DOCSLIB.ORG

Genetic Linkage and Color Polymorphism in the Southern Platyfish (Xiphophorus Maculatus): a Model System for Studies of Color Pattern Evolution

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Genetic Linkage and Color Polymorphism in the Southern Platyfish (Xiphophorus Maculatus): a Model System for Studies of Color Pattern Evolution ZEBRAFISH Volume 3, Number 1, 2006 © Mary Ann Liebert, Inc. Genetic Linkage and Color Polymorphism in the Southern Platyfish (Xiphophorus maculatus): A Model System for Studies of Color Pattern Evolution ALEXANDRA L. BASOLO ABSTRACT Color pattern polymorphisms are widespread in animals, and are found within populations, among populations, and among species. The southern platyfish, Xiphophorus maculatus, represents one of the most extreme examples of color pattern polymorphism. Extensive research with this model system for melanoma formation has resulted in an understanding of the underlying genetic basis of over 40 sex-linked and autosomal color patterns, includ- ing alleles that code for melanin, pterin, and carotenoid coloration. Research has also found that genes that affect sex determination, timing of sexual maturation, and coloration are genetically linked on the sex chromosomes. In many animals, color patterns often show strong sexual dimorphism, with conspicuous coloration limited to males. Although some of the color pattern alleles are sex-limited in platyfish, many are expressed by both sexes. Despite the abundance of work on this model system, little is known about the evolutionary processes responsible for this diversity of color pattern alleles. This review discusses what is known about platyfish coloration, and the roles that genetic linkage and variation in environmental conditions within and among populations might play in the evolution and maintenance of the extreme color pattern polymorphism exhibited by this platyfish. INTRODUCTION have favored the evolution of black vertical bars in males of the high-backed pygmy sword- XTENSIVE COLOR PATTERN DIVERSITY exists in tail, X. multilineatus.5 Ethe animal world, with variation both within Traits that increase an individual’s attrac- and among species. Such diversity likely has tiveness to the opposite sex may also increase adaptive significance. Coloration can be im- its conspicuousness to predators.6–8 Therefore, portant in reducing danger, with prey using whereas sexual selection is predicted to favor coloration to either warn predators or remain the evolution of more conspicuous coloration, cryptic to predators.1 Cryptic coloration can natural selection via predation should often fa- also be important to predators, reducing the vor the evolution of less conspicuous col- likelihood of their detection by potential prey. oration. Conspicuous red and orange col- Coloration is also known to play a role in both oration has been found to be attractive to mate choice and intrasexual competition.2 For females in a number of animals, including a va- example, mating preferences in one sex for riety of fishes, for example guppies, stickle- traits in the other sex appear to have favored backs, and swordtails.9–11 In the guppy, Poecilia the evolution of the colorful male sword in reticulata, females prefer males with larger or- green swordtails, Xiphophorus helleri.3,4 Intra- ange spot coloration.9 However, Endler7 found sexual competition, primarily competition that orange spots in guppies were smaller in among males for access to females, appears to populations with a high predation risk relative School of Biological Sciences, University of Nebraska—Lincoln, Lincoln, Nebraska. 65 66 BASOLO to populations with a low predation risk. Thus, the background; if there is a good match be- natural and sexual selection have opposing ef- tween an individual’s color pattern and the fects on the evolution of coloration in guppies; background color pattern, there will be a re- female mate choice favors orange or red spots duced likelihood of detection,7 especially at while predation disfavors these spots. In the greater distances. same study, the size of black, blue, iridescent, In addition to environmental effects on color and other colored spots also decreased when pattern conspicuousness, animals may modu- predation risk was increased. This suggests late the conspicuousness of color patterns us- that not only is red coloration conspicuous to ing a variety of behavioral mechanisms, such predators, but some black and iridescent color as expressing coloration on body sections that patterns are as well. In green swordtails, X. hel- can be facultatively hidden, using other indi- leri, natural and sexual selection appear to act viduals as a buffer between self and potential in opposition on the sword, a colorful male predators, and restricting activities to periods trait. While female green swordtails prefer when potential predators are least active. For long, multicolored swords,3,12 males from pop- example, some reef fishes limit their activities ulations with predatory fish have shorter during crepuscular hours (dawn and dusk) swords than males from populations in which when predation risk is relatively higher,14 and the predators are absent.8 guppies from high predation risk populations The conspicuousness of a color pattern, tend to school more than guppies from low pre- whether to a conspecific or a predator, can be dation populations.15 affected by environmental factors, such as am- Finally, the arrangement of color patterns on bient light conditions. For example, although the body can affect the conspicuousness of female sticklebacks, Gasterosteus aculeatus, pre- color patterns; reds or yellows contrasted ferred red males when the light environment against black can be particularly conspicuous.1 allowed the detection of red coloration, when For any given population, then, the optimal a filter blocked the transmission of red col- color pattern phenotypes are a balance between oration, females no longer exhibited the pref- different sources of selection, with the local bi- erence.10 In the green swordtail, X. helleri, fe- otic and abiotic environment playing an im- males prefer orange swords to green swords, portant role. The local environment, therefore, but when the light environment is experimen- should be highly predictive of the color pattern tally manipulated to reduce reflectance in the variation in a population residing there. When orange wavelengths, the preference is no environmental conditions are similar across a longer detected in prep.11 Likewise, in the species’ range, color patterns may also be sim- guppy, when wavelengths that reflect orange ilar. When environmental conditions are dis- are blocked, females no longer exhibit a pref- similar across a species’ range, color patterns erence for males with higher degrees of orange may be very different across populations. expression.13 In an aquatic environment, vari- Of the diverse types of coloration expressed ation in the spectral transmission of the water by animals, this review is primarily concerned stemming from differences in color and opac- with chromatophores found in the dermis, ity may also affect the perception of color pat- scales, integument, and eyes of fishes. Fox16 terns by individuals viewing from a distance, makes a distinction between two types of chro- as some predators might do while deciding matophores, those that contain biochromes whether to attack. (Reflective color patterns and those in which colors result from purely like blue and iridescence are expected to be de- physical properties, the schemochromes. Bio- tectable at longer distances.7) Under the same chromes are true pigments, such as carotenoids water conditions, however, the visual percep- (red, yellow, and orange), pterins (white, red, tion of the same color patterns by receivers in orange, and yellow), purines (white or silver), close proximity, like females attending to and melanins (reds, yellows, browns, and courting males, could be affected to a lesser de- blacks). Chromatophores that contain the red gree. Another environmental factor that can af- and orange carotenoids are termed ery- fect whether an organism is easily detected is throphores, and those that contain the yellow GENETIC LINKAGE AND COLOR POLYMORPHISM 67 carotenoids are termed xanthophores. Most an- Background on the southern platyfish imals do not appear to synthesize carotenoids de novo,17,18 but they can obtain carotenoid pig- The southern platyfish, X. maculatus, is a ments in their diet, including plant material, al- small, freshwater fish found in river drainages gae, and other animals. The melanin pigments of northern Central America east of the conti- are contained in chromatophores termed nental divide, ranging from the Rio Jamapa, melanophores. Melanin is a product of the ox- Veracruz, Mexico, to Belize and Guatemala (ex- idation of amino acids, such as tyrosine and cluding the Yucatan Peninsula). Coloration in tryptophan. A fourth type of biochrome, platyfish is highly variable, but the background pterinophores, contain pterins that contribute is yellowish-beige to olive-grey in coloration. to eye coloration as well as coloration of other This background coloration consists of mi- fish tissues. Pterins can be synthesized in de- cromelanophores, xanthophores, and iri- veloping pterinophores by vertebrates and dophores.20 Platyfish are found in greatest other animals.19 numbers in ponds, ditches, small lakes, and Chromatophores that do not contain true streams, but can also be found in low numbers pigment, but instead produce structural colors, in larger rivers (personal observation). The sites are called schemochromes; the color of at which platyfish occur vary in many ways, schemochromes is the result of the interaction including the presence of piscivorous fish, the of light and cell structural configuration.16 The composition of sympatric species,
Load more

Recommended publications
  • Alien Freshwater Fish, Xiphophorus Interspecies Hybrid (Poeciliidae) Found in Artificial Lake in Warsaw, Central Poland
    Available online at www.worldscientificnews.com WSN 132 (2019) 291-299 EISSN 2392-2192 SHORT COMMUNICATION Alien freshwater fish, Xiphophorus interspecies hybrid (Poeciliidae) found in artificial lake in Warsaw, Central Poland Rafał Maciaszek1,*, Dorota Marcinek2, Maria Eberhardt3, Sylwia Wilk4 1 Department of Genetics and Animal Breeding, Faculty of Animal Sciences, Warsaw University of Life Sciences, ul. Ciszewskiego 8, 02-786 Warsaw, Poland 2 Faculty of Animal Sciences, Warsaw University of Life Sciences, ul. Ciszewskiego 8, 02-786 Warsaw, Poland 3 Faculty of Veterinary Medicine, Warsaw University of Life Sciences, ul. Ciszewskiego 8, 02-786 Warsaw, Poland 4 Veterinary Clinic “Lavia-Vet”, Jasionka 926, 36-002, Jasionka, Poland *E-mail address: [email protected] ABSTRACT This paper describes an introduction of aquarium ornamental fish, Xiphophorus interspecies hybrid (Poeciliidae) in an artificial water reservoir in Pole Mokotowskie park complex in Warsaw, Poland. Caught individuals have been identified, described and presented in photographs. Measurements of selected physicochemical parameters of water were made and perspectives for the studied population were evaluated. The finding is discussed with available literature describing introductions of alien species with aquaristical origin in Polish waters. Keywords: aquarium, invasive species, ornamental pet, green swordtail, southern platyfish, variatus platy, stone maroko, Pole Mokotowskie park complex, Xiphophorus ( Received 14 July 2019; Accepted 27 July 2019; Date of Publication 29 July 2019 ) World Scientific News 132 (2019) 291-299 1. INTRODUCTION The fish kept in aquariums and home ponds are often introduced to new environment accidentaly or intentionaly by irresponsible owners. Some species of these ornamental animals are characterized by high expansiveness and tolerance to water pollution, which in the case of their release in a new area may result in local ichthyofauna biodiversity decline.
    [Show full text]
  • Summary Report of Freshwater Nonindigenous Aquatic Species in U.S
    Summary Report of Freshwater Nonindigenous Aquatic Species in U.S. Fish and Wildlife Service Region 4—An Update April 2013 Prepared by: Pam L. Fuller, Amy J. Benson, and Matthew J. Cannister U.S. Geological Survey Southeast Ecological Science Center Gainesville, Florida Prepared for: U.S. Fish and Wildlife Service Southeast Region Atlanta, Georgia Cover Photos: Silver Carp, Hypophthalmichthys molitrix – Auburn University Giant Applesnail, Pomacea maculata – David Knott Straightedge Crayfish, Procambarus hayi – U.S. Forest Service i Table of Contents Table of Contents ...................................................................................................................................... ii List of Figures ............................................................................................................................................ v List of Tables ............................................................................................................................................ vi INTRODUCTION ............................................................................................................................................. 1 Overview of Region 4 Introductions Since 2000 ....................................................................................... 1 Format of Species Accounts ...................................................................................................................... 2 Explanation of Maps ................................................................................................................................
    [Show full text]
  • An Assessment of Exotic Species in the Tonle Sap Biosphere Reserve
    AN ASSESSMENT OF EXOTIC SPECIES IN THE TONLE SAP BIOSPHERE RESERVE AND ASSOCIATED THREATS TO BIODIVERSITY A RESOURCE DOCUMENT FOR THE MANAGEMENT OF INVASIVE ALIEN SPECIES December 2006 Robert van Zalinge (compiler) This publication is a technical output of the UNDP/GEF-funded Tonle Sap Conservation Project Executive Summary Introduction This report is mainly a literature review. It attempts to put together all the available information from recent biological surveys, and environmental and resource use studies in the Tonle Sap Biosphere Reserve (TSBR) in order to assess the status of exotic species and report any information on their abundance, distribution and impact. For those exotic species found in the TSBR, it is examined whether they can be termed as being an invasive alien species (IAS). IAS are exotic species that pose a threat to native ecosystems, economies and/or human health. It is widely believed that IAS are the second most significant threat to biodiversity worldwide, following habitat destruction. In recognition of the threat posed by IAS the Convention on Biological Diversity puts forward the following strategy to all parties in Article 8h: “each contracting party shall as far as possible and as appropriate: prevent the introduction of, control, or eradicate those alien species which threaten ecosystems, habitats or species”. The National Assembly of Cambodia ratified the Convention on Biological Diversity in 1995. After reviewing the status of exotic species in the Tonle Sap from the literature, as well as the results from a survey based on questionnaires distributed among local communities, the main issues are discussed, possible strategies to combat the spread of alien species that are potentially invasive are examined, and recommendations are made to facilitate the implementation of a strategy towards reducing the impact of these species on the TSBR ecosystem.
    [Show full text]
  • The Phylogenetic Distribution of a Female Preference
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Faculty Publications in the Biological Sciences Papers in the Biological Sciences 1996 The Phylogenetic Distribution of a Female Preference Alexandra Basolo University of Nebraska - Lincoln, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/bioscifacpub Part of the Life Sciences Commons Basolo, Alexandra, "The Phylogenetic Distribution of a Female Preference" (1996). Faculty Publications in the Biological Sciences. 45. https://digitalcommons.unl.edu/bioscifacpub/45 This Article is brought to you for free and open access by the Papers in the Biological Sciences at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Faculty Publications in the Biological Sciences by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Syst. Biol. 45(3):290-307, 1996 THE PHYLOGENETIC DISTRIBUTION OF A FEMALE PREFERENCE ALEXANDRA L. BASOLO Nebraska Behavioral Biobgy Group, University of Nebraska, Lincoln, Nebraska 68510, USA; E-mail: [email protected] Abstract.—Robust phylogenetic information can be instrumental to the study of the evolution of female mating preferences and preferred male traits. In this paper, the evolution of a preexisting female bias favoring a sword in male swordtail fish and the evolution of the sword, a complex character, are used to demonstrate how the evolution of mating preferences and preferred traits can be examined in a phylogenetic context. Phylogenetic information suggests that a preference for a sword arose prior to the evolution of the sword in the genus Xiphophorus and that the sword was adaptive at its origin. A phylogenetic approach to the study of female preferences and male traits can also be informative when used in conjunction with mate choice theory in making predictions about evolutionary changes in an initial bias, both prior to the appearance of the male trait it favors and subsequent to the appearance of the trait.
    [Show full text]
  • Florida State Museum
    BULLETIN OF THE FLORIDA STATE MUSEUM BIOLOGICAL SCIENCES Volume 5 Number 4 MIDDLE-AMERICAN POECILIID FISHES OF THE GENUS XIPHOPHORUS Donn Eric Rosen fR \/853 UNIVERSITY OF FLORIDA Gainesville 1960 The numbers of THE BULLETIN OF THE FLORIDA STATE MUSEUM, BIOLOGICAL SCIENCES, are published at irregular intervals. Volumes contain about 300 pages and are not necessarily completed in any one calendar year. OLIVER L. AUSTIN, JR., Editor WILLIAM J. RIEMER, Managing Editor All communications concerning purchase or exchange of the publication should be addressed to the Curator of Biological Sciences, Florida State Museum, Seagle Building, Gainesville, Florida. Manuscripts should be sent to the Editor of the B ULLETIN, Flint Hall, University of Florida, Gainesville, Florida. Published 14 June 1960 Price for this issue $2.80 MIDDLE-AMERICAN POECILIID FISHES OF THE GENUS XIPHOPHORUS DONN ERIC ROSEN 1 SYNOPSiS. Drawing upon information from the present studies of the com« parative and functional morphology, distribution, and ecology of the forms of Xiphophorus (Cyprinodontiformes: R6eciliidae) and those made during the last ' quarter of a century on their. genetics, cytology, embryology, endocrinology, and ethology, the species are classified and arranged to indicate their probable phylo- genetic relationships. Their evolution and zoogeography are considered in rela- tion to a proposed center of adaptive radiation -on Mexico's Atlantic coastal plain. Five new forms are, described: X. varidtus evelynae, new subspecies; X, milleri, new specie-s; X. montezumae cortezi, new subspecies; X. pygmaeus 'nigrensis, new ' subspecies; X. heHeri aluarezi, new subspecies. To the memory of MYR6N GORDON, 1899-1959 for his quarter century of contributibns- to the biology of this and other groups of fishes.
    [Show full text]
  • The Endangered White Sands Pupfish (Cyprinodon Tularosa)
    The Endangered White Sands pupfish (Cyprinodon tularosa) genome reveals low diversity and heterogenous patterns of differentiation Andrew Black1, Janna Willoughby2, Anna Br¨uniche-Olsen3, Brian Pierce4, and Andrew DeWoody1 1Purdue University 2Auburn University 3University of Copenhagen 4Texas A and M University College Station November 24, 2020 Abstract The White Sands pupfish (Cyprinodon tularosa), endemic to New Mexico in Southwestern North America, is of conservation concern due in part to invasive species, chemical pollution, and groundwater withdrawal. Herein, we developed a high quality draft reference genome and use it to provide biological insights into the evolution and conservation of C. tularosa. Specifically, we localized microsatellite markers previously used to demarcate Evolutionary Significant Units, evaluated the possibility of introgression into the C. tularosa genome, and compared genomic diversity among related species. The de novo assembly of PacBio Sequel II error-corrected reads resulted in a 1.08Gb draft genome with a contig N50 of 1.4Mb and 25,260 annotated protein coding genes, including 95% of the expected Actinopterigii conserved orthologs. Many of the previously described C. tularosa microsatellite markers fell within or near genes and exhibited a pattern of increased heterozygosity near genic areas compared to those in intergenic regions. Genetic distances between C. tularosa and the widespread invasive species C. variegatus, which diverged ~1.6-4.7 MYA, were 0.027 (nuclear) and 0.022 (mitochondrial). Nuclear alignments revealed putative tracts of introgression that merit further investigation. Genome-wide heterozygosity was markedly lower in C. tularosa compared to estimates from related species, likely because of smaller long-term effective population sizes constrained by their isolated and limited habitat.
    [Show full text]
  • The Great Basin Naturalist
    STATUS OF INTRODUCED FISHES IN CERTAIN SPRING SYSTEMS IN SOUTHERN NEVADA Walter R. Courtenay, Jr.," and James E. Deacon^ .Abstract.— We record eight species of exotic fishes as established, reproducing populations in certain springs in Clark, Lincoln, and Nye counties. Nevada. These include an unidentified species of Hi/postomus, Cyprinus carpio, Poecilia mexicana. Poecilia reticulata, a Xiphophorus hybrid, and Cichlasoma nigrofasciatiim. Tilapia mariae, estab- lished in a spring near the Overton Arm of Lake Mead, and Tilapia zilli, established in a golf course pond in Pah- rump Valley, are recorded for the first time from Nevada waters. Though populations of transplanted Gambusia af- finis persist, other populations of Poecilia latipinna are apparently no longer extant. Cichlasoma severum, Notemigomis crysoleucas, Poecilia latipinna, and Carassius auratus were apparently eradicated from Rogers Spring in 1963. Miller and Alcorn (1943), Miller (1961), La of Deacon et al. (1964) and Hubbs and Dea- Rivers (1962), Deacon et al. (1964), Hubbs con (1964). and Deacon (1964), Minckley and Deacon (1968), Minckley (1973), Hubbs et al. (1974), Clark County Deacon (1979), Hardy (1980), and others re- corded the presence of non-native fishes in Indian Spring is 2 km south of U.S. High- Nevada. In those papers, it was stressed that way 95, approximately 62 km northwest of the introduction of nonnative fishes, be they Las Vegas in the village of Indian Springs. exotic (of foreign origin) or transplants native Minckley (1973) recorded a suckermouth cat- to otlier areas of the United States, can have fish {Hypostomiis) as successfully established serious, adverse impacts on the depauperate since at least 1966 "in a warm spring in and often highly endemic fish fauna in the southern Nevada"; this reference was to In- southwestern U.S.
    [Show full text]
  • Annotated Checklist of the Fish Species (Pisces) of La Réunion, Including a Red List of Threatened and Declining Species
    Stuttgarter Beiträge zur Naturkunde A, Neue Serie 2: 1–168; Stuttgart, 30.IV.2009. 1 Annotated checklist of the fish species (Pisces) of La Réunion, including a Red List of threatened and declining species RONALD FR ICKE , THIE rr Y MULOCHAU , PA tr ICK DU R VILLE , PASCALE CHABANE T , Emm ANUEL TESSIE R & YVES LE T OU R NEU R Abstract An annotated checklist of the fish species of La Réunion (southwestern Indian Ocean) comprises a total of 984 species in 164 families (including 16 species which are not native). 65 species (plus 16 introduced) occur in fresh- water, with the Gobiidae as the largest freshwater fish family. 165 species (plus 16 introduced) live in transitional waters. In marine habitats, 965 species (plus two introduced) are found, with the Labridae, Serranidae and Gobiidae being the largest families; 56.7 % of these species live in shallow coral reefs, 33.7 % inside the fringing reef, 28.0 % in shallow rocky reefs, 16.8 % on sand bottoms, 14.0 % in deep reefs, 11.9 % on the reef flat, and 11.1 % in estuaries. 63 species are first records for Réunion. Zoogeographically, 65 % of the fish fauna have a widespread Indo-Pacific distribution, while only 2.6 % are Mascarene endemics, and 0.7 % Réunion endemics. The classification of the following species is changed in the present paper: Anguilla labiata (Peters, 1852) [pre- viously A. bengalensis labiata]; Microphis millepunctatus (Kaup, 1856) [previously M. brachyurus millepunctatus]; Epinephelus oceanicus (Lacepède, 1802) [previously E. fasciatus (non Forsskål in Niebuhr, 1775)]; Ostorhinchus fasciatus (White, 1790) [previously Apogon fasciatus]; Mulloidichthys auriflamma (Forsskål in Niebuhr, 1775) [previously Mulloidichthys vanicolensis (non Valenciennes in Cuvier & Valenciennes, 1831)]; Stegastes luteobrun- neus (Smith, 1960) [previously S.
    [Show full text]
  • Aquatic Organisms F Introduced Into North America
    ERNEST A. LACHNER, Exotic Fishes and Other C. RICHARDrr'UADn r>nDT\rcROBINS ~~J WALTER R. COURTENAY, „ Aquatic Organisms f Introduced into North America SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY • 1970 NUMBER 59 SERIAL PUBLICATIONS OF THE SMITHSONIAN INSTITUTION The emphasis upon publications as a means of diffusing knowledge was expressed by the first Secretary of the Smithsonian Institution. In his formal plan for the Insti- tution, Joseph Henry articulated a program that included the following statement: "It is proposed to publish a series of reports, giving an account of the new discoveries in science, and of the changes made from year to year in all branches of knowledge." This keynote of basic research has been adhered to over the years in the issuance of thousands of titles in serial publications under the Smithsonian imprint, com- mencing with Smithsonian Contributions to Knowledge in 1848 and continuing with the following active series: Smithsonian Annals of Flight Smithsonian Contributions to Anthropology Smithsonian Contributions to Astrophysics Smithsonian Contributions to Botany Smithsonian Contributions to the Earth Sciences Smithsonian Contributions to Paleobiology Smithsonian Contributions to Zoology Smithsonian Studies in History and Technology In these series, the Institution publishes original articles and monographs dealing with the research and collections of its several museums and offices and of professional colleagues at other institutions of learning. These papers report newly acquired facts, synoptic interpretations of data, or original theory in specialized fields. These pub- lications are distributed by mailing lists to libraries, laboratories, and other interested institutions and specialists throughout the world. Individual copies may be obtained from the Smithsonian Institution Press as long as stocks are available.
    [Show full text]
  • MNU Induction of Neoplasia in a Platyfish Model Steven Kazianis, Irma Gimenez-Conti, Richard B
    0023-6837/01/8109-1191$03.00/0 LABORATORY INVESTIGATION Vol. 81, No. 9, p. 1191, 2001 Copyright © 2001 by The United States and Canadian Academy of Pathology, Inc. Printed in U.S.A. MNU Induction of Neoplasia in a Platyfish Model Steven Kazianis, Irma Gimenez-Conti, Richard B. Setlow, Avril D. Woodhead, John C. Harshbarger, David Trono, Mark Ledesma, Rodney S. Nairn, and Ronald B. Walter Department of Chemistry and Biochemistry (SK, ML, RBW), Southwest Texas State University, San Marcos, Texas; Department of Carcinogenesis, Science Park-Research Division, M. D. Anderson Cancer Center, University of Texas, Smithville, Texas (IG-C, DT, RSN); Department of Biology, Brookhaven National Laboratory, Upton, New York (RBS, ADW); and Department of Pathology (JCH), George Washington University Medical Center, Washington, D.C. SUMMARY: Interspecific hybrid crosses between members of the fish genus Xiphophorus have been used for over 70 years to study the genetic aspects of melanoma formation. In the well-established “Gordon-Kosswig” cross, the platyfish X. maculatus is outcrossed to the swordtail X. helleri, and the resulting backcross segregants spontaneously develop melanoma. We recently produced a distinct cross between X. maculatus and another platyfish species, X. couchianus. X. maculatus strain Jp 163 A is homozygous for several X-linked pigment pattern genes, including the Spotted dorsal (Sd), Dorsal red (Dr), and Anal fin spot (Af). Af is a sex-limited trait, coding exclusively for melanophores distributed on the modified anal fin or “gonopodium” in the adult male fish. Within F1 and BC1 hybrids (to X. couchianus), the Sd pigment pattern is phenotypically suppressed, whereas Dr and Af are enhanced.
    [Show full text]
  • Review Article Review of the Livebearer Fishes of Iran (Family Poeciliidae)
    Iran. J. Ichthyol. (December 2017), 4(4): 305–330 Received: June 23, 2017 © 2017 Iranian Society of Ichthyology Accepted: August 11, 2017 P-ISSN: 2383-1561; E-ISSN: 2383-0964 doi: 10.7508/iji.2016.02.015 http://www.ijichthyol.org Review Article Review of the livebearer fishes of Iran (Family Poeciliidae) Brian W. COAD Canadian Museum of Nature, Ottawa, Ontario, K1P 6P4 Canada. Email: [email protected] Abstract: The systematics, morphology, distribution, biology and economic importance of the livebearers of Iran are described, the species are illustrated, and a bibliography on these fishes in Iran is provided. There are four species including Gambusia holbrooki, Poecilia latipinna, P. reticulata and Xiphophorus hellerii. All of these species are exotics. Keywords: Biology, Morphology, Gambusia, Poecilia, Xiphophorus. Citation: Coad B.W. 2017. Review of the livebearer fishes of Iran (Family Poeciliidae). Iranian Journal of Ichthyology 4(4): 305-330. Introduction Other examples of poeciliids available in Iran The freshwater ichthyofauna of Iran comprises a and potential escapees are the molly, Poecilia diverse set of about 288 species in 107 genera, 28 sphenops Valenciennes, 1846 (e.g., Rabiei & Ziaei families, 22 orders and 3 classes (Esmaeili et al. Nejad 2013; Moghaddam et al. 2014; Pour et al. 2017a). These form important elements of the aquatic 2014), the southern platyfish, Xiphophorus ecosystem and a number of species are of maculatus (Günther, 1866) (e.g., Shoaibi Omrani et commercial or other significance. The literature on al. 2010; Tarkhani & Imanpoor 2012; Sadeghi & these fishes is widely scattered, both in time and Imanpour 2015; Alishahi et al.
    [Show full text]
  • Elevated Winter Pond Temperature and Biotic Resistance; Implications for Fish Invasion and Climate Change
    Interaction between experimentally- elevated winter pond temperature and biotic resistance; implications for fish invasion and climate change Quenton M. Tuckett & Jeffrey E. Hill ICAIS-Fort Lauderdale Funding: Support: In Florida, temperature is an important habitat filter Affects distribution of non-native fish Many non-native propagules have tropical origin Photos: huffingtonpost.com, nytimes.com Biotic Filter: strongly-interacting native species in Florida 700 c 600 Green Swordtail 500 400 300 # stocked 200 Green swordtails (#) swordtails Green b 100 b a 0 High Medium Low Control Mesocosm experiment with/without eastern mosquitofish (Gambusia holbrooki) 1 60 0.9 0.8 50 0.7 40 0.6 0.5 30 0.4 20 0.3 Swordtail fry (count) Swordtail 0.2 10 Caudal damage (qualitative score) (qualitative Caudaldamage 0.1 0 0 Control Gambusia Control Gambusia Community assembly theory applied to invasion Species Pool • Begin with species pool • Habitat filter: is habitat suitable? Habitat Filter • Biotic filter: species interactions Biotic Filter • Arrive at species subset Species Subset • Neutral processes also important Need to consider potential for interactions Species Pool Habitat Filter Biotic Filter Species interactions Habitat alters alter habitat suitability species interactions Species Subset Two widely introduced poeciliids: Southern Platyfish (Xiphophorus maculatus) Guppy (Poecilia reticulata) Southern Platyfish (GBIF) Guppy (Deacon et al. 2011) • Southern Platyfish: Mexico to Belize • Guppy: Lesser Antilles, northern South America • May lack
    [Show full text]