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Bianucci G, Lambert O, Urbina M, Merella M, Collareta A, Bennion R, Salas-Gismondi R, Benites-Palomino A, Post K, de Muizon C, Bosio G, Di Celma C, Malinverno E, Pierantoni PP, Villa IM, Amson E. A heavyweight early whale pushes the boundaries of vertebrate morphology. Nature 2023; 620:824-829. [PMID: 37532931 DOI: 10.1038/s41586-023-06381-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 06/28/2023] [Indexed: 08/04/2023]
Abstract
The fossil record of cetaceans documents how terrestrial animals acquired extreme adaptations and transitioned to a fully aquatic lifestyle1,2. In whales, this is associated with a substantial increase in maximum body size. Although an elongate body was acquired early in cetacean evolution3, the maximum body mass of baleen whales reflects a recent diversification that culminated in the blue whale4. More generally, hitherto known gigantism among aquatic tetrapods evolved within pelagic, active swimmers. Here we describe Perucetus colossus-a basilosaurid whale from the middle Eocene epoch of Peru. It displays, to our knowledge, the highest degree of bone mass increase known to date, an adaptation associated with shallow diving5. The estimated skeletal mass of P. colossus exceeds that of any known mammal or aquatic vertebrate. We show that the bone structure specializations of aquatic mammals are reflected in the scaling of skeletal fraction (skeletal mass versus whole-body mass) across the entire disparity of amniotes. We use the skeletal fraction to estimate the body mass of P. colossus, which proves to be a contender for the title of heaviest animal on record. Cetacean peak body mass had already been reached around 30 million years before previously assumed, in a coastal context in which primary productivity was particularly high.
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Affiliation(s)
- Giovanni Bianucci
- Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy
| | - Olivier Lambert
- D.O. Terre et Histoire de la Vie, Institut Royal des Sciences Naturelles de Belgique, Brussels, Belgium
| | - Mario Urbina
- Departamento de Paleontología de Vertebrados, Museo de Historia Natural-Universidad Nacional Mayor de San Marcos, Lima, Perú
| | - Marco Merella
- Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy
| | - Alberto Collareta
- Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy
| | - Rebecca Bennion
- D.O. Terre et Histoire de la Vie, Institut Royal des Sciences Naturelles de Belgique, Brussels, Belgium
- Evolution & Diversity Dynamics Lab, UR Geology, Université de Liège, Liège, Belgium
| | - Rodolfo Salas-Gismondi
- Departamento de Paleontología de Vertebrados, Museo de Historia Natural-Universidad Nacional Mayor de San Marcos, Lima, Perú
- Facultad de Ciencias y Filosofía/Centro de Investigación para el Desarrollo Integral y Sostenible, Laboratorios de Investigación y Desarrollo, Universitad Peruana Cayetano Heredia Lima, Lima, Perú
| | - Aldo Benites-Palomino
- Departamento de Paleontología de Vertebrados, Museo de Historia Natural-Universidad Nacional Mayor de San Marcos, Lima, Perú
- Department of Paleontology, University of Zurich, Zurich, Switzerland
| | - Klaas Post
- Natuurhistorisch Museum Rotterdam, Rotterdam, The Netherlands
| | - Christian de Muizon
- Département Origines et Évolution, CR2P (CNRS, MNHN, Sorbonne Université), Muséum National d'Histoire Naturelle, Paris, France
| | - Giulia Bosio
- Dipartimento di Scienze dell'Ambiente e della Terra, Università degli Studi di Milano-Bicocca, Milano, Italy
| | - Claudio Di Celma
- School of Science and Technology, University of Camerino, Camerino, Italy
| | - Elisa Malinverno
- Dipartimento di Scienze dell'Ambiente e della Terra, Università degli Studi di Milano-Bicocca, Milano, Italy
| | | | | | - Eli Amson
- Staatliches Museum für Naturkunde Stuttgart, Stuttgart, Germany.
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2
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Gônet J, Bardin J, Girondot M, Hutchinson JR, Laurin M. Locomotor and postural diversity among reptiles viewed through the prism of femoral microanatomy: Palaeobiological implications for some Permian and Mesozoic taxa. J Anat 2023; 242:891-916. [PMID: 36807199 PMCID: PMC10093171 DOI: 10.1111/joa.13833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 10/28/2022] [Accepted: 01/13/2023] [Indexed: 02/20/2023] Open
Abstract
The water-to-land transition by the first tetrapod vertebrates represents a key stage in their evolution. Selection pressures exerted by this new environment on animals led to the emergence of new locomotor and postural strategies that favoured access to different ecological niches and contributed to their evolutionary success. Today, amniotes show great locomotor and postural diversity, particularly among Reptilia, whose extant representatives include parasagittally locomoting erect and crouched bipeds (birds), sub-parasagittal 'semi-erect' quadrupeds (crocodylians) and sprawling quadrupeds (squamates and turtles). But the different steps leading to such diversity remain enigmatic and the type of locomotion adopted by many extinct species raises questions. This is notably the case of certain Triassic taxa such as Euparkeria and Marasuchus. The exploration of the bone microanatomy in reptiles could help to overcome these uncertainties. Indeed, this locomotor and postural diversity is accompanied by great microanatomical disparity. On land, the bones of the appendicular skeleton support the weight of the body and are subject to multiple constraints that partly shape their external and internal morphology. Here we show how microanatomical parameters measured in cross-section, such as bone compactness or the position of the medullocortical transition, can be related to locomotion. We hypothesised that this could be due to variations in cortical thickness. Using statistical methods that take phylogeny into account (phylogenetic flexible discriminant analyses), we develop different models of locomotion from a sample of femur cross-sections from 51 reptile species. We use these models to infer locomotion and posture in 7 extinct reptile taxa for which they remain debated or not fully clear. Our models produced reliable inferences for taxa that preceded and followed the quadruped/biped and sprawling/erect transitions, notably within the Captorhinidae and Dinosauria. For taxa contemporary with these transitions, such as Terrestrisuchus and Marasuchus, the inferences are more questionable. We use linear models to investigate the effect of body mass and functional ecology on our inference models. We show that body mass seems to significantly impact our model predictions in most cases, unlike the functional ecology. Finally, we illustrate how taphonomic processes can impact certain microanatomical parameters, especially the eccentricity of the section, while addressing some other potential limitations of our methods. Our study provides insight into the evolution of enigmatic locomotion in various early reptiles. Our models and methods could be used by palaeontologists to infer the locomotion and posture in other extinct reptile taxa, especially when considered in combination with other lines of evidence.
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Affiliation(s)
- Jordan Gônet
- Centre de recherche en paléontologie - Paris, UMR 7207, Sorbonne Université, Muséum national d'histoire naturelle, Centre national de la recherche scientifique, Paris, France
| | - Jérémie Bardin
- Centre de recherche en paléontologie - Paris, UMR 7207, Sorbonne Université, Muséum national d'histoire naturelle, Centre national de la recherche scientifique, Paris, France
| | - Marc Girondot
- Laboratoire écologie, systématique et évolution, UMR 8079, AgroParisTech, Université Paris-Saclay, Centre national de la recherche scientifique, Orsay, France
| | - John R Hutchinson
- Structure and Motion Laboratory, Royal Veterinary College, Department of Comparative Biomedical Sciences, Hatfield, UK
| | - Michel Laurin
- Centre de recherche en paléontologie - Paris, UMR 7207, Sorbonne Université, Muséum national d'histoire naturelle, Centre national de la recherche scientifique, Paris, France
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3
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Gônet J, Bardin J, Girondot M, Hutchinson JR, Laurin M. Unravelling the postural diversity of mammals: Contribution of humeral cross-sections to palaeobiological inferences. J MAMM EVOL 2023. [DOI: 10.1007/s10914-023-09652-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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4
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Sander PM, Griebeler EM, Klein N, Juarbe JV, Wintrich T, Revell LJ, Schmitz L. Early giant reveals faster evolution of large body size in ichthyosaurs than in cetaceans. Science 2021; 374:eabf5787. [PMID: 34941418 DOI: 10.1126/science.abf5787] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- P Martin Sander
- Abteilung Paläontologie, Institut für Geowissenschaften, Universität Bonn, 53115 Bonn, Germany.,The Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, CA 90007, USA
| | - Eva Maria Griebeler
- Institut für Organismische und Molekulare Evolutionsbiologie, Evolutionäre Ökologie, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Nicole Klein
- Abteilung Paläontologie, Institut für Geowissenschaften, Universität Bonn, 53115 Bonn, Germany
| | - Jorge Velez Juarbe
- Department of Mammalogy, Natural History Museum of Los Angeles County, Los Angeles, CA 90007, USA
| | - Tanja Wintrich
- Abteilung Paläontologie, Institut für Geowissenschaften, Universität Bonn, 53115 Bonn, Germany.,Anatomisches Institut, Universität Bonn, 53115 Bonn, Germany
| | - Liam J Revell
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA.,Universidad Católica de la Santísima Concepción, Concepción, Chile
| | - Lars Schmitz
- The Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, CA 90007, USA.,W.M. Keck Science Department of Claremont McKenna, Scripps, and Pitzer Colleges, Claremont, CA 91711, USA
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5
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Springer MS, Guerrero-Juarez CF, Huelsmann M, Collin MA, Danil K, McGowen MR, Oh JW, Ramos R, Hiller M, Plikus MV, Gatesy J. Genomic and anatomical comparisons of skin support independent adaptation to life in water by cetaceans and hippos. Curr Biol 2021; 31:2124-2139.e3. [PMID: 33798433 PMCID: PMC8154672 DOI: 10.1016/j.cub.2021.02.057] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 01/21/2021] [Accepted: 02/25/2021] [Indexed: 12/17/2022]
Abstract
The macroevolutionary transition from terra firma to obligatory inhabitance of the marine hydrosphere has occurred twice in the history of Mammalia: Cetacea and Sirenia. In the case of Cetacea (whales, dolphins, and porpoises), molecular phylogenies provide unambiguous evidence that fully aquatic cetaceans and semiaquatic hippopotamids (hippos) are each other's closest living relatives. Ancestral reconstructions suggest that some adaptations to the aquatic realm evolved in the common ancestor of Cetancodonta (Cetacea + Hippopotamidae). An alternative hypothesis is that these adaptations evolved independently in cetaceans and hippos. Here, we focus on the integumentary system and evaluate these hypotheses by integrating new histological data for cetaceans and hippos, the first genome-scale data for pygmy hippopotamus, and comprehensive genomic screens and molecular evolutionary analyses for protein-coding genes that have been inactivated in hippos and cetaceans. We identified eight skin-related genes that are inactivated in both cetaceans and hippos, including genes that are related to sebaceous glands, hair follicles, and epidermal differentiation. However, none of these genes exhibit inactivating mutations that are shared by cetaceans and hippos. Mean dates for the inactivation of skin genes in these two clades serve as proxies for phenotypic changes and suggest that hair reduction/loss, the loss of sebaceous glands, and changes to the keratinization program occurred ∼16 Ma earlier in cetaceans (∼46.5 Ma) than in hippos (∼30.5 Ma). These results, together with histological differences in the integument and prior analyses of oxygen isotopes from stem hippopotamids ("anthracotheres"), support the hypothesis that aquatic skin adaptations evolved independently in hippos and cetaceans.
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Affiliation(s)
- Mark S Springer
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA 92521, USA.
| | - Christian F Guerrero-Juarez
- Department of Mathematics, University of California, Irvine, Irvine, CA 92697, USA; NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, Irvine, CA 92697, USA; Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA; Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA 92697, USA
| | - Matthias Huelsmann
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany; Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany; Center for Systems Biology Dresden, 01307 Dresden, Germany
| | - Matthew A Collin
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA 92521, USA; Department of Botany & Plant Sciences, University of California, Riverside, Riverside, CA 92521, USA
| | - Kerri Danil
- Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla, CA 92037, USA
| | - Michael R McGowen
- Department of Vertebrate Zoology, Smithsonian Museum of Natural History, 10th & Constitution Avenue NW, Washington, DC 20560, USA
| | - Ji Won Oh
- Department of Anatomy, School of Medicine, Kyungpook National University, Daegu, Korea; Biomedical Research Institute, Kyungpook National University Hospital, Daegu, Korea; Hair Transplantation Center, Kyungpook National University Hospital, Daegu, Korea
| | - Raul Ramos
- NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, Irvine, CA 92697, USA; Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA; Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA 92697, USA
| | - Michael Hiller
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany; Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany; Center for Systems Biology Dresden, 01307 Dresden, Germany; LOEWE Centre for Translational Biodiversity Genomics, 60325 Frankfurt, Germany; Senckenberg Research Institute, 60325 Frankfurt, Germany; Faculty of Biosciences, Goethe-University, 60438 Frankfurt, Germany.
| | - Maksim V Plikus
- NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, Irvine, CA 92697, USA; Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA; Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA 92697, USA.
| | - John Gatesy
- Division of Vertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA.
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6
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The Endocranial Cast of Indohyus (Artiodactyla, Raoellidae): The Origin of the Cetacean Brain. J MAMM EVOL 2021. [DOI: 10.1007/s10914-021-09552-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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7
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Houssaye A, Martin F, Boisserie JR, Lihoreau F. Paleoecological Inferences from Long Bone Microanatomical Specializations in Hippopotamoidea (Mammalia, Artiodactyla). J MAMM EVOL 2021. [DOI: 10.1007/s10914-021-09536-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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8
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Cooper LN, Ball HC, Vinyard CJ, Safadi FF, George JC, Thewissen JGM. Linking gene expression and phenotypic changes in the developmental and evolutionary origins of osteosclerosis in the ribs of bowhead whales (Balaena mysticetus). JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2020; 334:339-349. [PMID: 32729176 DOI: 10.1002/jez.b.22990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/04/2020] [Accepted: 06/18/2020] [Indexed: 12/22/2022]
Abstract
Bowhead whales are among the longest-lived mammals with an extreme lifespan of about 211 years. During the first 25 years of their lives, rib bones increase in mineral density and the medulla transitions from compact to trabecular bone. Molecular drivers associated with these phenotypic changes in bone remain unknown. This study assessed expression levels of osteogenic genes from samples of rib bones of bowheads. Samples were harvested from prenatal to 86-year-old whales, representing the first third of the bowhead lifespan. Fetal to 2-year-old bowheads showed expression levels consistent with the rapid deposition of the bone extracellular matrix. Sexually mature animals showed expression levels associated with low rates of osteogenesis and increased osteoclastogenesis. After the first 25 years of life, declines in osteogenesis corresponded with increased expression of EZH2, an epigenetic regulator of osteogenesis. These findings suggest EZH2 may be at least one epigenetic modifier that contributes to the age-related changes in the rib bone phenotype along with the transition from compact to trabecular bone. Ancient cetaceans and their fossil relatives also display these phenotypes, suggesting EZH2 may have shaped the skeleton of whales in evolutionary history.
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Affiliation(s)
- Lisa N Cooper
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, USA.,Department of Anatomy and Neurobiology, Musculoskeletal Research Group, Northeast Ohio Medical University, Rootstown, Ohio, USA
| | - Hope C Ball
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, USA.,Department of Anatomy and Neurobiology, Musculoskeletal Research Group, Northeast Ohio Medical University, Rootstown, Ohio, USA
| | - Christopher J Vinyard
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, USA.,Department of Anatomy and Neurobiology, Musculoskeletal Research Group, Northeast Ohio Medical University, Rootstown, Ohio, USA
| | - Fayez F Safadi
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, USA.,Department of Anatomy and Neurobiology, Musculoskeletal Research Group, Northeast Ohio Medical University, Rootstown, Ohio, USA.,Department of Orthopedics, Rebecca D. Considine Research Institute, Akron Children's Hospital, Akron, Ohio, USA
| | - John C George
- Department of Wildlife Management, The North Slope Borough, Utqiagvik, Alaska, USA
| | - Johannes G M Thewissen
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, USA.,Department of Anatomy and Neurobiology, Musculoskeletal Research Group, Northeast Ohio Medical University, Rootstown, Ohio, USA
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9
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Sun D, Zhou X, Yu Z, Xu S, Seim I, Yang G. Accelerated evolution and diversifying selection drove the adaptation of cetacean bone microstructure. BMC Evol Biol 2019; 19:194. [PMID: 31651232 PMCID: PMC6813995 DOI: 10.1186/s12862-019-1509-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 09/05/2019] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND The transition from land to sea by the ancestor of cetaceans approximately 50 million years ago was an incredible evolutionary event that led to a series of morphological, physiological, and behavioral adaptations. During this transition, bone microstructure evolved from the typical terrestrial form to the specialized structure found in modern cetaceans. While the bone microstructure of mammals has been documented before, investigations of its genetic basis lag behind. The increasing number of cetaceans with whole-genome sequences available may shed light on the mechanism underlying bone microstructure evolution as a result of land to water transitions. RESULTS Cetacean bone microstructure is consistent with their diverse ecological behaviors. Molecular evolution was assessed by correlating bone microstructure and gene substitution rates in terrestrial and aquatic species, and by detecting genes under positive selection along ancestral branches of cetaceans. We found that: 1) Genes involved in osteoclast function are under accelerated evolution in cetaceans, suggestive of important roles in bone remodeling during the adaptation to an aquatic environment; 2) Genes in the Wnt pathway critical for bone development and homeostasis show evidence of divergent evolution in cetaceans; 3) Several genes encoding bone collagens are under selective pressure in cetaceans. CONCLUSIONS Our results suggest that evolutionary pressures have shaped the bone microstructure of cetaceans, to facilitate life in diverse aquatic environments.
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Affiliation(s)
- Di Sun
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023 China
| | - Xuming Zhou
- Key Laboratory of Animal Ecology and Conservation Biology, Chinese Academy of Sciences, Institute of Zoology, Beijing, China
| | - Zhenpeng Yu
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023 China
| | - Shixia Xu
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023 China
| | - Inge Seim
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing, 210023 China
- Comparative and Endocrine Biology Laboratory, Translational Research Institute-Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology, Brisbane, 4102 Australia
| | - Guang Yang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023 China
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Springer MS, Gatesy J. Evolution of the MC5R gene in placental mammals with evidence for its inactivation in multiple lineages that lack sebaceous glands. Mol Phylogenet Evol 2017; 120:364-374. [PMID: 29277542 DOI: 10.1016/j.ympev.2017.12.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/09/2017] [Indexed: 12/30/2022]
Abstract
MC5R is one of five melanocortin receptor genes found in placental mammals. MC5R plays an important role in energy homeostasis and is also expressed in the terminal differentiation of sebaceous glands. Among placental mammals there are multiple lineages that either lack or have degenerative sebaceous glands including Cetacea (whales, dolphins, and porpoises), Hippopotamidae (hippopotamuses), Sirenia (manatees and dugongs), Proboscidea (elephants), Rhinocerotidae (rhinos), and Heterocephalus glaber (naked mole rat). Given the loss or diminution of sebaceous glands in these taxa, we procured MC5R sequences from publicly available genomes and transcriptomes, supplemented by a newly generated sequence for Choeropsis liberiensis (pygmy hippopotamus), to determine if this gene remains intact or is inactivated in association with loss/reduction of sebaceous glands. Our data set includes complete MC5R sequences for 114 placental mammal species including two individuals of Mammuthus primigenius (woolly mammoth) from Oimyakon and Wrangel Island. Complete loss or inactivation of the MC5R gene occurs in multiple placental lineages that have lost sebaceous glands (Cetacea, West Indian manatee, African elephant, white rhinoceros) or are characterized by unusual skin (pangolins, aardvarks). Both M. primigenius individuals share inactivating mutations with the African elephant even though sebaceous glands have been reported in the former. MC5R remains intact in hippopotamuses and the naked mole rat, although slightly elevated dN/dS ratios in these lineages allow for the possibility that the accumulation of inactivating mutations in MC5R may lag behind the relaxation of purifying selection. For Cetacea and Hippopotamidae, the absence of shared inactivating mutations in two different skin genes (MC5R, PSORS1C2) is consistent with the hypothesis that semi-aquatic lifestyles were acquired independently in these clades following divergence from a common ancestor.
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Affiliation(s)
- Mark S Springer
- 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.
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11
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Houssaye A, Fish FE. Functional (Secondary) Adaptation to an Aquatic Life in Vertebrates: An Introduction to the Symposium. Integr Comp Biol 2016; 56:1266-1270. [DOI: 10.1093/icb/icw129] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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