a framework to infer the genetic basis of adaptive traits. The current study examines the genetic basis of secondary web loss within web-building spiders (Araneoidea). Specifically, we use a lineage of spiders in the genus Tetragnatha (Tetragnathidae) that has diverged into two clades associated with the relatively recent (5 mya) colonization of, and subsequent adaptive radiation within, the Hawaiian Islands. One clade has adopted a cursorial lifestyle, and the other has retained the ancestral behavior of capturing prey with sticky orb webs. We explore how these behavioral phenotypes are reflected in the morphology of the spinning apparatus and internal silk glands, and the expression of silk genes. Several sister families to the Tetragnathidae have undergone similar web loss, so we also ask whether convergent patterns of selection can be detected in these lineages. RESULTS The cursorial clade has lost spigots associated with the sticky spiral of the orb web. This appears to have been accompanied by loss of silk glands themselves. We generated phylogenies of silk proteins (spidroins), which showed that the transcriptomes of cursorial Tetragnatha contain all major spidroins except for flagelliform. We also found an uncharacterized spidroin that has higher expression in cursorial species. We found evidence for convergent selection acting on this spidroin, as well as genes involved in protein metabolism, in the cursorial Tetragnatha and divergent cursorial lineages in the families Malkaridae and Mimetidae. CONCLUSIONS Our results provide strong evidence that independent web loss events and the associated adoption of a cursorial lifestyle are based on similar genetic mechanisms. Many genes we identified as having evolved convergently are associated with protein synthesis, degradation, and processing, which are processes that play important roles in silk production. This study demonstrates, in the case of independent evolution of web loss, that similar selective pressures act on many of the same genes to produce the same phenotypes and behaviors.
Collapse
Affiliation(s)
- Cory A Berger
- Department of Environmental Science, Policy and Management, University of California, Berkeley, 130 Mulford Hall, #3114, Berkeley, CA, 94720-3114, USA.
- MIT-WHOI Joint Program in Oceanography/Applied Ocean Science and Engineering, Cambridge, Woods Hole, MA, USA.
| | - Michael S Brewer
- Department of Biology, N1088 Howell Science Complex, East Carolina University, Greenville, NC, 27858, USA
| | - Nobuaki Kono
- Institute for Advanced Biosciences, Keio University, Yamagata, Japan
| | - Hiroyuki Nakamura
- Enzyme Research Team, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan
| | - Kazuharu Arakawa
- Institute for Advanced Biosciences, Keio University, Yamagata, Japan
| | - Susan R Kennedy
- Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Tancha 1919-1, Onna, Okinawa, 904-0495, Japan
| | - Hannah M Wood
- Smithsonian Institution, Entomology, MRC105, Natural History Bldg. E519, 1000 Constitution Ave NW, Washington DC, 20560-0188, USA
| | - Seira A Adams
- Department of Environmental Science, Policy and Management, University of California, Berkeley, 130 Mulford Hall, #3114, Berkeley, CA, 94720-3114, USA
| | - Rosemary G Gillespie
- Department of Environmental Science, Policy and Management, University of California, Berkeley, 130 Mulford Hall, #3114, Berkeley, CA, 94720-3114, USA
| |
Collapse
|
6
|
Shanafelt M, Rabara T, MacArt D, Williams C, Hekman R, Joo H, Tsai J, Vierra C. Structural Characterization of Black Widow Spider Dragline Silk Proteins CRP1 and CRP4. Molecules 2020; 25:molecules25143212. [PMID: 32674428 PMCID: PMC7397007 DOI: 10.3390/molecules25143212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 07/03/2020] [Accepted: 07/10/2020] [Indexed: 01/30/2023] Open
Abstract
Spider dragline silk represents a biomaterial with outstanding mechanical properties, possessing high-tensile strength and toughness. In black widows at least eight different proteins have been identified as constituents of dragline silk. These represent major ampullate spidroins MaSp1, MaSp2, MaSp’, and several low-molecular weight cysteine-rich protein (CRP) family members, including CRP1, CRP2, and CRP4. Molecular modeling predicts that CRPs contain a cystine slipknot motif, but experimental evidence to support this assertion remains to be reported. To advance scientific knowledge regarding CRP function, we recombinantly expressed and purified CRP1 and CRP4 from bacteria and investigated their secondary structure using circular dichroism (CD) under different chemical and physical conditions. We demonstrate by far-UV CD spectroscopy that these proteins contain similar secondary structure, having substantial amounts of random coil conformation, followed by lower levels of beta sheet, alpha helical and beta turn structures. CRPs are thermally and pH stable; however, treatment with reagents that disrupt disulfide bonds impact their structural conformations. Cross-linking mass spectrometry (XL-MS) data also support computational models of CRP1. Taken together, the chemical and thermal stability of CRPs, the cross-linking data, coupled with the structural sensitivity to reducing agents, are experimentally consistent with the supposition CRPs are cystine slipknot proteins.
Collapse
Affiliation(s)
- Mikayla Shanafelt
- Departments of Chemistry and Biological Sciences, University of the Pacific, Stockton, CA 95211, USA; (M.S.); (T.R.); (D.M.); (H.J.); (J.T.)
| | - Taylor Rabara
- Departments of Chemistry and Biological Sciences, University of the Pacific, Stockton, CA 95211, USA; (M.S.); (T.R.); (D.M.); (H.J.); (J.T.)
| | - Danielle MacArt
- Departments of Chemistry and Biological Sciences, University of the Pacific, Stockton, CA 95211, USA; (M.S.); (T.R.); (D.M.); (H.J.); (J.T.)
| | - Caroline Williams
- Institute for Biomedical Science Center for Microbial Pathogenesis, Georgia State University, Decatur, GA 30302, USA;
| | - Ryan Hekman
- Center for Network Systems Biology, Boston University, Boston, MA 02215, USA;
| | - Hyun Joo
- Departments of Chemistry and Biological Sciences, University of the Pacific, Stockton, CA 95211, USA; (M.S.); (T.R.); (D.M.); (H.J.); (J.T.)
| | - Jerry Tsai
- Departments of Chemistry and Biological Sciences, University of the Pacific, Stockton, CA 95211, USA; (M.S.); (T.R.); (D.M.); (H.J.); (J.T.)
| | - Craig Vierra
- Departments of Chemistry and Biological Sciences, University of the Pacific, Stockton, CA 95211, USA; (M.S.); (T.R.); (D.M.); (H.J.); (J.T.)
- Correspondence: ; Tel.: 209-946-3024
| |
Collapse
|
7
|
Poddar H, Breitling R, Takano E. Towards engineering and production of artificial spider silk using tools of synthetic biology. ENGINEERING BIOLOGY 2020; 4:1-6. [PMID: 36970229 PMCID: PMC9996717 DOI: 10.1049/enb.2019.0017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 01/21/2020] [Accepted: 02/10/2020] [Indexed: 12/18/2022] Open
Abstract
Spider silk is one of the strongest biomaterials available in nature. Its mechanical properties make it a good candidate for applications in various fields ranging from protective armour to bandages for wound dressing to coatings for medical implants. Spider silk is formed by an intricate arrangement of spidroins, which are extremely large proteins containing long stretches of repeating segments rich in alanine and glycine. A large amount of research has been directed towards harnessing the spectacular potential of spider silks and using them for different applications. The interdisciplinary approach of synthetic biology is an ideal tool to study these spider silk proteins and work towards the engineering and production of synthetic spider silk. This review aims to highlight the recent progress that has been made in the study of spider silk proteins using different branches of synthetic biology. Here, the authors discuss the different computational approaches, directed evolution techniques and various expression platforms that have been tested for the successful production of spider silk. Future challenges facing the field and possible solutions offered by synthetic biology are also discussed.
Collapse
Affiliation(s)
- Hashwardhan Poddar
- Faculty of Science and Engineering, Manchester Institute of Biotechnology, Manchester Synthetic Biology Research Centre SYNBIOCHEM The University of Manchester Manchester M1 7DN UK
| | - Rainer Breitling
- Faculty of Science and Engineering, Manchester Institute of Biotechnology, Manchester Synthetic Biology Research Centre SYNBIOCHEM The University of Manchester Manchester M1 7DN UK
| | - Eriko Takano
- Faculty of Science and Engineering, Manchester Institute of Biotechnology, Manchester Synthetic Biology Research Centre SYNBIOCHEM The University of Manchester Manchester M1 7DN UK
| |
Collapse
|
8
|
Whaite AD, Wang T, Macdonald J, Cummins SF. Major ampullate silk gland transcriptomes and fibre proteomes of the golden orb-weavers, Nephila plumipes and Nephila pilipes (Araneae: Nephilidae). PLoS One 2018; 13:e0204243. [PMID: 30332416 PMCID: PMC6192577 DOI: 10.1371/journal.pone.0204243] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 09/04/2018] [Indexed: 11/18/2022] Open
Abstract
Natural spider silk is one of the world’s toughest proteinaceous materials, yet a truly biomimetic spider silk is elusive even after several decades of intense focus. In this study, Next-Generation Sequencing was utilised to produce transcriptomes of the major ampullate gland of two Australian golden orb-weavers, Nephila plumipes and Nephila pilipes, in order to identify highly expressed predicted proteins that may co-factor in the construction of the final polymer. Furthermore, proteomics was performed by liquid chromatography tandem-mass spectroscopy to analyse the natural solid silk fibre of each species to confirm highly expressed predicted proteins within the silk gland are present in the final silk product. We assembled the silk gland transcriptomes of N. plumipes and N. pilipes into 69,812 and 70,123 contigs, respectively. Gene expression analysis revealed that silk gene sequences were among the most highly expressed and we were able to procure silk sequences from both species in excess of 1,300 amino acids. However, some of the genes with the highest expression values were not able to be identified from our proteomic analysis. Proteome analysis of “reeled” silk fibres of N. plumipes and N. pilipes revealed 29 and 18 proteins, respectively, most of which were identified as silk fibre proteins. This study is the first silk gland specific transcriptome and proteome analysis for these species and will assist in the future development of a biomimetic spider silk.
Collapse
Affiliation(s)
- Alessandra D Whaite
- GeneCology Research Centre and School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Tianfang Wang
- GeneCology Research Centre and School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Joanne Macdonald
- GeneCology Research Centre and School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia.,Division of Experimental Therapeutics, Columbia University, New York City, New York, United States of America
| | - Scott F Cummins
- GeneCology Research Centre and School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| |
Collapse
|
9
|
Blamires SJ, Nobbs M, Martens PJ, Tso IM, Chuang WT, Chang CK, Sheu HS. Multiscale mechanisms of nutritionally induced property variation in spider silks. PLoS One 2018; 13:e0192005. [PMID: 29390013 PMCID: PMC5794138 DOI: 10.1371/journal.pone.0192005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 01/14/2018] [Indexed: 12/14/2022] Open
Abstract
Variability in spider major ampullate (MA) silk properties at different scales has proven difficult to determine and remains an obstacle to the development of synthetic fibers mimicking MA silk performance. A multitude of techniques may be used to measure multiscale aspects of silk properties. Here we fed five species of Araneoid spider solutions that either contained protein or were protein deprived and performed silk tensile tests, small and wide-angle X-ray scattering (SAXS/WAXS), amino acid composition analyses, and silk gene expression analyses, to resolve persistent questions about how nutrient deprivation induces variations in MA silk mechanical properties across scales. Our analyses found that the properties of each spider's silk varied differently in response to variations in their protein intake. We found changes in the crystalline and non-crystalline nanostructures to play specific roles in inducing the property variations we found. Across treatment MaSp expression patterns differed in each of the five species. We found that in most species MaSp expression and amino acid composition variations did not conform with our predictions based on a traditional MaSp expression model. In general, changes to the silk's alanine and proline compositions influenced the alignment of the proteins within the silk's amorphous region, which influenced silk extensibility and toughness. Variations in structural alignment in the crystalline and non-crystalline regions influenced ultimate strength independent of genetic expression. Our study provides the deepest insights thus far into the mechanisms of how MA silk properties vary from gene expression to nanostructure formations to fiber mechanics. Such knowledge is imperative for promoting the production of synthetic silk fibers.
Collapse
Affiliation(s)
- Sean J. Blamires
- Evolution & Ecology Research Centre, School of Biological, Earth & Environmental Sciences D26, The University of New South Wales, Sydney, Australia
| | - Madeleine Nobbs
- Evolution & Ecology Research Centre, School of Biological, Earth & Environmental Sciences D26, The University of New South Wales, Sydney, Australia
| | - Penny J. Martens
- Graduate School of Biomedical Engineering, Samuels Building F25, The University of New South Wales, Sydney, Australia
| | - I-Min Tso
- Department of Life Science, Tunghai University, Taichung, Taiwan
| | | | - Chung-Kai Chang
- National Synchrotron Radiation Research Centre, Hsinchu, Taiwan
| | - Hwo-Shuenn Sheu
- National Synchrotron Radiation Research Centre, Hsinchu, Taiwan
| |
Collapse
|
10
|
Evolutionary shifts in gene expression decoupled from gene duplication across functionally distinct spider silk glands. Sci Rep 2017; 7:8393. [PMID: 28827773 PMCID: PMC5566633 DOI: 10.1038/s41598-017-07388-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 06/28/2017] [Indexed: 11/08/2022] Open
Abstract
Spider silk synthesis is an emerging model for the evolution of tissue-specific gene expression and the role of gene duplication in functional novelty, but its potential has not been fully realized. Accordingly, we quantified transcript (mRNA) abundance in seven silk gland types and three non-silk gland tissues for three cobweb-weaving spider species. Evolutionary analyses based on expression levels of thousands of homologous transcripts and phylogenetic reconstruction of 605 gene families demonstrated conservation of expression for each gland type among species. Despite serial homology of all silk glands, the expression profiles of the glue-forming aggregate glands were divergent from fiber-forming glands. Also surprising was our finding that shifts in gene expression among silk gland types were not necessarily coupled with gene duplication, even though silk-specific genes belong to multi-paralog gene families. Our results challenge widely accepted models of tissue specialization and significantly advance efforts to replicate silk-based high-performance biomaterials.
Collapse
|
11
|
The Nephila clavipes genome highlights the diversity of spider silk genes and their complex expression. Nat Genet 2017; 49:895-903. [PMID: 28459453 DOI: 10.1038/ng.3852] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 03/29/2017] [Indexed: 12/11/2022]
Abstract
Spider silks are the toughest known biological materials, yet are lightweight and virtually invisible to the human immune system, and they thus have revolutionary potential for medicine and industry. Spider silks are largely composed of spidroins, a unique family of structural proteins. To investigate spidroin genes systematically, we constructed the first genome of an orb-weaving spider: the golden orb-weaver (Nephila clavipes), which builds large webs using an extensive repertoire of silks with diverse physical properties. We cataloged 28 Nephila spidroins, representing all known orb-weaver spidroin types, and identified 394 repeated coding motif variants and higher-order repetitive cassette structures unique to specific spidroins. Characterization of spidroin expression in distinct silk gland types indicates that glands can express multiple spidroin types. We find evidence of an alternatively spliced spidroin, a spidroin expressed only in venom glands, evolutionary mechanisms for spidroin diversification, and non-spidroin genes with expression patterns that suggest roles in silk production.
Collapse
|
12
|
Correa-Garhwal SM, Chaw RC, Clarke TH, Ayoub NA, Hayashi CY. Silk gene expression of theridiid spiders: implications for male-specific silk use. ZOOLOGY 2017; 122:107-114. [PMID: 28536006 DOI: 10.1016/j.zool.2017.04.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 04/21/2017] [Accepted: 04/21/2017] [Indexed: 01/15/2023]
Abstract
Spiders (order Araneae) rely on their silks for essential tasks, such as dispersal, prey capture, and reproduction. Spider silks are largely composed of spidroins, members of a protein family that are synthesized in silk glands. As needed, silk stored in silk glands is extruded through spigots on the spinnerets. Nearly all studies of spider silks have been conducted on females; thus, little is known about male silk biology. To shed light on silk use by males, we compared silk gene expression profiles of mature males to those of females from three cob-web weaving species (Theridiidae). We de novo assembled species-specific male transcriptomes from Latrodectus hesperus, Latrodectus geometricus, and Steatoda grossa followed by differential gene expression analyses. Consistent with their complement of silk spigots, male theridiid spiders express appreciable amounts of aciniform, major ampullate, minor ampullate, and pyriform spidroin genes but not tubuliform spidroin genes. The relative expression levels of particular spidroin genes varied between sexes and species. Because mature males desert their prey-capture webs and become cursorial in their search for mates, we anticipated that major ampullate (dragline) spidroin genes would be the silk genes most highly expressed by males. Indeed, major ampullate spidroin genes had the highest expression in S. grossa males. However, minor ampullate spidroin genes were the most highly expressed spidroin genes in L. geometricus and L. hesperus males. Our expression profiling results suggest species-specific adaptive divergence of silk use by male theridiids.
Collapse
Affiliation(s)
| | - R Crystal Chaw
- Department of Biology, University of California, Riverside, CA 92521, USA.
| | - Thomas H Clarke
- Department of Biology, University of California, Riverside, CA 92521, USA; Department of Biology, Washington and Lee University, Lexington, VA 24450, USA; J. Craig Venter Institute, Rockville, MD 20850, USA.
| | - Nadia A Ayoub
- Department of Biology, Washington and Lee University, Lexington, VA 24450, USA.
| | - Cheryl Y Hayashi
- Department of Biology, University of California, Riverside, CA 92521, USA; Division of Invertebrate Zoology, American Museum of Natural History, New York, NY 10024, USA.
| |
Collapse
|
13
|
Vienneau-Hathaway JM, Brassfield ER, Lane AK, Collin MA, Correa-Garhwal SM, Clarke TH, Schwager EE, Garb JE, Hayashi CY, Ayoub NA. Duplication and concerted evolution of MiSp-encoding genes underlie the material properties of minor ampullate silks of cobweb weaving spiders. BMC Evol Biol 2017; 17:78. [PMID: 28288560 PMCID: PMC5348893 DOI: 10.1186/s12862-017-0927-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 02/24/2017] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Orb-web weaving spiders and their relatives use multiple types of task-specific silks. The majority of spider silk studies have focused on the ultra-tough dragline silk synthesized in major ampullate glands, but other silk types have impressive material properties. For instance, minor ampullate silks of orb-web weaving spiders are as tough as draglines, due to their higher extensibility despite lower strength. Differences in material properties between silk types result from differences in their component proteins, particularly members of the spidroin (spider fibroin) gene family. However, the extent to which variation in material properties within a single silk type can be explained by variation in spidroin sequences is unknown. Here, we compare the minor ampullate spidroins (MiSp) of orb-weavers and cobweb weavers. Orb-web weavers use minor ampullate silk to form the auxiliary spiral of the orb-web while cobweb weavers use it to wrap prey, suggesting that selection pressures on minor ampullate spidroins (MiSp) may differ between the two groups. RESULTS We report complete or nearly complete MiSp sequences from five cobweb weaving spider species and measure material properties of minor ampullate silks in a subset of these species. We also compare MiSp sequences and silk properties of our cobweb weavers to published data for orb-web weavers. We demonstrate that all our cobweb weavers possess multiple MiSp loci and that one locus is more highly expressed in at least two species. We also find that the proportion of β-spiral-forming amino acid motifs in MiSp positively correlates with minor ampullate silk extensibility across orb-web and cobweb weavers. CONCLUSIONS MiSp sequences vary dramatically within and among spider species, and have likely been subject to multiple rounds of gene duplication and concerted evolution, which have contributed to the diverse material properties of minor ampullate silks. Our sequences also provide templates for recombinant silk proteins with tailored properties.
Collapse
Affiliation(s)
| | | | - Amanda Kelly Lane
- Department of Biology, Washington and Lee University, Lexington, VA USA
| | | | | | - Thomas H. Clarke
- Department of Biology, Washington and Lee University, Lexington, VA USA
- Department of Biology, University of California, Riverside, CA USA
| | - Evelyn E. Schwager
- Department of Biological Sciences, University of Massachusetts, Lowell, MA USA
| | - Jessica E. Garb
- Department of Biological Sciences, University of Massachusetts, Lowell, MA USA
| | | | - Nadia A. Ayoub
- Department of Biology, Washington and Lee University, Lexington, VA USA
| |
Collapse
|
14
|
Chaw RC, Arensburger P, Clarke TH, Ayoub NA, Hayashi CY. Candidate egg case silk genes for the spider Argiope argentata from differential gene expression analyses. INSECT MOLECULAR BIOLOGY 2016; 25:757-768. [PMID: 27500384 DOI: 10.1111/imb.12260] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Orb-web weaving spiders produce a variety of task-specific silks from specialized silk glands. The genetics underlying the synthesis of specific silk types are largely unknown, and transcriptome analysis could be a powerful approach for identifying candidate genes. However, de novo assembly and expression profiling of silk glands with RNA-sequencing (RNAseq) are problematic because the few known gene transcripts for silk proteins are extremely long and highly repetitive. To identify candidate genes for tubuliform (egg case) silk synthesis by the orb-weaver Argiope argentata (Araneidae), we estimated transcript abundance using two sequencing methods: RNAseq reads from throughout the length of mRNA molecules, and 3' digital gene expression reads from the 3' region of mRNA molecules. Both analyses identified similar sets of genes as differentially expressed when comparing tubuliform and nonsilk gland tissue. However, incompletely assembled silk gene transcripts were identified as differentially expressed because of RNAseq read alignments to highly repetitive regions, confounding interpretation of RNAseq results. Homologues of egg case silk protein (ECP) genes were upregulated in tubuliform glands. This discovery is the first description of ECP homologues in an araneid. We also propose additional candidate genes involved in synthesis of tubuliform or other silk types.
Collapse
Affiliation(s)
- R C Chaw
- Department of Biology, University of California, Riverside, CA, USA
| | - P Arensburger
- Department of Biological Sciences, California State Polytechnic University, Pomona, CA, USA
| | - T H Clarke
- Department of Biology, University of California, Riverside, CA, USA
- Department of Biology, Washington and Lee University, Lexington, VA, USA
| | - N A Ayoub
- Department of Biology, Washington and Lee University, Lexington, VA, USA
| | - C Y Hayashi
- Department of Biology, University of California, Riverside, CA, USA
| |
Collapse
|
15
|
Comprehensive Proteomic Analysis of Spider Dragline Silk from Black Widows: A Recipe to Build Synthetic Silk Fibers. Int J Mol Sci 2016; 17:ijms17091537. [PMID: 27649139 PMCID: PMC5037812 DOI: 10.3390/ijms17091537] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 09/07/2016] [Accepted: 09/07/2016] [Indexed: 12/15/2022] Open
Abstract
The outstanding material properties of spider dragline silk fibers have been attributed to two spidroins, major ampullate spidroins 1 and 2 (MaSp1 and MaSp2). Although dragline silk fibers have been treated with different chemical solvents to elucidate the relationship between protein structure and fiber mechanics, there has not been a comprehensive proteomic analysis of the major ampullate (MA) gland, its spinning dope, and dragline silk using a wide range of chaotropic agents, inorganic salts, and fluorinated alcohols to elucidate their complete molecular constituents. In these studies, we perform in-solution tryptic digestions of solubilized MA glands, spinning dope and dragline silk fibers using five different solvents, followed by nano liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis with an Orbitrap Fusion™ Tribrid™. To improve protein identification, we employed three different tryptic peptide fragmentation modes, which included collision-induced dissociation (CID), electron transfer dissociation (ETD), and high energy collision dissociation (HCD) to discover proteins involved in the silk assembly pathway and silk fiber. In addition to MaSp1 and MaSp2, we confirmed the presence of a third spidroin, aciniform spidroin 1 (AcSp1), widely recognized as the major constituent of wrapping silk, as a product of dragline silk. Our findings also reveal that MA glands, spinning dope, and dragline silk contain at least seven common proteins: three members of the Cysteine-Rich Protein Family (CRP1, CRP2 and CRP4), cysteine-rich secretory protein 3 (CRISP3), fasciclin and two uncharacterized proteins. In summary, this study provides a proteomic blueprint to construct synthetic silk fibers that most closely mimic natural fibers.
Collapse
|
16
|
Chaw RC, Correa-Garhwal SM, Clarke TH, Ayoub NA, Hayashi CY. Proteomic Evidence for Components of Spider Silk Synthesis from Black Widow Silk Glands and Fibers. J Proteome Res 2015; 14:4223-31. [PMID: 26302244 PMCID: PMC5075943 DOI: 10.1021/acs.jproteome.5b00353] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Spider
silk research has largely focused on spidroins, proteins
that are the primary components of spider silk fibers. Although a
number of spidroins have been characterized, other types of proteins
associated with silk synthesis are virtually unknown. Previous analyses
of tissue-specific RNA-seq libraries identified 647 predicted genes
that were differentially expressed in silk glands of the Western black
widow, Latrodectus hesperus. Only ∼5%
of these silk-gland specific transcripts (SSTs) encode spidroins;
although the remaining predicted genes presumably encode other proteins
associated with silk production, this is mostly unverified. Here,
we used proteomic analysis of multiple silk glands and dragline silk
fiber to investigate the translation of the differentially expressed
genes. We find 48 proteins encoded by the differentially expressed
transcripts in L. hesperus major ampullate,
minor ampullate, and tubuliform silk glands and detect 17 SST encoded
proteins in major ampullate silk fibers. The observed proteins include
known silk-related proteins, but most are uncharacterized, with no
annotation. These unannotated proteins likely include novel silk-associated
proteins. Major and minor ampullate glands have the highest overlap
of identified proteins, consistent with their shared, distinctive
ampullate shape and the overlapping functions of major and minor ampullate
silks. Our study substantiates and prioritizes predictions from differential
expression analysis of spider silk gland transcriptomes.
Collapse
Affiliation(s)
- Ro Crystal Chaw
- Department of Biology, University of California , Riverside, California 92521, United States
| | - Sandra M Correa-Garhwal
- Department of Biology, University of California , Riverside, California 92521, United States
| | - Thomas H Clarke
- Department of Biology, Washington and Lee University , Lexington, Virginia 24450, United States
| | - Nadia A Ayoub
- Department of Biology, Washington and Lee University , Lexington, Virginia 24450, United States
| | - Cheryl Y Hayashi
- Department of Biology, University of California , Riverside, California 92521, United States
| |
Collapse
|
17
|
Clarke TH, Garb JE, Hayashi CY, Arensburger P, Ayoub NA. Spider Transcriptomes Identify Ancient Large-Scale Gene Duplication Event Potentially Important in Silk Gland Evolution. Genome Biol Evol 2015; 7:1856-70. [PMID: 26058392 PMCID: PMC4524477 DOI: 10.1093/gbe/evv110] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The evolution of specialized tissues with novel functions, such as the silk synthesizing glands in spiders, is likely an influential driver of adaptive success. Large-scale gene duplication events and subsequent paralog divergence are thought to be required for generating evolutionary novelty. Such an event has been proposed for spiders, but not tested. We de novo assembled transcriptomes from three cobweb weaving spider species. Based on phylogenetic analyses of gene families with representatives from each of the three species, we found numerous duplication events indicative of a whole genome or segmental duplication. We estimated the age of the gene duplications relative to several speciation events within spiders and arachnids and found that the duplications likely occurred after the divergence of scorpions (order Scorpionida) and spiders (order Araneae), but before the divergence of the spider suborders Mygalomorphae and Araneomorphae, near the evolutionary origin of spider silk glands. Transcripts that are expressed exclusively or primarily within black widow silk glands are more likely to have a paralog descended from the ancient duplication event and have elevated amino acid replacement rates compared with other transcripts. Thus, an ancient large-scale gene duplication event within the spider lineage was likely an important source of molecular novelty during the evolution of silk gland-specific expression. This duplication event may have provided genetic material for subsequent silk gland diversification in the true spiders (Araneomorphae).
Collapse
Affiliation(s)
| | - Jessica E Garb
- Department of Biological Sciences, University of Massachusetts, Lowell
| | | | - Peter Arensburger
- Department of Biological Sciences, California State Polytechnic University, Pomona
| | | |
Collapse
|
18
|
Rising A, Johansson J. Toward spinning artificial spider silk. Nat Chem Biol 2015; 11:309-15. [DOI: 10.1038/nchembio.1789] [Citation(s) in RCA: 225] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 03/02/2015] [Indexed: 12/25/2022]
|
19
|
Pham T, Chuang T, Lin A, Joo H, Tsai J, Crawford T, Zhao L, Williams C, Hsia Y, Vierra C. Dragline silk: a fiber assembled with low-molecular-weight cysteine-rich proteins. Biomacromolecules 2014; 15:4073-81. [PMID: 25259849 DOI: 10.1021/bm5011239] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dragline silk has been proposed to contain two main protein constituents, MaSp1 and MaSp2. However, the mechanical properties of synthetic spider silks spun from recombinant MaSp1 and MaSp2 proteins have yet to approach natural fibers, implying the natural spinning dope is missing critical factors. Here we report the discovery of novel molecular constituents within the spinning dope that are extruded into dragline silk. Protein studies of the liquid spinning dope from the major ampullate gland, coupled with the analysis of dragline silk fibers using mass spectrometry, demonstrate the presence of a new family of low-molecular-weight cysteine-rich proteins (CRPs) that colocalize with the MA fibroins. Expression of the CRP family members is linked to dragline silk production, specifically MaSp1 and MaSp2 mRNA synthesis. Biochemical data support that CRP molecules are secreted into the spinning dope and assembled into macromolecular complexes via disulfide bond linkages. Sequence analysis supports that CRP molecules share similarities to members that belong to the cystine slipknot superfamily, suggesting that these factors may have evolved to increase fiber toughness by serving as molecular hubs that dissipate large amounts of energy under stress. Collectively, our findings provide molecular details about the components of dragline silk, providing new insight that will advance materials development of synthetic spider silk for industrial applications.
Collapse
Affiliation(s)
- Thanh Pham
- Departments of †Biology and §Chemistry, University of the Pacific , Stockton, California 95211, United States
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Sanggaard KW, Bechsgaard JS, Fang X, Duan J, Dyrlund TF, Gupta V, Jiang X, Cheng L, Fan D, Feng Y, Han L, Huang Z, Wu Z, Liao L, Settepani V, Thøgersen IB, Vanthournout B, Wang T, Zhu Y, Funch P, Enghild JJ, Schauser L, Andersen SU, Villesen P, Schierup MH, Bilde T, Wang J. Spider genomes provide insight into composition and evolution of venom and silk. Nat Commun 2014; 5:3765. [PMID: 24801114 PMCID: PMC4273655 DOI: 10.1038/ncomms4765] [Citation(s) in RCA: 187] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 03/31/2014] [Indexed: 12/24/2022] Open
Abstract
Spiders are ecologically important predators with complex venom and extraordinarily tough
silk that enables capture of large prey. Here we present the assembled genome of the social
velvet spider and a draft assembly of the tarantula genome that represent two major
taxonomic groups of spiders. The spider genomes are large with short exons and long introns,
reminiscent of mammalian genomes. Phylogenetic analyses place spiders and ticks as sister
groups supporting polyphyly of the Acari. Complex sets of venom and silk genes/proteins are
identified. We find that venom genes evolved by sequential duplication, and that the toxic
effect of venom is most likely activated by proteases present in the venom. The set of silk
genes reveals a highly dynamic gene evolution, new types of silk genes and proteins, and a
novel use of aciniform silk. These insights create new opportunities for pharmacological
applications of venom and biomaterial applications of silk. Spiders use self-produced venom and silk for their daily survival. Here, the
authors report the assembled genome of the social velvet spider and a draft assembly of the
tarantula genome and, together with proteomic data, provide insights into the evolution of
genes that affect venom and silk production.
Collapse
Affiliation(s)
- Kristian W Sanggaard
- 1] Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark [2] Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark [3]
| | | | - Xiaodong Fang
- 1] BGI-Tech, BGI-Shenzhen, Shenzhen 518083, China [2] Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark [3]
| | - Jinjie Duan
- Bioinformatics Research Center (BiRC), Aarhus University, 8000 Aarhus C, Denmark
| | - Thomas F Dyrlund
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Vikas Gupta
- 1] Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark [2] Bioinformatics Research Center (BiRC), Aarhus University, 8000 Aarhus C, Denmark
| | | | - Ling Cheng
- BGI-Tech, BGI-Shenzhen, Shenzhen 518083, China
| | | | - Yue Feng
- BGI-Tech, BGI-Shenzhen, Shenzhen 518083, China
| | - Lijuan Han
- BGI-Tech, BGI-Shenzhen, Shenzhen 518083, China
| | | | - Zongze Wu
- BGI-Tech, BGI-Shenzhen, Shenzhen 518083, China
| | - Li Liao
- BGI-Tech, BGI-Shenzhen, Shenzhen 518083, China
| | | | - Ida B Thøgersen
- 1] Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark [2] Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | | | - Tobias Wang
- Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| | - Yabing Zhu
- BGI-Tech, BGI-Shenzhen, Shenzhen 518083, China
| | - Peter Funch
- Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| | - Jan J Enghild
- 1] Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark [2] Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | | | - Stig U Andersen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Palle Villesen
- 1] Bioinformatics Research Center (BiRC), Aarhus University, 8000 Aarhus C, Denmark [2] Department of Clinical Medicine, Aarhus University, 8000 Aarhus C, Denmark
| | - Mikkel H Schierup
- 1] Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark [2] Bioinformatics Research Center (BiRC), Aarhus University, 8000 Aarhus C, Denmark
| | - Trine Bilde
- Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| | - Jun Wang
- 1] BGI-Tech, BGI-Shenzhen, Shenzhen 518083, China [2] Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark [3] King Abdulaziz University, Jeddah 21441, Saudi Arabia
| |
Collapse
|