DOCSLIB.ORG

Axolotl Paedomorphosis: a Comparison of Juvenile, Metamorphic, and Paedomorphic Ambystoma Mexicanum Brain Gene Transcription

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Axolotl Paedomorphosis: a Comparison of Juvenile, Metamorphic, and Paedomorphic Ambystoma Mexicanum Brain Gene Transcription University of Kentucky UKnowledge Theses and Dissertations--Biology Biology 2013 AXOLOTL PAEDOMORPHOSIS: A COMPARISON OF JUVENILE, METAMORPHIC, AND PAEDOMORPHIC AMBYSTOMA MEXICANUM BRAIN GENE TRANSCRIPTION Carlena Johnson [email protected] Right click to open a feedback form in a new tab to let us know how this document benefits ou.y Recommended Citation Johnson, Carlena, "AXOLOTL PAEDOMORPHOSIS: A COMPARISON OF JUVENILE, METAMORPHIC, AND PAEDOMORPHIC AMBYSTOMA MEXICANUM BRAIN GENE TRANSCRIPTION" (2013). Theses and Dissertations--Biology. 13. https://uknowledge.uky.edu/biology_etds/13 This Master's Thesis is brought to you for free and open access by the Biology at UKnowledge. It has been accepted for inclusion in Theses and Dissertations--Biology by an authorized administrator of UKnowledge. For more information, please contact [email protected]. STUDENT AGREEMENT: I represent that my thesis or dissertation and abstract are my original work. Proper attribution has been given to all outside sources. I understand that I am solely responsible for obtaining any needed copyright permissions. I have obtained and attached hereto needed written permission statements(s) from the owner(s) of each third-party copyrighted matter to be included in my work, allowing electronic distribution (if such use is not permitted by the fair use doctrine). I hereby grant to The University of Kentucky and its agents the non-exclusive license to archive and make accessible my work in whole or in part in all forms of media, now or hereafter known. I agree that the document mentioned above may be made available immediately for worldwide access unless a preapproved embargo applies. I retain all other ownership rights to the copyright of my work. I also retain the right to use in future works (such as articles or books) all or part of my work. I understand that I am free to register the copyright to my work. REVIEW, APPROVAL AND ACCEPTANCE The document mentioned above has been reviewed and accepted by the student’s advisor, on behalf of the advisory committee, and by the Director of Graduate Studies (DGS), on behalf of the program; we verify that this is the final, approved version of the student’s dissertation including all changes required by the advisory committee. The undersigned agree to abide by the statements above. Carlena Johnson, Student Dr. S. Randal Voss, Major Professor Dr. Brian Rymond, Director of Graduate Studies AXOLOTL PAEDOMORPHOSIS: A COMPARISON OF JUVENILE, METAMORPHIC, AND PAEDOMORPHIC AMBYSTOMA MEXICANUM BRAIN GENE TRANSCRIPTION ____________________________________ THESIS ____________________________________ A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in the College of Arts and Sciences at the University of Kentucky By Carlena K. Johnson Lexington, Kentucky Director: Dr. S. Randal Voss, Professor of Biology Lexington, Kentucky 2013 Copyright © Carlena K. Johnson 2013 ABSTRACT OF THESIS AXOLOTL PAEDOMORPHOSIS: A COMPARISON OF JUVENILE, METAMORPHIC, AND PAEDOMORPHIC AMBYSTOMA MEXICANUM BRAIN GENE TRANSCRIPTION Unlike many amphibians, the paedomorphic axolotl (Ambystoma mexicanum) rarely undergoes external morphological changes indicative of metamorphosis. However, internally, some axolotl tissues undergo cryptic metamorphic changes. A previous study examined interspecific patterns of larval brain gene expression and found that these species exhibited unique temporal expression patterns that were hypothesized to be morph specific. This thesis tested this hypothesis by examining differences in brain gene expression between juvenile (JUV), paedomorphic (PAED), and metamorphic (MET) axolotls. I identified 828 genes that were expressed differently between JUV, PAED, and MET. Expression estimates from JUV were compared to estimates from PAED and MET brains to identify genes that changed significantly during development. Genes that showed statistically equivalent expression changes across MET and PAED brains provide a glimpse at aging and maturation in an amphibian. The genes that showed statistically different expression estimates between metamorphic and paedomorphic brains provide new functional insights into the maintenance and regulation of paedomorphosis. For genes that were not commonly regulated due to aging, paedomorphs exhibited greater transcriptional similarity to juvenile than metamorphs did to juvenile. Overall, gene expression differences between metamorphic and paedomorphic development exhibit a mosaic pattern of expression as a function of aging and metamorphosis in axolotls. KEYWORDS: Ambystoma; metamorphosis; paedomorphosis; microarray; gene expression Carlena K. Johnson (July 1, 2013) AXOLOTL PAEDOMORPHOSIS: A COMPARISON OF JUVENILE, METAMORPHIC AND PAEDOMORPHIC AMBYSTOMA MEXICANUM BRAIN GENE TRANSCRIPTION By Carlena K. Johnson DR. S. RANDAL VOSS DIRECTOR OF THESIS DR. DAVID WESTNEAT DIRECTOR OF GRADUATE STUDIES (JULY 1, 2013) ACKNOWLEDGEMENTS I thank the many people who have helped me with this project. I expressly thank Randal Voss for all of his time and patience in teaching me about genomics and the writing process. I am immensely grateful for your help and assistance during this project. I thank Antony Athippozhy for his assistance and guidance on how to manipulate and analyze microarray data. I also thank all the members of the Voss lab, especially, John Walker, Kevin Kump, Sri Putta, and Tyler Frye for their support and encouragement. I thank my committee members, Jeramiah Smith and Vinnie Cassone for their support in this project. Thank you to the faculty and staff of the Biology Department. This project was supported through grants received by Randal Voss from NSF and NIH. I would like to thank my friends and family for their unwavering support through this project. Thank you to my mom and fiancé, Tom, for their encouragement and reassurance. iii TABLE OF CONTENTS Acknowledgements.…………………………………………………………………… iii List of Tables.………………………………………………………………………….. vi List of Figures.………………………………………………………………………… vii Chapter One: Literature Review.……………………………………………………….. 1 Why paedomorphosis and why salamanders?………………………………..… 1 Paedomorphosis and salamander life history variation…….…………………... 4 Hormonal basis of salamander metamorphosis………………………..……….. 6 Hormonal basis of paedomorphosis……………………………….……..…..… 8 Paedomorphosis in the Mexican Axolotl……………………….…….….…… 11 Transcriptional analysis of salamander metamorphosis and paedomorphosis.………………………………………………………….. 13 Genetic analysis of paedomorphosis………………………………….….….... 15 The link between met1 and thyroid hormone regulation of metamorphosis…………………………………………………………...… 17 What genes map to metamorphic timing QTL?………………………….…… 18 Synthesis: evolution of salamander paedomorphosis……………………..…... 19 Chapter Two: Microarray comparison of juvenile, paedomorphic and metamorphic brain gene transcription……………………………..…….... 28 Introduction ………………………………………………………………....… 28 Methods……………………………………………………………..…………. 29 Animals and tissue sampling…………………………………...…….... 29 RNA isolation and microarray analysis………………………...…….... 29 Global analyses of microarray data……………………………...…….. 30 Identification of differently expressed genes (DEGs) using microarray……………………………………………………….. 30 Identification of statistically enriched biological processes………....… 30 Bioinformatic validation of morph specific gene expression……...…... 31 iv Results ………………………………………………………………………….. 31 Global analysis of gene expression……………………………………... 31 Identification of differently expressed genes among juvenile and adult brains………………………………………….…..… 32 Classification of adult gene expression patterns relative to juvenile…… 32 Identification of statistically enriched biological processes………….… 33 Bioinformatic analysis of morph specific gene expression ……………………………………………………….... 35 Discussion………………………………………………………………………. 36 Aging and transcription in the A. mexicanum brain………………….…. 37 Genes associated with metamorphosis and paedomorphosis…………… 39 Aging, species, and morph specific differences in hemoglobin expression…………………………………………………. 43 References…………………………………………………………………………...…. 61 v LIST OF TABLES Table 1.1, General characteristics of salamander life history………………………..… 22 Table 2.1, List of genes that show greater than three standard deviations from predicted values………….………………………..……………….…. 46 Table 2.2, List of over-represented ontology terms………………………….………… 47 Table 2.3, Pattern of gene expression comparison with DEGs from Page et al. (2010)……………………………………………………………….… 51 vi LIST OF FIGURES Figure 1.1, Representative salamander larva, adult metamorph (Ambystoma tigrinum) and adult paedomorph (A. mexicanum)……………………………………………...… 23 Figure 1.2, Timeline showing timing of fore and hindlimb development and the metamorphic period of laboratory reared A. t. tigrinum………………………. 24 Figure 1.3, Photo of Ambystoma dumerilii……………………………………………. 25 Figure 1.4, Gene expression profiles……………………...…………………………... 26 Figure 1.5, Model showing relationships among salamander life history variation, physiology, and habitat stability…………………………………...……….. 27 Figure 2.1, Box plots of GeneChips……………………….………………………....... 54 Figure 2.2, Principle components analysis………………….……………………….… 55 Figure 2.3, Hierarchical clustering analysis………………………………….………... 56 Figure 2.4, Venn diagram of significant DEGs…………………………..……………. 57 Figure 2.5, Patterns of gene expression change for PAED and MET relative to JUV..……………………………………………………………………….. 58 Figure 2.6, Bivariate plot of PAED and MET expression
Load more

Recommended publications
  • Identification of Mutant Genes and Introgressed Tiger Salamander
    www.nature.com/scientificreports OPEN Identification of Mutant Genes and Introgressed Tiger Salamander DNA in the Laboratory Axolotl, Received: 13 October 2016 Accepted: 19 December 2016 Ambystoma mexicanum Published: xx xx xxxx M. Ryan Woodcock1, Jennifer Vaughn-Wolfe1, Alexandra Elias2, D. Kevin Kump1, Katharina Denise Kendall1,5, Nataliya Timoshevskaya1, Vladimir Timoshevskiy1, Dustin W. Perry3, Jeramiah J. Smith1, Jessica E. Spiewak4, David M. Parichy4,6 & S. Randal Voss1 The molecular genetic toolkit of the Mexican axolotl, a classic model organism, has matured to the point where it is now possible to identify genes for mutant phenotypes. We used a positional cloning– candidate gene approach to identify molecular bases for two historic axolotl pigment phenotypes: white and albino. White (d/d) mutants have defects in pigment cell morphogenesis and differentiation, whereas albino (a/a) mutants lack melanin. We identified in white mutants a transcriptional defect in endothelin 3 (edn3), encoding a peptide factor that promotes pigment cell migration and differentiation in other vertebrates. Transgenic restoration of Edn3 expression rescued the homozygous white mutant phenotype. We mapped the albino locus to tyrosinase (tyr) and identified polymorphisms shared between the albino allele (tyra) and tyr alleles in a Minnesota population of tiger salamanders from which the albino trait was introgressed. tyra has a 142 bp deletion and similar engineered alleles recapitulated the albino phenotype. Finally, we show that historical introgression of tyra significantly altered genomic composition of the laboratory axolotl, yielding a distinct, hybrid strain of ambystomatid salamander. Our results demonstrate the feasibility of identifying genes for traits in the laboratory Mexican axolotl. The Mexican axolotl (Ambystoma mexicanum) is the primary salamander model in biological research.
    [Show full text]
  • The Origins of Chordate Larvae Donald I Williamson* Marine Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
    lopmen ve ta e l B Williamson, Cell Dev Biol 2012, 1:1 D io & l l o l g DOI: 10.4172/2168-9296.1000101 e y C Cell & Developmental Biology ISSN: 2168-9296 Research Article Open Access The Origins of Chordate Larvae Donald I Williamson* Marine Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom Abstract The larval transfer hypothesis states that larvae originated as adults in other taxa and their genomes were transferred by hybridization. It contests the view that larvae and corresponding adults evolved from common ancestors. The present paper reviews the life histories of chordates, and it interprets them in terms of the larval transfer hypothesis. It is the first paper to apply the hypothesis to craniates. I claim that the larvae of tunicates were acquired from adult larvaceans, the larvae of lampreys from adult cephalochordates, the larvae of lungfishes from adult craniate tadpoles, and the larvae of ray-finned fishes from other ray-finned fishes in different families. The occurrence of larvae in some fishes and their absence in others is correlated with reproductive behavior. Adult amphibians evolved from adult fishes, but larval amphibians did not evolve from either adult or larval fishes. I submit that [1] early amphibians had no larvae and that several families of urodeles and one subfamily of anurans have retained direct development, [2] the tadpole larvae of anurans and urodeles were acquired separately from different Mesozoic adult tadpoles, and [3] the post-tadpole larvae of salamanders were acquired from adults of other urodeles. Reptiles, birds and mammals probably evolved from amphibians that never acquired larvae.
    [Show full text]
  • Axolotl Care Compiled by Dayna Willems, DVM
    Axolotl Care Compiled by Dayna Willems, DVM Brief Description Axolotls (Ambystoma mexicanum) are a Mexican species of aquatic salamander that has rapidly come into the pet trade due to their hardy nature and unusual appearance. Axolotls are amphibians meaning that they do go through several stages of metamorphosis before reaching their adult form. Axolotls are unusual in that their adult/reproductive stage is the same as the juvenile aquatic stage. This is called neoteny and is often considered a “backward” step in evolution. Axolotls are closely related to Tiger Salamanders which do eventually morph into a terrestrial form. It should be noted that under extreme stress, an axolotl may morph into a terrestrial form, but their life is significantly shortened. Being amphibians, axolotls do not tolerate handling well and must stay in the water to breathe. They have sensitive skin and can absorb toxins from the water or your skin. Should you need to transport your axolotl or move it for tank maintenance, do not use a net. Nets can cause abrasions in your axolotl’s sensitive skin or damage the gills. Instead use a plastic cup to scoop your axolotl out of the enclosure. Lifespan Providing the correct care to your axolotl will ensure a long life. Average life expectancy is around 10 years, but reports have been found of axolotls living into their 20’s. Their adult size is around 10 to 12 inches; which they typically reach within the first year of their life. Sexing Axolotls reach sexual maturity when they are around 6-8 inches long.
    [Show full text]
  • Calotriton Asper)
    Amphibia-Reptilia (2014) DOI:10.1163/15685381-00002921 Life history trait differences between a lake and a stream-dwelling population of the Pyrenean brook newt (Calotriton asper) Neus Oromi1,∗, Fèlix Amat2, Delfi Sanuy1, Salvador Carranza3 Abstract. The Pyrenean brook newt (Calotriton asper) is a salamandrid that mostly lives in fast running and cold mountain- streams, although some populations are also found in lakes. In the present work, we report in detail on the occurrence of facultative paedomorphosis traits in a population from a Pyrenean high altitude lake. We compare its morphology, life history traits and mitochondrial DNA variation with a nearby lotic metamorphic population. Our results indicate that the lacustrine newts are smaller and present a less developed sexual dimorphism, smooth skin, and that 53% of the adults retain gills at different degrees of development, but not gill slits. Although both populations and sexes have the same age at sexual maturity (four years), the lacustrine population presents higher longevity (12 and 9 years for males and females, respectively) than the one living in the stream (8 and 9 years). The variation on the climatic conditions at altitudinal scale is probably the main cause of the differences in life history traits found between the two populations. The food availability, which could to be limiting in the lacustrine population, is another factor that can potentially affect body size. These results are congruent with the significant mitochondrial DNA genetic isolation between populations, probably a consequence of the lack of juvenile dispersal. We found low cytochrome b variability and significant genetic structuring in the lake population that is very remarkably considering the short distance to the nearby stream population and the whole species’ pattern.
    [Show full text]
  • FROGLOG Newsletter of the IUCN /SSC Amphibian Specialist Group (ASG)
    Ambystoma opacum byTim Halliday ISSN 1026-0269 FROGLOG Newsletter of the IUCN /SSC Amphibian Specialist Group (ASG) December 2006, Number 78 amphibian species entering ponds individuals. Computer assisted Impacts of from clearcut versus forest habitats pattern-matching software clearcutting on across years. Of the 149,756 developed specifically for A. amphibians amphibians that were captured opacum by Lex Hiby of after 20 years and included in our analysis, 17 of Conservation Research Ltd. of forest re- 18 species at all ponds in all years (Cambridge, UK) drastically establishment migrated to ponds in significantly reduced the number of photo By: Don R. Church, Henry M. smaller numbers from the clearcut comparisons that needed to be Wilbur and Larissa Bailey habitats than from the forest made by eye. Individuals had habitats associated with each overall high fidelity to their point of The long-term impacts of forestry pond. The one exception was the entry to and exit from a pond within practices on amphibian spring peeper, Hyla crucifer, which and across years. populations remain uncertain. was caught in significantly larger Using recently developed multi- Several studies in eastern North numbers entering from the clearcut state mark-recapture methods America have previously shown habitat at each pond. These (Bailey et al., 2004) and that clearcutting of upland forests results raised the question: Why multimodel inference (Burnham & results in a reduction in the number exactly do fewer amphibians Anderson, 2002) we found that of pond-breeding amphibians that migrate to ponds from clearcut survival probabilities within both migrate to breeding sites. habitats after 20 years of forest breeding and non-breeding However, in general, deciduous reestablishment? The answer to seasons varied among years, forests of eastern North America this question has important populations, and between habitats.
    [Show full text]
  • Hearing Sensitivity and the Effect of Sound Exposure on the Axolotl (Ambystoma Mexicanum) Amy K
    Western Kentucky University TopSCHOLAR® Masters Theses & Specialist Projects Graduate School 5-2015 Hearing Sensitivity and the Effect of Sound Exposure on the Axolotl (Ambystoma Mexicanum) Amy K. Fehrenbach Western Kentucky University, [email protected] Follow this and additional works at: http://digitalcommons.wku.edu/theses Part of the Biology Commons, and the Cell and Developmental Biology Commons Recommended Citation Fehrenbach, Amy K., "Hearing Sensitivity and the Effect of Sound Exposure on the Axolotl (Ambystoma Mexicanum)" (2015). Masters Theses & Specialist Projects. Paper 1496. http://digitalcommons.wku.edu/theses/1496 This Thesis is brought to you for free and open access by TopSCHOLAR®. It has been accepted for inclusion in Masters Theses & Specialist Projects by an authorized administrator of TopSCHOLAR®. For more information, please contact [email protected]. HEARING SENSITIVITY AND THE EFFECT OF SOUND EXPOSURE ON THE AXOLOTL (AMBYSTOMA MEXICANUM) A Thesis Presented to The Faculty of the Department of Biology Western Kentucky University Bowling Green, Kentucky In Partial Fulfillment Of the Requirements for the Degree Master of Science By Amy K Fehrenbach May 2015 2 I dedicate this thesis to my parents, Paul and Debbie Fehrenbach. Your love and support have made all of this possible, and I could not have done it without you. Thank you for everything. ACKNOWLEDGMENTS I would first like to thank Dr. Michael Smith for mentoring and advising me throughout my time at WKU. His guidance, work ethic, and positive attitude have made this project possible. I would also like to thank my committee members Dr. Steve Huskey and Dr. Wieb van der Meer for their feedback and patience during this process.
    [Show full text]
  • Invited Review the Phylogenetic Odyssey of the Erythrocyte. IV. The
    Histol Histopathol (1997) 12: 147-170 Histology and 001: 10.14670/HH-12.147 Histopathology http://www.hh.um.es From Cell Biology to Tissue Engineering Invited Review The phylogenetic odyssey of the erythrocyte. IV. The amphibians C.A. Glomski, J. Tamburlin, R. Hard and M. Chainani State University of New York at Buffalo, Department of Anatomy and Cell Biology, School of Medicine, Buffalo, New York, USA Summary. Amphibians mani fes t permanently nucleated , Introduction oval. flatte ned , biconvex ery throcytes. These cell s demonstrate a cytoskeleton which is responsible for their H e moglo bin is a n unique, a nc ie nt respirato ry morphogeneti c conversion from a sphere to an ellipse me ta ll o -pig m e nt w hose s pec ia li zed func ti o ns a nd imparts to the ir cellular m ass revers ibility of a re d e mo ns tra bly e nha nced by it s m ic ro ­ traumati c deformati o n. The class Amphibia has the environmentali zati on in a passive-flowi ng, circulating largest of all erythrocytes attaining volumes greater than cell as opposed to free physical solution in the plasma as 10,000 fe mto lite rs in the Amphiuma. The la rge seen at the in vertebrate level (Glomski and Tamburlin, dimensions re fl ect evolutionary processes, genomic size, 1989). The degree of its polymeri zati on, association with plo id y a nd the re lative size of o the r somati c cell s. interactive enzyme syste ms, and the structure o f it s Conversely, the ery throcyte count a nd he mog lobin globin chains confe r upon the compound a spectrum of concentrat io n of these spec ies are low.
    [Show full text]
  • 50 CFR Ch. I (10–1–20 Edition) § 16.14
    § 15.41 50 CFR Ch. I (10–1–20 Edition) Species Common name Serinus canaria ............................................................. Common Canary. 1 Note: Permits are still required for this species under part 17 of this chapter. (b) Non-captive-bred species. The list 16.14 Importation of live or dead amphib- in this paragraph includes species of ians or their eggs. non-captive-bred exotic birds and coun- 16.15 Importation of live reptiles or their tries for which importation into the eggs. United States is not prohibited by sec- Subpart C—Permits tion 15.11. The species are grouped tax- onomically by order, and may only be 16.22 Injurious wildlife permits. imported from the approved country, except as provided under a permit Subpart D—Additional Exemptions issued pursuant to subpart C of this 16.32 Importation by Federal agencies. part. 16.33 Importation of natural-history speci- [59 FR 62262, Dec. 2, 1994, as amended at 61 mens. FR 2093, Jan. 24, 1996; 82 FR 16540, Apr. 5, AUTHORITY: 18 U.S.C. 42. 2017] SOURCE: 39 FR 1169, Jan. 4, 1974, unless oth- erwise noted. Subpart E—Qualifying Facilities Breeding Exotic Birds in Captivity Subpart A—Introduction § 15.41 Criteria for including facilities as qualifying for imports. [Re- § 16.1 Purpose of regulations. served] The regulations contained in this part implement the Lacey Act (18 § 15.42 List of foreign qualifying breed- U.S.C. 42). ing facilities. [Reserved] § 16.2 Scope of regulations. Subpart F—List of Prohibited Spe- The provisions of this part are in ad- cies Not Listed in the Appen- dition to, and are not in lieu of, other dices to the Convention regulations of this subchapter B which may require a permit or prescribe addi- § 15.51 Criteria for including species tional restrictions or conditions for the and countries in the prohibited list.
    [Show full text]
  • First Report of Melanism in the Salamander Bolitoglossa Rufescens (Caudata: Plethodontidae) in Veracruz, México
    Nota Cuad. herpetol. 34(1): 99-101 (2020) First report of melanism in the salamander Bolitoglossa rufescens (Caudata: Plethodontidae) in Veracruz, México Víctor Vásquez-Cruz1, Axel Fuentes-Moreno2, Monserrath Campos-Cerón3 1 PIMVS Herpetario Palancoatl, Avenida 19 número 5525, Colonia Nueva Esperanza, C.P. 94540, Córdoba, Veracruz, México. 2 Colegio de Postgraduados, Campus Montecillo. Carretera México-Texcoco km 36.5, Montecillo, C.P. 56230, Texcoco, Estado de México, México. 3 Escuela Secundaria General No. 2, Vía Muerta S/N, Colonia El Morro, C.P. 94293, Boca del Río, Veracruz, México. Recibida: 13 Noviembre 2019 ABSTRACT Revisada: 20 Enero 2020 Several cases of pigmentary abnormalities have been documented in salamanders. These ab- Aceptada: 21 Enero 2020 normalities can be partial or total and are derived from the absence or excess of pigmentation Editor Asociado: C. Borteiro produced by chromatophores (pigment cells). Here, we present the first record of melanism in the salamander Bolitoglossa rufescens, from Veracruz, Mexico, being this the second case of abnormal pigmentation in the genus Bolitoglossa. doi: 10.31017/CdH.2020.(2019-048) Key Words: Amphibians, Chromatophores, Pigmentary abnormalities. The color we perceive from animals is influenced or melanism (dominance of melanophores; e.g. by the spatial distribution of chromatophores (pig- Bolitoglossa tenebrosa, Isthmura corrugata), there ment cells), the amount and type of pigment they are a limited number of cases of aberrant melanism contain, as well as the reflection of light on them (when the pigmented cells are more abundant than (Rivera et al., 2001). There are different pigment in normal individuals) reported in these amphibians, cells: melanophores (black-brown), xanthophores for example in Salamandra salamandra, Triturus (yellow), cyanophores (blue), erythrophores (red), marmoratus, Calotriton asper, Euproctus montanus, and leukophores (white) (Fernández Guiberteau et Lissotriton boscai, Speleomantes imperialis and S.
    [Show full text]
  • Discoglossus Sardus and Euproctus Montanus During the Breeding Season
    HERPETOLOGICAL JOURNAL, Vol. 9, pp. 163-167 (1999) FEEDING HABITS OF SYMPATRIC DJSCOGLOSSUS MONTALENTII, DISCOGLOSSUS SARDUS AND EUPROCTUS MONTANUS DURING THE BREEDING SEASON SEBASTIANO SALYIDI01 , ROBERTO SINDAC02 AND LlVIO EMANUELl3 'Istituto di Zoologia, Universita di Genova, Via Balbi 5, I- I6126 Genova, Italy 2Istituto per le Piante da Legno e Ambiente, Corso Casale 476, 1- 10I 32 Torino, Italy 1Acquario di Genova, Area Porto Antico - Ponte Sp inola, I- 16128 Genova Italy The diets of three Corsican amphibians, Discoglossus montalentii, Discoglossus sardus and Euproctus montanus, were studied in the Ospedale region during the breeding season. Adult specimens were collected in or around breeding pools and were stomach flushed in the field. Prey taxa included a large variety of terrestrial and aquatic prey items of variable size, indicating opportunistic predation. All species were able to catch their prey both on land and in water, but varied in the proportions of aquatic and terrestrial prey consumed. E. montanus fed largely upon benthic macroinvertebrates, suggesting predation in deep water; D. sardus mainly captured terrestrial prey; and D. montalentii showed a mixed fe eding strategy, preying upon both terrestrial and aquatic prey categories in similar proportions. Discoglossus sardus showed the highest standardized value of niche breadth (D, = 0. 769), compared to D. montalentii and E. montanus (D, = 0.544 and D, = 0.523 respectively). When prey size frequency distributions were compared, no specific differences were observed. These results indicated that, at least during the breeding season, trophic segregation among sympatric amphibians was maintained by different foraging strategies, and that the three species exploited contiguous microhabitats in different ways.
    [Show full text]
  • The Axolotl Genome and the Evolution of Key Tissue Formation Regulators Sergej Nowoshilow1,2,3†*, Siegfried Schloissnig4*, Ji-Feng Fei5*, Andreas Dahl3,6, Andy W
    OPEN ArtICLE doi:10.1038/nature25458 The axolotl genome and the evolution of key tissue formation regulators Sergej Nowoshilow1,2,3†*, Siegfried Schloissnig4*, Ji-Feng Fei5*, Andreas Dahl3,6, Andy W. C. Pang7, Martin Pippel4, Sylke Winkler1, Alex R. Hastie7, George Young8, Juliana G. Roscito1,9,10, Francisco Falcon11, Dunja Knapp3, Sean Powell4, Alfredo Cruz11, Han Cao7, Bianca Habermann12, Michael Hiller1,9,10, Elly M. Tanaka1,2,3† & Eugene W. Myers1,10 Salamanders serve as important tetrapod models for developmental, regeneration and evolutionary studies. An extensive molecular toolkit makes the Mexican axolotl (Ambystoma mexicanum) a key representative salamander for molecular investigations. Here we report the sequencing and assembly of the 32-gigabase-pair axolotl genome using an approach that combined long-read sequencing, optical mapping and development of a new genome assembler (MARVEL). We observed a size expansion of introns and intergenic regions, largely attributable to multiplication of long terminal repeat retroelements. We provide evidence that intron size in developmental genes is under constraint and that species-restricted genes may contribute to limb regeneration. The axolotl genome assembly does not contain the essential developmental gene Pax3. However, mutation of the axolotl Pax3 paralogue Pax7 resulted in an axolotl phenotype that was similar to those seen in Pax3−/− and Pax7−/− mutant mice. The axolotl genome provides a rich biological resource for developmental and evolutionary studies. Salamanders boast an illustrious history in biological research as the 14.2 kb) using Pacific Biosciences (PacBio) instruments (Supplementary animal in which the Spemann organizer1 and Sperry’s chemoaffinity Information section 1) to avoid the read sampling bias that is often found theory of axonal guidance2 were discovered.
    [Show full text]
  • Exotic Animal Ownership and Regulations Amending New Jersey Species Restriction, Bans, and Requirements
    Exotic Animal Ownership and Regulations Amending New Jersey Species Restriction, Bans, and Requirements Tag Words: exotic animals; ownership Authors: Chris Dipiazza, Julie Haas with Julie M. Fagan, Ph.D. Summary The purpose of this whole project was to attempt to make a difference or at least get a better understanding of the issues surrounding the banning of owning certain kinds of exotic pets. Julie’s original concern went back to her not being able to transport her pet bird and lizard, Bearded Dragon, under her seat with her on a plane. Instead the airline insisted they be kept in storage beneath which can be extremely stressful especially for the bird, which is an African Gray Parrot, a species known for being extremely intelligent but also at the same time, very sensitive. My (Chris) issue had more to do with private responsible owners not being legally allowed to own certain species that really have no obvious reason for being unfit pets in the state of New Jersey. The species I was particularly focused on were salamanders belonging to the genus, amystoma. Their common names are the Tiger Salamander and the Axolotl. The first action we took to gain more information about transportation regulations and ownership regulations was to make a trip over to Hamburg, Pennsylvania to attend a reptile show, http://www.hamburgreptileshow.com/ , which is held there every other month. Reptile shows are gatherings for pet reptile enthusiasts to congregate, buy, trade, sell or just observe captive reptiles and other exotic pets. An educational seminar was also given on exotic animals, their ownership requirements, and their regulations.
    [Show full text]