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Goodheart JA, Rio RA, Taraporevala NF, Fiorenza RA, Barnes SR, Morrill K, Jacob MAC, Whitesel C, Masterson P, Batzel GO, Johnston HT, Ramirez MD, Katz PS, Lyons DC. A chromosome-level genome for the nudibranch gastropod Berghia stephanieae helps parse clade-specific gene expression in novel and conserved phenotypes. BMC Biol 2024; 22:9. [PMID: 38233809 PMCID: PMC10795318 DOI: 10.1186/s12915-024-01814-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 01/03/2024] [Indexed: 01/19/2024] Open
Abstract
BACKGROUND How novel phenotypes originate from conserved genes, processes, and tissues remains a major question in biology. Research that sets out to answer this question often focuses on the conserved genes and processes involved, an approach that explicitly excludes the impact of genetic elements that may be classified as clade-specific, even though many of these genes are known to be important for many novel, or clade-restricted, phenotypes. This is especially true for understudied phyla such as mollusks, where limited genomic and functional biology resources for members of this phylum have long hindered assessments of genetic homology and function. To address this gap, we constructed a chromosome-level genome for the gastropod Berghia stephanieae (Valdés, 2005) to investigate the expression of clade-specific genes across both novel and conserved tissue types in this species. RESULTS The final assembled and filtered Berghia genome is comparable to other high-quality mollusk genomes in terms of size (1.05 Gb) and number of predicted genes (24,960 genes) and is highly contiguous. The proportion of upregulated, clade-specific genes varied across tissues, but with no clear trend between the proportion of clade-specific genes and the novelty of the tissue. However, more complex tissue like the brain had the highest total number of upregulated, clade-specific genes, though the ratio of upregulated clade-specific genes to the total number of upregulated genes was low. CONCLUSIONS Our results, when combined with previous research on the impact of novel genes on phenotypic evolution, highlight the fact that the complexity of the novel tissue or behavior, the type of novelty, and the developmental timing of evolutionary modifications will all influence how novel and conserved genes interact to generate diversity.
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Affiliation(s)
- Jessica A Goodheart
- Division of Invertebrate Zoology, American Museum of Natural History, New York, NY, USA.
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA.
| | - Robin A Rio
- Bioengineering Department, Stanford University, Stanford, CA, USA
| | - Neville F Taraporevala
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
- Department of Wildland Resources, Utah State University, Logan, UT, USA
| | - Rose A Fiorenza
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Seth R Barnes
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Kevin Morrill
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Mark Allan C Jacob
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Carl Whitesel
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Park Masterson
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Grant O Batzel
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Hereroa T Johnston
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - M Desmond Ramirez
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, USA
- Institute of Neuroscience, University of Oregon, Eugene, OR, USA
| | - Paul S Katz
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Deirdre C Lyons
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA.
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Goodheart JA, Rio RA, Taraporevala NF, Fiorenza RA, Barnes SR, Morrill K, Jacob MAC, Whitesel C, Masterson P, Batzel GO, Johnston HT, Ramirez MD, Katz PS, Lyons DC. A chromosome-level genome for the nudibranch gastropod Berghia stephanieae helps parse clade-specific gene expression in novel and conserved phenotypes. bioRxiv 2023:2023.08.04.552006. [PMID: 38014205 PMCID: PMC10680569 DOI: 10.1101/2023.08.04.552006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
How novel phenotypes originate from conserved genes, processes, and tissues remains a major question in biology. Research that sets out to answer this question often focuses on the conserved genes and processes involved, an approach that explicitly excludes the impact of genetic elements that may be classified as clade-specific, even though many of these genes are known to be important for many novel, or clade-restricted, phenotypes. This is especially true for understudied phyla such as mollusks, where limited genomic and functional biology resources for members of this phylum has long hindered assessments of genetic homology and function. To address this gap, we constructed a chromosome-level genome for the gastropod Berghia stephanieae (Valdés, 2005) to investigate the expression of clade-specific genes across both novel and conserved tissue types in this species. The final assembled and filtered Berghia genome is comparable to other high quality mollusk genomes in terms of size (1.05 Gb) and number of predicted genes (24,960 genes), and is highly contiguous. The proportion of upregulated, clade-specific genes varied across tissues, but with no clear trend between the proportion of clade-specific genes and the novelty of the tissue. However, more complex tissue like the brain had the highest total number of upregulated, clade-specific genes, though the ratio of upregulated clade-specific genes to the total number of upregulated genes was low. Our results, when combined with previous research on the impact of novel genes on phenotypic evolution, highlight the fact that the complexity of the novel tissue or behavior, the type of novelty, and the developmental timing of evolutionary modifications will all influence how novel and conserved genes interact to generate diversity.
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Affiliation(s)
- Jessica A. Goodheart
- Division of Invertebrate Zoology, American Museum of Natural History, New York, NY USA
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Robin A. Rio
- Bioengineering Department, Stanford University, Stanford, CA, USA
| | - Neville F. Taraporevala
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
- Department of Wildland Resources, Utah State University, Logan, UT, USA
| | - Rose A. Fiorenza
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Seth R. Barnes
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Kevin Morrill
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Mark Allan C. Jacob
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Carl Whitesel
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Park Masterson
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Grant O. Batzel
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Hereroa T. Johnston
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - M. Desmond Ramirez
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Paul S. Katz
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Deirdre C. Lyons
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
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Taraporevala NF, Lesoway MP, Goodheart JA, Lyons DC. Precocious Sperm Exchange in the Simultaneously Hermaphroditic Nudibranch, Berghia stephanieae. Integr Org Biol 2022; 4:obac030. [PMID: 36089995 PMCID: PMC9449679 DOI: 10.1093/iob/obac034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 06/10/2022] [Accepted: 07/28/2022] [Indexed: 11/15/2022] Open
Abstract
Sexual systems vary greatly across molluscs. This diversity includes simultaneous hermaphroditism, with both sexes functional at the same time. Most nudibranch molluscs are thought to be simultaneous hermaphrodites, but detailed studies of reproductive development and timing remain rare as most species cannot be cultured in the lab. The aeolid nudibranch, Berghia stephanieae, is one such species that can be cultured through multiple generations on the benchtop. We studied B. stephanieae reproductive timing to establish when animals first exchange sperm and how long sperm can be stored. We isolated age- and size-matched individuals at sequential timepoints to learn how early individuals can exchange sperm. Individuals isolated at 10 weeks post initial feeding (wpf; ∼13 weeks postlaying [wpl]) can produce fertilized eggs. This is 6 weeks before animals first lay egg masses, indicating that sperm exchange occurs well before individuals are capable of laying eggs. Our results indicate that male gonads become functional for animals between 6 mm (∼6 wpf, ∼9 wpl) and 9 mm (∼12 wpf, ∼15 wpl) in length. That is much smaller (and sooner) than the size (and age) of individuals at first laying (12–19 mm; ∼16 wpf, ∼19 wpl), indicating that male and female functions do not develop simultaneously. We also tracked the number of fertilized eggs in each egg mass, which remained steady for the first 10–15 egg masses, followed by a decline to near-to-no fertilization. This dataset provides insights into the precise timing of the onset of functionality of the male and female reproductive systems in B. stephanieae. These data contribute to a broader understanding of reproductive development and the potential for understanding the evolution of diverse sexual systems in molluscs.
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Affiliation(s)
- Neville F Taraporevala
- Scripps Institution of Oceanography, University of California San Diego , 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Maryna P Lesoway
- Scripps Institution of Oceanography, University of California San Diego , 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Jessica A Goodheart
- Scripps Institution of Oceanography, University of California San Diego , 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Deirdre C Lyons
- Scripps Institution of Oceanography, University of California San Diego , 9500 Gilman Drive, La Jolla, CA 92093, USA
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