1
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Ontogenetic dynamics of the subepidermal spicule complex in Nudibranchia (Gastropoda): the case of Onchidoris muricata. ZOOLOGY 2021; 144:125886. [PMID: 33450621 DOI: 10.1016/j.zool.2020.125886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 11/18/2020] [Accepted: 11/23/2020] [Indexed: 11/21/2022]
Abstract
Spicules are mineral-based biocomposites skeletal structures that are widely distributed among phylogenetically distant groups of invertebrates (Porifera, Cnidaria, Mollusca, Echinodermata). Subepidermal spicules are formed under the ectodermal epithelium and are characterized for all groups except mollusks (Aplacophora, Polyplacophora, Bivalvia), their spicules are located on the surface of the body. However, one group of mollusks (Gastropoda: Heterobranchia) have unique subepidermal spicules that have never been detected above the ectodermal epithelium and similarly to those characterized for Porifera, Cnidaria and Echinodermata. Understanding subepidermal spicule formation in mollusks could help solve the question on the origin of spicules. Spicules in nudibranchs have been described for more than 150 years, yet ontogenetic dynamics of spicules have never been studied and the full mechanism of their formation remains unknown. Herein we investigate the spicule formation in different stages of postlarval development of the nudibranch Onchidoris muricata (O.F. Müller, 1776). For the first time, ontogenetic transformations of the spicule complex are described using experiments and different morphological methods. Our studies demonstrate that spicules of O. muricata form in the subepidermal space in early developmental stages immediately after veliger settlement. A single spicule forms inside a huge vacuole within a sclerocyte and remains there throughout the entire life of the specimen. Signs of spicule or sclerocyte migration under the epithelium in postlarval development was not found. Spicules only form during larval settlement, increasing only in size as development furthers. For the first time, spicule mineralization zones were detected at the tips of the spicules as well as the presence of collagen I in the overall composition of the spicules. Thus, our findings suggest that spicules form by an ectodermal cell that emerged under the ectodermal epithelium during the earliest stages of postlarval development.
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2
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Penney B, Sigwart J, Parkinson D. Spicules and skeletons: mantle musculature of two species of dorid nudibranchs (Gastropoda: Nudibranchia: Doridina). CAN J ZOOL 2020; 98:777-786. [DOI: 10.1139/cjz-2019-0295] [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
Molluscs often possess complex calcified elements in addition to the shell, but how these elements function and relate to other tissues is often poorly understood. Dorid nudibranchs typically possess innumerable calcareous spicules arranged in complex networks. To describe how these spicules interact with muscles and connective tissue, we reconstructed tomographic digital models using serial sections and synchrotron micro-computed tomography. In two species with dramatically different spicule network morphologies, musculature was divided into a dorsal layer of crossed fibres, a ventral layer of branching radial fibres, and scattered dorsoventral fibres in between. These two species differed in the size of their dorsal tubercles, which was reflected in the organization of dorsal musculature, and in the amount and organization of connective tissue. In Platydoris sanguinea Bergh, 1905, dense mats of spicules sandwiched a layer of connective tissue with fewer spicules and muscle insertions only onto the ventral spicules. In Cadlina luteomarginata MacFarland, 1966, thick tracts of spicules are surrounded by a sheath of connective tissue. Muscles surround and insert into the dorsal tubercle spicule layer. Thus, both species appear to use the spicule network for muscle antagonism and transfer of motion, but the different arrangement of elements suggests that they use this skeleton in quite different ways.
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Affiliation(s)
- B.K. Penney
- Department of Biology, Saint Anselm College, Box 1742, Manchester, NH 03102, USA
| | - J.D. Sigwart
- Queen’s University Belfast, Marine Laboratory, Portaferry BT22 1PF, County Down, Northern Ireland
- Senckenberg Research Institute, 25 Senckenberganlage, Frankfurt 60325, Germany
| | - D.Y. Parkinson
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Mail Stop 15-317, Berkeley, CA 94720, USA
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3
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Yang Z, Zhang L, Hu J, Wang J, Bao Z, Wang S. The evo-devo of molluscs: Insights from a genomic perspective. Evol Dev 2020; 22:409-424. [PMID: 32291964 DOI: 10.1111/ede.12336] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Molluscs represent one of ancient and evolutionarily most successful groups of marine invertebrates, with a tremendous diversity of morphology, behavior, and lifestyle. Molluscs are excellent subjects for evo-devo studies; however, understanding of the evo-devo of molluscs has been largely hampered by incomplete fossil records and limited molecular data. Recent advancement of genomics and other technologies has greatly fueled the molluscan "evo-devo" field, and decoding of several molluscan genomes provides unprecedented insights into molluscan biology and evolution. Here, we review the recent progress of molluscan genome sequencing as well as novel insights gained from their genomes, by emphasizing how molluscan genomics enhances our understanding of the evo-devo of molluscs.
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Affiliation(s)
- Zhihui Yang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Lingling Zhang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Jingjie Hu
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Jing Wang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Zhenmin Bao
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Fisheries Science and Food Production Processes, Pilot Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Shi Wang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,The Sars-Fang Centre, Ocean University of China, Qingdao, China
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4
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Sun J, Chen C, Miyamoto N, Li R, Sigwart JD, Xu T, Sun Y, Wong WC, Ip JCH, Zhang W, Lan Y, Bissessur D, Watsuji TO, Watanabe HK, Takaki Y, Ikeo K, Fujii N, Yoshitake K, Qiu JW, Takai K, Qian PY. The Scaly-foot Snail genome and implications for the origins of biomineralised armour. Nat Commun 2020; 11:1657. [PMID: 32269225 PMCID: PMC7142155 DOI: 10.1038/s41467-020-15522-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 03/13/2020] [Indexed: 12/22/2022] Open
Abstract
The Scaly-foot Snail, Chrysomallon squamiferum, presents a combination of biomineralised features, reminiscent of enigmatic early fossil taxa with complex shells and sclerites such as sachtids, but in a recently-diverged living species which even has iron-infused hard parts. Thus the Scaly-foot Snail is an ideal model to study the genomic mechanisms underlying the evolutionary diversification of biomineralised armour. Here, we present a high-quality whole-genome assembly and tissue-specific transcriptomic data, and show that scale and shell formation in the Scaly-foot Snail employ independent subsets of 25 highly-expressed transcription factors. Comparisons with other lophotrochozoan genomes imply that this biomineralisation toolkit is ancient, though expression patterns differ across major lineages. We suggest that the ability of lophotrochozoan lineages to generate a wide range of hard parts, exemplified by the remarkable morphological disparity in Mollusca, draws on a capacity for dynamic modification of the expression and positioning of toolkit elements across the genome.
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Affiliation(s)
- Jin Sun
- Department of Ocean Science, Division of Life Science and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guanzhou), The Hong Kong University of Science and Technology, Hong Kong, China
| | - Chong Chen
- X-STAR, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa, 237-0061, Japan
| | - Norio Miyamoto
- X-STAR, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa, 237-0061, Japan
| | - Runsheng Li
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Julia D Sigwart
- Marine Laboratory, Queen's University Belfast, Portaferry, N. Ireland
- Senckenberg Museum, Frankfurt, Germany
| | - Ting Xu
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Yanan Sun
- Department of Ocean Science, Division of Life Science and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guanzhou), The Hong Kong University of Science and Technology, Hong Kong, China
| | - Wai Chuen Wong
- Department of Ocean Science, Division of Life Science and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guanzhou), The Hong Kong University of Science and Technology, Hong Kong, China
| | - Jack C H Ip
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Weipeng Zhang
- Department of Ocean Science, Division of Life Science and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guanzhou), The Hong Kong University of Science and Technology, Hong Kong, China
| | - Yi Lan
- Department of Ocean Science, Division of Life Science and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guanzhou), The Hong Kong University of Science and Technology, Hong Kong, China
| | - Dass Bissessur
- Department for Continental Shelf, Maritime Zones Administration & Exploration, Ministry of Defence and Rodrigues, 2nd Floor, Belmont House, 12 Intendance Street, Port-Louis, 11328, Mauritius
| | - Tomo-O Watsuji
- X-STAR, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa, 237-0061, Japan
- Department of Food and Nutrition, Higashi-Chikushi Junior College, Kitakyusyu, Japan
| | - Hiromi Kayama Watanabe
- X-STAR, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa, 237-0061, Japan
| | - Yoshihiro Takaki
- X-STAR, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa, 237-0061, Japan
| | - Kazuho Ikeo
- National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, Japan
| | - Nobuyuki Fujii
- National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, Japan
| | - Kazutoshi Yoshitake
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Jian-Wen Qiu
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Ken Takai
- X-STAR, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa, 237-0061, Japan.
| | - Pei-Yuan Qian
- Department of Ocean Science, Division of Life Science and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guanzhou), The Hong Kong University of Science and Technology, Hong Kong, China.
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5
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Wang J, Zhang L, Lian S, Qin Z, Zhu X, Dai X, Huang Z, Ke C, Zhou Z, Wei J, Liu P, Hu N, Zeng Q, Dong B, Dong Y, Kong D, Zhang Z, Liu S, Xia Y, Li Y, Zhao L, Xing Q, Huang X, Hu X, Bao Z, Wang S. Evolutionary transcriptomics of metazoan biphasic life cycle supports a single intercalation origin of metazoan larvae. Nat Ecol Evol 2020; 4:725-736. [PMID: 32203475 DOI: 10.1038/s41559-020-1138-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 02/06/2020] [Indexed: 12/16/2022]
Abstract
The transient larva-bearing biphasic life cycle is the hallmark of many metazoan phyla, but how metazoan larvae originated remains a major enigma in animal evolution. There are two hypotheses for larval origin. The 'larva-first' hypothesis suggests that the first metazoans were similar to extant larvae, with later evolution of the adult-added biphasic life cycle; the 'adult-first' hypothesis suggests that the first metazoans were adult forms, with the biphasic life cycle arising later via larval intercalation. Here, we investigate the evolutionary origin of primary larvae by conducting ontogenetic transcriptome profiling for Mollusca-the largest marine phylum characterized by a trochophore larval stage and highly variable adult forms. We reveal that trochophore larvae exhibit rapid transcriptome evolution with extraordinary incorporation of novel genes (potentially contributing to adult shell evolution), and that cell signalling/communication genes (for example, caveolin and innexin) are probably crucial for larval evolution. Transcriptome age analysis of eight metazoan species reveals the wide presence of young larval transcriptomes in both trochozoans and other major metazoan lineages, therefore arguing against the prevailing larva-first hypothesis. Our findings support an adult-first evolutionary scenario with a single metazoan larval intercalation, and suggest that the first appearance of proto-larva probably occurred after the divergence of direct-developing Ctenophora from a metazoan ancestor.
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Affiliation(s)
- Jing Wang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Lingling Zhang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Shanshan Lian
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Zhenkui Qin
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Xuan Zhu
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Xiaoting Dai
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Zekun Huang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Caihuan Ke
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Zunchun Zhou
- Liaoning Key Lab of Marine Fishery Molecular Biology, Liaoning Ocean and Fisheries Science Research Institute, Dalian, China
| | - Jiankai Wei
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Pingping Liu
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Naina Hu
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Qifan Zeng
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Bo Dong
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Ying Dong
- Liaoning Key Lab of Marine Fishery Molecular Biology, Liaoning Ocean and Fisheries Science Research Institute, Dalian, China
| | - Dexu Kong
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Zhifeng Zhang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Sinuo Liu
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Yu Xia
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Yangping Li
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Liang Zhao
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Qiang Xing
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Xiaoting Huang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Xiaoli Hu
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Fisheries Science and Food Production Processes, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Zhenmin Bao
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Fisheries Science and Food Production Processes, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Shi Wang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China. .,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China. .,The Sars-Fang Centre, Ocean University of China, Qingdao, China.
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6
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Sun J, Mu H, Ip JCH, Li R, Xu T, Accorsi A, Sánchez Alvarado A, Ross E, Lan Y, Sun Y, Castro-Vazquez A, Vega IA, Heras H, Ituarte S, Van Bocxlaer B, Hayes KA, Cowie RH, Zhao Z, Zhang Y, Qian PY, Qiu JW. Signatures of Divergence, Invasiveness, and Terrestrialization Revealed by Four Apple Snail Genomes. Mol Biol Evol 2020; 36:1507-1520. [PMID: 30980073 PMCID: PMC6573481 DOI: 10.1093/molbev/msz084] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The family Ampullariidae includes both aquatic and amphibious apple snails. They are an emerging model for evolutionary studies due to the high diversity, ancient history, and wide geographical distribution. Insight into drivers of ampullariid evolution is hampered, however, by the lack of genomic resources. Here, we report the genomes of four ampullariids spanning the Old World (Lanistes nyassanus) and New World (Pomacea canaliculata, P. maculata, and Marisa cornuarietis) clades. The ampullariid genomes have conserved ancient bilaterial karyotype features and a novel Hox gene cluster rearrangement, making them valuable in comparative genomic studies. They have expanded gene families related to environmental sensing and cellulose digestion, which may have facilitated some ampullarids to become notorious invasive pests. In the amphibious Pomacea, novel acquisition of an egg neurotoxin and a protein for making the calcareous eggshell may have been key adaptations enabling their transition from underwater to terrestrial egg deposition.
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Affiliation(s)
- Jin Sun
- Department of Ocean Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Huawei Mu
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Jack C H Ip
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Runsheng Li
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Ting Xu
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Alice Accorsi
- Howard Hughes Medical Institute, Kansas City, MO.,Stowers Institute for Medical Research, Kansas City, MO
| | - Alejandro Sánchez Alvarado
- Howard Hughes Medical Institute, Kansas City, MO.,Stowers Institute for Medical Research, Kansas City, MO
| | - Eric Ross
- Howard Hughes Medical Institute, Kansas City, MO.,Stowers Institute for Medical Research, Kansas City, MO
| | - Yi Lan
- Department of Ocean Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Yanan Sun
- Department of Ocean Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Alfredo Castro-Vazquez
- Instituto de Histología y Embriología (IHEM-CONICET), Mendoza, Argentina.,Instituto de Fisiología (FCM-UNCuyo), Mendoza, Argentina
| | - Israel A Vega
- Instituto de Histología y Embriología (IHEM-CONICET), Mendoza, Argentina.,Instituto de Fisiología (FCM-UNCuyo), Mendoza, Argentina
| | - Horacio Heras
- Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner", INIBIOLP. CONICET CCT La Plata-Universidad Nacional de La Plata (UNLP), La Plata, Argentina.,Facultad de Ciencias Naturales y Museo, UNLP, La Plata, Argentina
| | - Santiago Ituarte
- Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner", INIBIOLP. CONICET CCT La Plata-Universidad Nacional de La Plata (UNLP), La Plata, Argentina
| | - Bert Van Bocxlaer
- Centre national de la recherche scientifique (CNRS), UMR 8198 Evolution, Ecology, Paleotology, Université de Lille, Lille, France
| | | | - Robert H Cowie
- Pacific Biosciences Research Center, University of Hawaii, Honolulu, HI
| | - Zhongying Zhao
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Yu Zhang
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Pei-Yuan Qian
- Department of Ocean Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Jian-Wen Qiu
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
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7
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Van Bocxlaer B, Ortiz-Sepulveda CM, Gurdebeke PR, Vekemans X. Adaptive divergence in shell morphology in an ongoing gastropod radiation from Lake Malawi. BMC Evol Biol 2020; 20:5. [PMID: 31918659 PMCID: PMC6953155 DOI: 10.1186/s12862-019-1570-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 12/19/2019] [Indexed: 11/21/2022] Open
Abstract
Background Ecological speciation is a prominent mechanism of diversification but in many evolutionary radiations, particularly in invertebrates, it remains unclear whether supposedly critical ecological traits drove or facilitated diversification. As a result, we lack accurate knowledge on the drivers of diversification for most evolutionary radiations along the tree of life. Freshwater mollusks present an enigmatic example: Putatively adaptive radiations are being described in various families, typically from long-lived lakes, whereas other taxa represent celebrated model systems in the study of ecophenotypic plasticity. Here we examine determinants of shell-shape variation in three nominal species of an ongoing ampullariid radiation in the Malawi Basin (Lanistes nyassanus, L. solidus and Lanistes sp. (ovum-like)) with a common garden experiment and semi-landmark morphometrics. Results We found significant differences in survival and fecundity among these species in contrasting habitats. Morphological differences observed in the wild persisted in our experiments for L. nyassanus versus L. solidus and L. sp. (ovum-like), but differences between L. solidus and L. sp. (ovum-like) disappeared and re-emerged in the F1 and F2 generations, respectively. These results indicate that plasticity occurred, but that it is not solely responsible for the observed differences. Our experiments provide the first unambiguous evidence for genetic divergence in shell morphology in an ongoing freshwater gastropod radiation in association with marked fitness differences among species under controlled habitat conditions. Conclusions Our results indicate that differences in shell morphology among Lanistes species occupying different habitats have an adaptive value. These results also facilitate an accurate reinterpretation of morphological variation in fossil Lanistes radiations, and thus macroevolutionary dynamics. Finally, our work testifies that the shells of freshwater gastropods may retain signatures of adaptation at low taxonomic levels, beyond representing an evolutionary novelty responsible for much of the diversity and disparity in mollusks altogether.
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Affiliation(s)
- Bert Van Bocxlaer
- CNRS, Univ. Lille, UMR 8198 - Evo-Eco-Paleo, F-59000, Lille, France. .,Limnology Unit, Department of Biology, Ghent University, 9000, Ghent, Belgium. .,Department of Geology, Ghent University, 9000, Ghent, Belgium.
| | | | | | - Xavier Vekemans
- CNRS, Univ. Lille, UMR 8198 - Evo-Eco-Paleo, F-59000, Lille, France
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8
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Chen C, Watanabe HK, Nagai Y, Toyofuku T, Xu T, Sun J, Qiu JW, Sasaki T. Complex factors shape phenotypic variation in deep-sea limpets. Biol Lett 2019; 15:20190504. [PMID: 31640530 PMCID: PMC6832178 DOI: 10.1098/rsbl.2019.0504] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 09/27/2019] [Indexed: 12/26/2022] Open
Abstract
Pectinodontid limpets are important members of deep-sea hot vents and cold seeps as can be seen by their conspicuous presence in both extant and extinct systems. They have traditionally been classified into different genera and species based on shell and radula characteristics; the reliability of these characters has been questioned but not tested thoroughly. Here, for the first time in taxa endemic to deep-sea chemosynthetic ecosystems, we combine substrate translocation with molecular data to assess the plasticity and variability of key phenotypic characters. Molecular data revealed that several 'species' of extant vent/seep pectinodontids actually represent intergrading morphotypes of a single, highly plastic, evolutionary lineage, with each morphological trait being possibly influenced differently by environmental and genetic factors. Our results challenge previous interpretations of paleoecology at fossil chemosynthetic ecosystems and highlight the importance of modern analogues in understanding fossil systems.
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Affiliation(s)
- Chong Chen
- X-STAR, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan
| | - Hiromi Kayama Watanabe
- X-STAR, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan
| | - Yukiko Nagai
- X-STAR, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan
| | - Takashi Toyofuku
- X-STAR, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan
| | - Ting Xu
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Kowloon, Hong Kong
| | - Jin Sun
- Department of Ocean Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Jian-Wen Qiu
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Kowloon, Hong Kong
| | - Takenori Sasaki
- The University Museum, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Rudraraju S, Moulton DE, Chirat R, Goriely A, Garikipati K. A computational framework for the morpho-elastic development of molluskan shells by surface and volume growth. PLoS Comput Biol 2019; 15:e1007213. [PMID: 31356591 PMCID: PMC6687210 DOI: 10.1371/journal.pcbi.1007213] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 08/08/2019] [Accepted: 06/27/2019] [Indexed: 01/01/2023] Open
Abstract
Mollusk shells are an ideal model system for understanding the morpho-elastic basis of morphological evolution of invertebrates’ exoskeletons. During the formation of the shell, the mantle tissue secretes proteins and minerals that calcify to form a new incremental layer of the exoskeleton. Most of the existing literature on the morphology of mollusks is descriptive. The mathematical understanding of the underlying coupling between pre-existing shell morphology, de novo surface deposition and morpho-elastic volume growth is at a nascent stage, primarily limited to reduced geometric representations. Here, we propose a general, three-dimensional computational framework coupling pre-existing morphology, incremental surface growth by accretion, and morpho-elastic volume growth. We exercise this framework by applying it to explain the stepwise morphogenesis of seashells during growth: new material surfaces are laid down by accretive growth on the mantle whose form is determined by its morpho-elastic growth. Calcification of the newest surfaces extends the shell as well as creates a new scaffold that constrains the next growth step. We study the effects of surface and volumetric growth rates, and of previously deposited shell geometries on the resulting modes of mantle deformation, and therefore of the developing shell’s morphology. Connections are made to a range of complex shells ornamentations. Molluska are the second most diversified phylum of the animal kingdom, and their evolutionary success can be partly attributed to the hard shell that provides both protection and support to the soft body. The distinctive anatomical features of these hard shells are their rich pigmentation patterns and complex structural ornamentations. While the pigmentation patterns are primarily of biochemical origin, the ornamentations result from mechanical deformation of the mantle due to growth induced forces. This mechanical basis of “growth and form” has been previously investigated using simplified morpho-mechanical models, but restricted to reduced geometric representations. Here we propose a three-dimensional computational framework coupling morphology, incremental surface growth by accretion, and morpho-elastic volume growth, to enable an improved representation of the growth and structural parameters controlling the evolution of these ornamentations. We study the effects of growth rates, and of previously deposited shell geometries on the resulting modes of mantle deformation, and present a “phase diagram” of morphogenesis in molluskan shells. Our main motivation for focusing on generic physical processes involved in development is that they may shape living beings in a predictive way and partly determine the spectrum of forms that have been and could have been generated during evolution.
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Affiliation(s)
- Shiva Rudraraju
- Department of Mechanical Engineering, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Derek E. Moulton
- Mathematical Institute, University of Oxford, Oxford, United Kingdom
| | - Régis Chirat
- UMR CNRS 5276 LGL-TPE, Université Lyon1, 69622 Villeurbanne Cedex, France
| | - Alain Goriely
- Mathematical Institute, University of Oxford, Oxford, United Kingdom
| | - Krishna Garikipati
- Departments of Mechanical Engineering and Mathematics, Michigan Institute for Computational Discovery & Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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Hilgers L, Hartmann S, Hofreiter M, von Rintelen T. Novel Genes, Ancient Genes, and Gene Co-Option Contributed to the Genetic Basis of the Radula, a Molluscan Innovation. Mol Biol Evol 2019; 35:1638-1652. [PMID: 29672732 PMCID: PMC5995198 DOI: 10.1093/molbev/msy052] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The radula is the central foraging organ and apomorphy of the Mollusca. However, in contrast to other innovations, including the mollusk shell, genetic underpinnings of radula formation remain virtually unknown. Here, we present the first radula formative tissue transcriptome using the viviparous freshwater snail Tylomelania sarasinorum and compare it to foot tissue and the shell-building mantle of the same species. We combine differential expression, functional enrichment, and phylostratigraphic analyses to identify both specific and shared genetic underpinnings of the three tissues as well as their dominant functions and evolutionary origins. Gene expression of radula formative tissue is very distinct, but nevertheless more similar to mantle than to foot. Generally, the genetic bases of both radula and shell formation were shaped by novel orchestration of preexisting genes and continuous evolution of novel genes. A significantly increased proportion of radula-specific genes originated since the origin of stem-mollusks, indicating that novel genes were especially important for radula evolution. Genes with radula-specific expression in our study are frequently also expressed during the formation of other lophotrochozoan hard structures, like chaetae (hes1, arx), spicules (gbx), and shells of mollusks (gbx, heph) and brachiopods (heph), suggesting gene co-option for hard structure formation. Finally, a Lophotrochozoa-specific chitin synthase with a myosin motor domain (CS-MD), which is expressed during mollusk and brachiopod shell formation, had radula-specific expression in our study. CS-MD potentially facilitated the construction of complex chitinous structures and points at the potential of molecular novelties to promote the evolution of different morphological innovations.
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Affiliation(s)
- Leon Hilgers
- Museum für Naturkunde Berlin, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
- Adaptive Evolutionary Genomics Department, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
- Corresponding author: E-mail:
| | - Stefanie Hartmann
- Adaptive Evolutionary Genomics Department, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Michael Hofreiter
- Adaptive Evolutionary Genomics Department, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Thomas von Rintelen
- Museum für Naturkunde Berlin, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
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Sumner-Rooney L, Sigwart JD. Do chitons have a brain? New evidence for diversity and complexity in the polyplacophoran central nervous system. J Morphol 2018; 279:936-949. [PMID: 29683195 DOI: 10.1002/jmor.20823] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 03/19/2018] [Accepted: 03/22/2018] [Indexed: 01/26/2023]
Abstract
Molluscs demonstrate astonishing morphological diversity, and the relationships among clades have been debated for more than a century. Molluscan nervous systems range from simple 'ladder-like' cords to the complex brains of cephalopods. Chitons (Polyplacophora) are assumed to retain many molluscan plesiomorphies, lacking neural condensation and ganglionic structure, and therefore a brain. We reconstructed three-dimensional anatomical models of the nervous system in eight species of chitons in an attempt to clarify chiton neuroarchitecture and its variability. We combined new data with digitised historic slide material originally used by malacologist Johannes Thiele (1860-1935). Reconstructions of whole nervous systems in Acanthochitona fascicularis, Callochiton septemvalvis, Chiton olivaceus, Hemiarthrum setulosum, Lepidochitona cinerea, Lepidopleurus cajetanus and Leptochiton asellus, and the anterior nervous system of Schizoplax brandtii, demonstrated consistent and substantial anterior neural concentration in the circumoesophageal nerve ring. This is further organised into three concentric tracts, corresponding to the lateral, ventral and cerebral nerve cords. These represent homologues to the three main pairs of ganglia in other molluscs. Their relative size, shape and organisation are highly variable among the examined taxa, but consistent with previous studies of select species, and we formulated a set of neuroanatomical characters for chitons. These support anatomical transitions at the ordinal and subordinal levels; the identification of robust homologies in neural architecture will be central to future comparisons across Mollusca and, more broadly, Lophotrochozoa. Contrary to almost all previous descriptions, the size and structure of the chiton anterior nerve ring unambiguously qualify it as a true brain with cordal substructure.
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Affiliation(s)
- Lauren Sumner-Rooney
- Oxford University Museum of Natural History, Oxford, United Kingdom.,Museum für Naturkunde, Berlin, Germany
| | - Julia D Sigwart
- Queen's University Marine Laboratory, Portaferry, Northern Ireland.,Museum of Paleontology, University of California Berkeley, Berkeley, California
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