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Randall JG, Gatesy J, McGowen MR, Springer MS. Molecular Evidence for Relaxed Selection on the Enamel Genes of Toothed Whales (Odontoceti) with Degenerative Enamel Phenotypes. Genes (Basel) 2024; 15:228. [PMID: 38397217 PMCID: PMC10888366 DOI: 10.3390/genes15020228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 02/06/2024] [Accepted: 02/07/2024] [Indexed: 02/25/2024] Open
Abstract
Different species of toothed whales (Odontoceti) exhibit a variety of tooth forms and enamel types. Some odontocetes have highly prismatic enamel with Hunter-Schreger bands, whereas enamel is vestigial or entirely lacking in other species. Different tooth forms and enamel types are associated with alternate feeding strategies that range from biting and grasping prey with teeth in most oceanic and river dolphins to the suction feeding of softer prey items without the use of teeth in many beaked whales. At the molecular level, previous studies have documented inactivating mutations in the enamel-specific genes of some odontocete species that lack complex enamel. At a broader scale, however, it is unclear whether enamel complexity across the full diversity of extant Odontoceti correlates with the relative strength of purifying selection on enamel-specific genes. Here, we employ sequence alignments for seven enamel-specific genes (ACP4, AMBN, AMELX, AMTN, ENAM, KLK4, MMP20) in 62 odontocete species that are representative of all extant families. The sequences for 33 odontocete species were obtained from databases, and sequences for the remaining 29 species were newly generated for this study. We screened these alignments for inactivating mutations (e.g., frameshift indels) and provide a comprehensive catalog of these mutations in species with one or more inactivated enamel genes. Inactivating mutations are rare in Delphinidae (oceanic dolphins) and Platanistidae/Inioidea (river dolphins) that have higher enamel complexity scores. By contrast, mutations are much more numerous in clades such as Monodontidae (narwhal, beluga), Ziphiidae (beaked whales), Physeteroidea (sperm whales), and Phocoenidae (porpoises) that are characterized by simpler enamel or even enamelless teeth. Further, several higher-level taxa (e.g., Hyperoodon, Kogiidae, Monodontidae) possess shared inactivating mutations in one or more enamel genes, which suggests loss of function of these genes in the common ancestor of each clade. We also performed selection (dN/dS) analyses on a concatenation of these genes and used linear regression and Spearman's rank-order correlation to test for correlations between enamel complexity and two different measures of selection intensity (# of inactivating mutations per million years, dN/dS values). Selection analyses revealed that relaxed purifying selection is especially prominent in physeteroids, monodontids, and phocoenids. Linear regressions and correlation analyses revealed a strong negative correlation between selective pressure (dN/dS values) and enamel complexity. Stronger purifying selection (low dN/dS) is found on branches with more complex enamel and weaker purifying selection (higher dN/dS) occurs on branches with less complex enamel or enamelless teeth. As odontocetes diversified into a variety of feeding modes, in particular, the suction capture of prey, a reduced reliance on the dentition for prey capture resulted in the relaxed selection of genes that are critical to enamel development.
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Affiliation(s)
- Jason G. Randall
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA;
| | - John Gatesy
- Division of Vertebrate Zoology, American Museum of Natural History, New York, NY 10024, USA;
| | - Michael R. McGowen
- Department of Vertebrate Zoology, Smithsonian National Museum of Natural History, MRC 108, P.O. Box 37012, Washington, DC 20013, USA;
| | - Mark S. Springer
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA;
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2
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Morin PA, Martien KK, Lang AR, Hancock-Hanser BL, Pease VL, Robertson KM, Sattler M, Slikas E, Rosel PE, Baker CS, Taylor BL, Archer FI. Guidelines and quantitative standards for improved cetacean taxonomy using full mitochondrial genomes. J Hered 2023; 114:612-624. [PMID: 37647537 DOI: 10.1093/jhered/esad049] [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: 01/31/2023] [Accepted: 08/28/2023] [Indexed: 09/01/2023] Open
Abstract
In many organisms, especially those of conservation concern, traditional lines of evidence for taxonomic delineation, such as morphological data, are often difficult to obtain. In these cases, genetic data are often the only source of information available for taxonomic studies. In particular, population surveys of mitochondrial genomes offer increased resolution and precision in support of taxonomic decisions relative to conventional use of the control region or other gene fragments of the mitochondrial genome. To improve quantitative guidelines for taxonomic decisions in cetaceans, we build on a previous effort targeting the control region and evaluate, for whole mitogenome sequences, a suite of divergence and diagnosability estimates for pairs of recognized cetacean populations, subspecies, and species. From this overview, we recommend new guidelines based on complete mitogenomes, combined with other types of evidence for isolation and divergence, which will improve resolution for taxonomic decisions, especially in the face of small sample sizes or low levels of genetic diversity. We further use simulated data to assist interpretations of divergence in the context of varying forms of historical demography, culture, and ecology.
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Affiliation(s)
- Phillip A Morin
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA, United States
| | - Karen K Martien
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA, United States
| | - Aimee R Lang
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA, United States
| | - Brittany L Hancock-Hanser
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA, United States
| | - Victoria L Pease
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA, United States
| | - Kelly M Robertson
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA, United States
| | - Maya Sattler
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA, United States
| | - Elizabeth Slikas
- School of Life Sciences, Center for Evolution and Medicine, Arizona State University, Tempe, AZ, United States
| | - Patricia E Rosel
- Marine Mammal and Turtle Division, Southeast Fisheries Science Center, National Marine Fisheries Service, NOAA, Lafayette, LA, United States
| | - C Scott Baker
- Marine Mammal Institute, Oregon State University, Newport, OR, United States
| | - Barbara L Taylor
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA, United States
| | - Frederick I Archer
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA, United States
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3
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Ku JE, Choi SG. Population Structure of Finless Porpoise (Neophocaena phocaenoides) Discovered off Coastal Waters, Republic of Korea. Genes (Basel) 2022; 13:genes13101701. [PMID: 36292586 PMCID: PMC9602366 DOI: 10.3390/genes13101701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/08/2022] [Accepted: 09/19/2022] [Indexed: 11/16/2022] Open
Abstract
The finless porpoise (Neophocaena phocaenoides Cuvier, 1829) is distributed in the coastal waters of Asia, throughout Indonesia to the east, and as far north as the Taiwan Strait. The finless porpoise has been declared critically endangered by the WWF (World Wide Fund for Nature), and in 2017 was rated vulnerable on the IUCN Red Threatened Species List. Since this species is distributed near the coast and has many interactions with humans, effective conservation of the species requires further studies into their genetic diversity and population. In this study, 45 samples were obtained from bycatch or stranded individuals in the East, South, and West Seas, where Korean porpoises were mainly distributed from 2017–2021. We compared 473 bp mtDNA sequences from the control region. Pairwise fixation indices (FST) revealed that the two populations differed significantly (FST = 0.4557, p = 0.000). In contrast to high levels of genetic differentiation, gene flow was identified as medium levels (Nm of 0.04–0.71). Our data suggest that finless porpoises may have undergone a historic differentiation event, and that finless porpoises in the three regions could be divided into two populations: West and East/South.
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Gillet A, Frédérich B, Pierce SE, Parmentier E. Iterative Habitat Transitions are Associated with Morphological Convergence of the Backbone in Delphinoids. J MAMM EVOL 2022. [DOI: 10.1007/s10914-022-09615-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Robinson JA, Kyriazis CC, Nigenda-Morales SF, Beichman AC, Rojas-Bracho L, Robertson KM, Fontaine MC, Wayne RK, Lohmueller KE, Taylor BL, Morin PA. The critically endangered vaquita is not doomed to extinction by inbreeding depression. Science 2022; 376:635-639. [PMID: 35511971 PMCID: PMC9881057 DOI: 10.1126/science.abm1742] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In cases of severe wildlife population decline, a key question is whether recovery efforts will be impeded by genetic factors, such as inbreeding depression. Decades of excess mortality from gillnet fishing have driven Mexico's vaquita porpoise (Phocoena sinus) to ~10 remaining individuals. We analyzed whole-genome sequences from 20 vaquitas and integrated genomic and demographic information into stochastic, individual-based simulations to quantify the species' recovery potential. Our analysis suggests that the vaquita's historical rarity has resulted in a low burden of segregating deleterious variation, reducing the risk of inbreeding depression. Similarly, genome-informed simulations suggest that the vaquita can recover if bycatch mortality is immediately halted. This study provides hope for vaquitas and other naturally rare endangered species and highlights the utility of genomics in predicting extinction risk.
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Affiliation(s)
- Jacqueline A. Robinson
- Institute for Human Genetics, University of California, San Francisco; San Francisco, CA, USA
| | - Christopher C. Kyriazis
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles; Los Angeles, CA, USA
| | - Sergio F. Nigenda-Morales
- Advanced Genomics Unit, National Laboratory of Genomics for Biodiversity (Langebio), Center for Research and Advanced Studies (Cinvestav); Irapuato, Guanajuato, Mexico
| | | | - Lorenzo Rojas-Bracho
- Comisión Nacional de Áreas Naturales Protegidas/SEMARNAT; Ensenada, Mexico
- PNUD-Sinergia en la Comisión Nacional de Áreas Naturales Protegidas, Ensenada, B.C., México
| | - Kelly M. Robertson
- Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA ; La Jolla, CA, USA
| | - Michael C. Fontaine
- MIVEGEC, Université de Montpellier, CNRS, IRD; Montpellier, France
- Centre de Recherche en Écologie et Évolution de la Santé (CREES); Montpellier, France
- Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen; Groningen, The Netherlands
| | - Robert K. Wayne
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles; Los Angeles, CA, USA
| | - Kirk E. Lohmueller
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles; Los Angeles, CA, USA
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles; Los Angeles, CA, USA
| | - Barbara L. Taylor
- Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA ; La Jolla, CA, USA
| | - Phillip A. Morin
- Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA ; La Jolla, CA, USA
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6
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Marchesi MC, Galatius A, Zaffino M, Coscarella MA, González-José R. Vertebral morphology in extant porpoises: radiation and functional implications. J Morphol 2021; 283:273-286. [PMID: 34962309 DOI: 10.1002/jmor.21441] [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: 11/24/2021] [Revised: 12/21/2021] [Accepted: 12/26/2021] [Indexed: 11/07/2022]
Abstract
Vertebral morphology has profound biomechanical implications and plays an important role in adaptation to different habitats and foraging strategies for cetaceans. Extant porpoise species (Phocoenidae) display analogous evolutionary patterns in both hemispheres associated with convergent evolution to coastal versus oceanic environments. We employed 3D geometric morphometrics to study vertebral morphology in five porpoise species with contrasting habitats: the coastal Indo-Pacific finless porpoise (Neophocaena phocaenoides); the mostly coastal harbor porpoise (Phocoena phocoena) and Burmeister's porpoise (Phocoena spinipinnis); and the oceanic spectacled porpoise (Phocoena dioptrica) and Dall's porpoise (Phocoenoides dalli). We evaluated the radiation of vertebral morphology, both in size and shape, using multivariate statistics. We supplemented data with samples of an early-radiating delphinoid species, the narwhal (Monodon monoceros); and an early-radiating delphinid species, the white-beaked dolphin (Lagenorhynchus albirostris). Principal component analyses were used to map shape variation onto phylogenies, and phylogenetic constraints were investigated through permutation tests. We established links between vertebral morphology and movement patterns through biomechanical inferences from morphological presentations. We evidenced divergence in size between species with contrasting habitats, with coastal species tending to decrease in size from their estimated ancestral state, and oceanic species tending to increase in size. Regarding vertebral shape, coastal species had longer centra and shorter neural processes, but longer transverse processes, whilst oceanic species tended to have disk-shaped vertebrae with longer neural processes. Within Phocoenidae, the absence of phylogenetic constraints in vertebral morphology suggests a high level of evolutionary lability. Overall, our results are in accordance with the hypothesis of speciation within the family from a coastal ancestor, through adaptation to particular habitats. Variation in vertebral morphology in this group of small odontocetes highlights the importance of environmental complexity and particular selective pressures for the speciation process through the development of adaptations that minimize energetic costs during locomotion and prey capture. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- María Constanza Marchesi
- Laboratorio de Mamíferos Marinos, Centro para el Estudio de los Sistemas Marinos (CESIMAR), CCT CONICET-CENPAT, Puerto Madryn, Argentina
| | - Anders Galatius
- Section for Marine Mammal Research, Department of Ecoscience, Aarhus University, Roskilde, Denmark
| | - Martina Zaffino
- Universidad Nacional de la Patagonia San Juan Bosco, Puerto Madryn, Argentina
| | - Mariano Alberto Coscarella
- Laboratorio de Mamíferos Marinos, Centro para el Estudio de los Sistemas Marinos (CESIMAR), CCT CONICET-CENPAT, Puerto Madryn, Argentina.,Universidad Nacional de la Patagonia San Juan Bosco, Puerto Madryn, Argentina
| | - Rolando González-José
- Instituto Patagónico de Ciencias Sociales y Humanas (IPCSH), CCT CONICET CENPAT, Puerto Madryn, Argentina
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7
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Guinand B, Oral M, Tougard C. Brown trout phylogenetics: A persistent mirage towards (too) many species. JOURNAL OF FISH BIOLOGY 2021; 99:298-307. [PMID: 33483952 DOI: 10.1111/jfb.14686] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/28/2020] [Accepted: 01/19/2021] [Indexed: 06/12/2023]
Affiliation(s)
- Bruno Guinand
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Münevver Oral
- Faculty of Fisheries and Aquatic Science, Recep Tayyip Erdogan University, Rize, Turkey
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8
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Ben Chehida Y, Loughnane R, Thumloup J, Kaschner K, Garilao C, Rosel PE, Fontaine MC. No leading-edge effect in North Atlantic harbor porpoises: Evolutionary and conservation implications. Evol Appl 2021; 14:1588-1611. [PMID: 34178106 PMCID: PMC8210799 DOI: 10.1111/eva.13227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/19/2021] [Accepted: 02/24/2021] [Indexed: 01/12/2023] Open
Abstract
Understanding species responses to past environmental changes can help forecast how they will cope with ongoing climate changes. Harbor porpoises are widely distributed in the North Atlantic and were deeply impacted by the Pleistocene changes with the split of three subspecies. Despite major impacts of fisheries on natural populations, little is known about population connectivity and dispersal, how they reacted to the Pleistocene changes, and how they will evolve in the future. Here, we used phylogenetics, population genetics, and predictive habitat modeling to investigate population structure and phylogeographic history of the North Atlantic porpoises. A total of 925 porpoises were characterized at 10 microsatellite loci and one quarter of the mitogenome (mtDNA). A highly divergent mtDNA lineage was uncovered in one porpoise off Western Greenland, suggesting that a cryptic group may occur and could belong to a recently discovered mesopelagic ecotype off Greenland. Aside from it and the southern subspecies, spatial genetic variation showed that porpoises from both sides of the North Atlantic form a continuous system belonging to the same subspecies (Phocoena phocoena phocoena). Yet, we identified important departures from random mating and restricted dispersal forming a highly significant isolation by distance (IBD) at both mtDNA and nuclear markers. A ten times stronger IBD at mtDNA compared with nuclear loci supported previous evidence of female philopatry. Together with the lack of spatial trends in genetic diversity, this IBD suggests that migration-drift equilibrium has been reached, erasing any genetic signal of a leading-edge effect that accompanied the predicted recolonization of the northern habitats freed from Pleistocene ice. These results illuminate the processes shaping porpoise population structure and provide a framework for designing conservation strategies and forecasting future population evolution.
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Affiliation(s)
- Yacine Ben Chehida
- Groningen Institute for Evolutionary Life Sciences (GELIFES)University of GroningenGroningenThe Netherlands
| | - Roisin Loughnane
- Groningen Institute for Evolutionary Life Sciences (GELIFES)University of GroningenGroningenThe Netherlands
| | - Julie Thumloup
- Groningen Institute for Evolutionary Life Sciences (GELIFES)University of GroningenGroningenThe Netherlands
| | - Kristin Kaschner
- Department of Biometry and Environmental System AnalysisFaculty of Environment and Natural ResourcesUniversity of FreiburgFreiburgGermany
| | | | - Patricia E. Rosel
- Southeast Fisheries Science CenterNational Marine Fisheries ServiceNOAALafayetteLAUSA
| | - Michael C. Fontaine
- Groningen Institute for Evolutionary Life Sciences (GELIFES)University of GroningenGroningenThe Netherlands
- Laboratoire MIVEGEC (Université de Montpellier, CNRS, IRD)Montpellier Cedex 5France
- Centre de Recherche en Écologie et Évolution de la Santé (CREESMontpellier Cedex 5France
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9
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Morin PA, Forester BR, Forney KA, Crossman CA, Hancock-Hanser BL, Robertson KM, Barrett-Lennard LG, Baird RW, Calambokidis J, Gearin P, Hanson MB, Schumacher C, Harkins T, Fontaine MC, Taylor BL, Parsons KM. Population structure in a continuously distributed coastal marine species, the harbor porpoise, based on microhaplotypes derived from poor-quality samples. Mol Ecol 2021; 30:1457-1476. [PMID: 33544423 DOI: 10.1111/mec.15827] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 01/20/2021] [Accepted: 01/27/2021] [Indexed: 12/24/2022]
Abstract
Harbor porpoise in the North Pacific are found in coastal waters from southern California to Japan, but population structure is poorly known outside of a few local areas. We used multiplexed amplicon sequencing of 292 loci and genotyped clusters of single nucleotide polymoirphisms as microhaplotypes (N = 271 samples) in addition to mitochondrial (mtDNA) sequence data (N = 413 samples) to examine the genetic structure from samples collected along the Pacific coast and inland waterways from California to southern British Columbia. We confirmed an overall pattern of strong isolation-by-distance, suggesting that individual dispersal is restricted. We also found evidence of regions where genetic differences are larger than expected based on geographical distance alone, implying current or historical barriers to gene flow. In particular, the southernmost population in California is genetically distinct (FST = 0.02 [microhaplotypes]; 0.31 [mtDNA]), with both reduced genetic variability and high frequency of an otherwise rare mtDNA haplotype. At the northern end of our study range, we found significant genetic differentiation of samples from the Strait of Georgia, previously identified as a potential biogeographical boundary or secondary contact zone between harbor porpoise populations. Association of microhaplotypes with remotely sensed environmental variables indicated potential local adaptation, especially at the southern end of the species' range. These results inform conservation and management for this nearshore species, illustrate the value of genomic methods for detecting patterns of genetic structure within a continuously distributed marine species, and highlight the power of microhaplotype genotyping for detecting genetic structure in harbor porpoises despite reliance on poor-quality samples.
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Affiliation(s)
- Phillip A Morin
- Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA, USA
| | - Brenna R Forester
- Department of Biology, Colorado State University, Fort Collins, CO, USA
| | - Karin A Forney
- Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, Moss Landing, CA, USA.,Moss Landing Marine Laboratories, San Jose State University, Moss Landing, CA, USA
| | - Carla A Crossman
- Biology Department, Saint Mary's University, Halifax, NS, Canada.,Cetacean Research Program, Vancouver Aquarium, Vancouver, BC, Canada
| | | | - Kelly M Robertson
- Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA, USA
| | | | | | | | - Pat Gearin
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, WA, USA
| | - M Bradley Hanson
- Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, WA, USA
| | | | | | - Michael C Fontaine
- MIVEGEC Research Unit (Université de Montpellier, CNRS, IRD) & Centre for Research on the Ecology and Evolution of Diseases (CREES), Centre IRD de Montpellier, Montpellier, France.,Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
| | - Barbara L Taylor
- Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA, USA
| | - Kim M Parsons
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, WA, USA.,Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, WA, USA
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10
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Fresh water skin disease in dolphins: a case definition based on pathology and environmental factors in Australia. Sci Rep 2020; 10:21979. [PMID: 33319842 PMCID: PMC7738556 DOI: 10.1038/s41598-020-78858-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 11/30/2020] [Indexed: 11/17/2022] Open
Abstract
A distinct ulcerative dermatitis known as “freshwater skin disease” is an emerging clinical and pathological presentation in coastal cetaceans worldwide. In Australia, two remarkably similar mortality events enabled the creation of a case definition based on pathology and environmental factors. The first affected a community of endemic Tursiops australis in the Gippsland Lakes, Victoria, while the second occurred among T. aduncus resident in the Swan-Canning River system, Western Australia. The common features of both events were (1) an abrupt and marked decrease in salinity (from > 30ppt to < 5ppt) due to rainfall in the catchments, with hypo-salinity persisting weeks to months, and (2) dermatitis characterized grossly by patchy skin pallor that progressed to variable circular or targetoid, often raised, and centrally ulcerated lesions covering up to 70% of the body surface. The affected skin was often colonized by a variety of fungal, bacterial and algal species that imparted variable yellow, green or orange discoloration. Histologic lesions consisted of epidermal hydropic change leading to vesiculation and erosion; alternately, or in addition, the formation of intra-epithelial pustules resulting in ulceration and hypodermal necrosis. Thus, the environmental factors and characteristic pathologic lesions, are necessary components of the case definition for freshwater skin disease.
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11
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Morin PA, Archer FI, Avila CD, Balacco JR, Bukhman YV, Chow W, Fedrigo O, Formenti G, Fronczek JA, Fungtammasan A, Gulland FMD, Haase B, Peter Heide-Jorgensen M, Houck ML, Howe K, Misuraca AC, Mountcastle J, Musser W, Paez S, Pelan S, Phillippy A, Rhie A, Robinson J, Rojas-Bracho L, Rowles TK, Ryder OA, Smith CR, Stevenson S, Taylor BL, Teilmann J, Torrance J, Wells RS, Westgate AJ, Jarvis ED. Reference genome and demographic history of the most endangered marine mammal, the vaquita. Mol Ecol Resour 2020; 21:1008-1020. [PMID: 33089966 PMCID: PMC8247363 DOI: 10.1111/1755-0998.13284] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 09/08/2020] [Accepted: 10/08/2020] [Indexed: 12/12/2022]
Abstract
The vaquita is the most critically endangered marine mammal, with fewer than 19 remaining in the wild. First described in 1958, the vaquita has been in rapid decline for more than 20 years resulting from inadvertent deaths due to the increasing use of large-mesh gillnets. To understand the evolutionary and demographic history of the vaquita, we used combined long-read sequencing and long-range scaffolding methods with long- and short-read RNA sequencing to generate a near error-free annotated reference genome assembly from cell lines derived from a female individual. The genome assembly consists of 99.92% of the assembled sequence contained in 21 nearly gapless chromosome-length autosome scaffolds and the X-chromosome scaffold, with a scaffold N50 of 115 Mb. Genome-wide heterozygosity is the lowest (0.01%) of any mammalian species analysed to date, but heterozygosity is evenly distributed across the chromosomes, consistent with long-term small population size at genetic equilibrium, rather than low diversity resulting from a recent population bottleneck or inbreeding. Historical demography of the vaquita indicates long-term population stability at less than 5,000 (Ne) for over 200,000 years. Together, these analyses indicate that the vaquita genome has had ample opportunity to purge highly deleterious alleles and potentially maintain diversity necessary for population health.
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Affiliation(s)
- Phillip A Morin
- Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA, USA
| | - Frederick I Archer
- Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA, USA
| | - Catherine D Avila
- San Diego Zoo Institute for Conservation Research, Escondido, CA, USA
| | - Jennifer R Balacco
- Vertebrate Genome Laboratory, The Rockefeller University, New York, NY, USA
| | - Yury V Bukhman
- Regenerative Biology, Morgridge Institute for Research, Madison, WI, USA
| | | | - Olivier Fedrigo
- Vertebrate Genome Laboratory, The Rockefeller University, New York, NY, USA
| | - Giulio Formenti
- Vertebrate Genome Laboratory, The Rockefeller University, New York, NY, USA
| | - Julie A Fronczek
- San Diego Zoo Institute for Conservation Research, Escondido, CA, USA
| | | | | | - Bettina Haase
- Vertebrate Genome Laboratory, The Rockefeller University, New York, NY, USA
| | | | - Marlys L Houck
- San Diego Zoo Institute for Conservation Research, Escondido, CA, USA
| | | | - Ann C Misuraca
- San Diego Zoo Institute for Conservation Research, Escondido, CA, USA
| | | | | | - Sadye Paez
- Laboratory of Neurogenetics of Language, The Rockefeller University, New York, NY, USA
| | | | - Adam Phillippy
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, Bethesda, MD, USA
| | - Arang Rhie
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, Bethesda, MD, USA
| | - Jacqueline Robinson
- Institute for Human Genetics, University of California, San Francisco, CA, USA
| | | | - Teri K Rowles
- Office of Protected Resources, National Marine Fisheries Service, NOAA, Silver Spring, MD, USA
| | - Oliver A Ryder
- San Diego Zoo Institute for Conservation Research, Escondido, CA, USA
| | | | | | - Barbara L Taylor
- Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, CA, USA
| | - Jonas Teilmann
- Marine Mammal Research, Department of Bioscience, Aarhus University, Roskilde, Denmark
| | | | - Randall S Wells
- Chicago Zoological Society's Sarasota Dolphin Research Program, c/o Mote Marine Laboratory, Sarasota, FL, USA
| | | | - Erich D Jarvis
- Laboratory of Neurogenetics of Language, The Rockefeller University, New York, NY, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
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