Genetics and Mutagenesis of Fish Edited by J. H. Schroder
With Contributions by
F. W. Allendorf, A. Anders' F. Anders' N. Egami . W. Engel H. O. Hodgins' S. Holzberg . Y. Hyodo-Taguchi . A. G. Johnson K. D. Kallman' V. S. Kirpichnikov . K. Klinke' C. Kosswig K. Lepper' R. F. Lincoln' W. Lueken· Ch. Meske' J. L. Mighell E. T. Miller' S. Ohno . J. Parzevall . G. Peters' N. Peters' A. Post C. E. Purdom . D. L. Pursglove· H.-H. Reichenbach-Klinke H.-H. Ropers' N. Satoh . J. J. Scheel . E. R. Schmidt· A. Scholl J. H. Schroder' R. J. Schultz· M. Schwab' J. B. Shaklee . F. M. Utter J. Vielkind . U. Vielkind . G. S. Whitt· H. Wilkens' U. Wolf D. S. Woodhead
With 132 Figures
Springer-Verlag' Berlin' Heidelberg· New York 1973
Dr. Johannes Horst Schroder Institut fUr Biologie Gesellschaft fUr Strahlen- und Umweltforschung D 8042 Neuherberg/Munich
ISBN-13: 978-3-642-65702-3 DOl: 10.1007/978-3-642-65700-9
e-ISBN-13: 978-3-642-65700-9
This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocoping machine or similar means, and storage in data banks.
Under § 54 of the German Copyright Law, where copies are made for other than private use, a fee is payable to the publisher, the amount of the fee to be determined by agreement with the publisher.
The use of general descriptive names, trade names, trade marks etc. in this publication, even if the former are not especially identified, is not to be taken as a sign that such names, as understood by the Trade Marks and Merchandise Marks Act, may accordingly be used freely by anyone.
© by Springer-Verlag Berlin· Heidelberg 1973. Library of Congress Catalog Card Number 73-11601.
Softcover reprint of the hardcover 1 st edition 1973
Genetics and Mutagenesis of Fish Edited by J. H. Schroder
With Contributions by
F. W. Allendorf· A. Anders . F. Anders . N. Egami . W. Engel H. O. Hodgins' S. Holzberg . Y. Hyodo-Taguchi . A. G. Johnson K. D. Kallman' V. S. Kirpichnikov . K. Klinke' C. Kosswig K. Lepper' R. F. Lincoln' W. Lueken' Ch. Meske' J. L. Mighell E. T. Miller' S. Ohno . J. Parzevall . G. Peters' N. Peters' A. Post C. E. Purdom' D. L. Pursglove' H.-H. Reichenbach-Klinke H.-H. Ropers . N. Satoh . J. J. Scheel' E. R. Schmidt· A. Scholl J. H. Schroder' R. J. Schultz· M. Schwab' J. B. Shaklee . F. M. Utter J. Vielkind . U. Vielkind . G. S. Whitt· H. Wilkens' U. Wolf D. S.Woodhead
With 132 Figures
Springer-Verlag· New York· Heidelberg· Berlin 1973
Dr. Johannes Horst Schroder Institut fUr Biologie Gesellschaft fUr Strahlen- und Umweltforschung D 8042 Neuherberg/Munich
ISBN-13: 978-3-642-65702-3 e-ISBN-13: 978-3-642-65700-9 DOl: 10.1007/978-3-642-65700-9
This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocoping machine or similar means, and storage in data banks.
Under § 54 of the German Copyright Law, where copies are made for other than private use, a fee is payable to the publisher, the amount of the fee to be determined by agreement with the publisher.
The use of general descriptive names, trade names, trade marks etc. in this publication, even if the former are not especially identified, is not to be taken as a sign that such names, as understood by the Trade Marks and Merchandise Marks Act, may accordingly be used freely by anyone.
© by Springer-Verlag Berlin' Heidelberg 1973. Library of Congress Catalog Card Number 73-11601.
Softcover reprint of the hardcover 1 st edition 1973
Preface
The present volume contains papers presented on the occasion of the Ichthyological Symposium on Genetics and Mutagenesis held on October 13 through 15, 1972 at the Biology Institute of the Association for Radiation and Environmental Research in Neuherberg near Munich, Germany. These symposia have been held annually since 1955 by former students of Prof. C. Kosswig and Prof. F. Anders in Hamburg or Giessen. In the last two years attendance has increased beyond the national German basis, but the Neuherberg meeting of fish geneticists was the first that could be called "international", the participants coming from twelve different countries. The organization of this meeting was made possible by the support of the Association for Radiation and Environmental Research, which provided the financial backing; special thanks are due to Min.Rat. H. Costa and Dr. R. Wittenzellner. The scientific advice and encouragement of the Director of the Biology Institute, Prof. O. Hug, was also much appreciated, as was the helpful assistance of Dr. B. Betz and Dr. K. Gottel. In addition, I have to thank my colleagues and coworkers Mdmes. E. Neubner, I.S. Otten, and K. Peters, Messrs. M. Murr and M. Wiestner, and Dr. S. Holzberg for their help in organizing the meeting.
Apart from the papers presented at the above symposium, we have included some papers by colleagues who were unable to attend the meeting. The contents of this volume may thus be considered 'representative of current research on the genetics and mutagenesis of fish.
First there is a historical review indicating the importance of fish in the study of genetics, by Prof. Dr. C. Kosswig, himself one of the founders of ichthyogenetics in a broad sense. Subsequent contributions are arranged according to the main features of ichthyogenetics: sex determination and melanoma formation; mutagenesis; chromosomes and cytology; ethology; evolution; and biochemistry. Such an arrangement is, of course artificial, but helpful for locating certain topics. For example, the paper by Holzberg on inherited changes in male aggressiveness in postirradiation generations of convict cichlids could have been placed in either the mutagenesis or the ethology chapter of this book, since aggressiveness is a behavioural trait.
Some of the papers give monograph-type summaries of certain areas in fish genetics, while others go into detail, for instance, Kallman's paper on the geographical distribution of homo- and heterogametic females and males within the species, xiphophorus maculatus. Japanese fish geneticists present a preliminary report on sex determination in the germ cells of transplanted gonads as compared to normal gonads of the medaka, Oryzias latipes. Anders and coworkers summarize their recent studies concerning the inheritance and mutagenesis of the regulation system of melanomas in xiphophorin fish.
The next chapter deals with mutagenesis in fish, a topic already mentioned in the preceding chapter on sex determination and melanoma formation. Purdom and Woodhead survey genetic and somatic radiation damage in fish, ionizing radiation being the only mutagenetic agent so far used systematically in fish mutagenesis. Egami and Hyodo-Taguchi describe dosemutation relationships in dominant lethal mutations after irradiation of
either female or male germ cells of the medaka. Purdom and Lincoln discuss radiation-induced gynogenesis in marine flatfish, which can even lead to triploid forms. These results are not merely of theoretical interest, they also have practical significance, because it is now possible to obtain homozygous strains without several generations of inbreeding. Genetically well-defined strains are a prerequisite for fish breeding. Intensive farming of both sea and freshwater fish is the only way to ensure increased supplies of this important source of animal protein. Exploitation of marine fish alone would soon lead to a complete exhaustion of natural populations and endanger the nutritional basis of the constantly growing human population.
My own paper is a short survey of fish mutagenesis with the aim of encouraging geneticists to use teleostean fish which have proved an excellent tool for studying mutagenesis.
In the chapter on chromosomes and cytology, Post describes unusual karyotypes of two species and Scheel deals with the chromosomes of some anuran species. This author's earlier work on chromosomes has been very important in elucidating the evolutionary processes of African cyprinodontiform fish. He is now continuing his work with frogs, so providing more information on the evolution of karyotypes in lower vertebrates. Vielkind et al. describe the incorporation of tritiated thymidine into the DNA of melanotic and amelanotic melanoma explants and the fate of bacterial DNA in embryos of poeciliid fish. Lueken et al. discuss the arrangement of pigment cells in pure-breeding strains and interspecific hybrids of xiphophorin fish. Meske describes the spermatozoa of eels bred to sexual maturity under experimental conditions.
The chapter on ethology contains only two contributions. As already mentioned, Holzberg reports his preliminary results on the aggressiveness of F2 cichlid males after ancestral irradiation in connection with the male aggressiveness of the precedent generation, whereas Parzefall deals with the sexual behaviour of Poecilia (Mollienesia) sphenops. The chapter on evolution exposes some problems of evolutionary processes in vertebrates. Poeciliid fish are very useful for such studies since they produce fertile inter-specific hybrids. The regressive evolution of cavernicolous forms was investigated by crossing the normal-eyed river fish with its subterristic blind and depigmented derivatives in the Astyanax complex. Stimulated by Kosswig, both Peters and Wilkens successfully used these characinid fish as model for the genetics of regressive evolution. Schultz discovered all-female populations which propagate by "hybridogenesis" and was successful in synthesizing an all-female "species" under laboratory conditions, thus justifying his hypothesis on the natural origin of hybridogenetic populations in the Poeciliopsis group of poeciliid fish. Ohno reviews recent results on evolution at the molecular level and explains his now widely accepted view on the conservative nature of selection and the importance of gene duplication and "junk" DNA for evolutionary processes in vertebrates.
The final chapter covers biochemical studies of fish, a topic which has grown in importance during the last decade. Kirpichnikov describes biochemical polymorphism from the evolutionary point of view, whereas Whitt et al., discussing dehydrogenase isozymes of fish, adopt the standpoint of developmental and biochemical genetics. Scholl confines himself to the biochemical evolution and tissue-specific expression of 6-phosphogluconate dehydrogenase within the genus Xiphophorus. ReichenbachKlinke deals with the possible application of serum polymorphism in fish for the purpose of breeding strains resistant to various bacteria. Wolf and coworkers discuss the inheritance of NADP-dependent isocitrate dehydrogenase in the rainbow trout. Finally Utter et al. examine the
inheritance and the application of biochemical variants to population studies in sea-water fish.
Prof. Kosswig's 70th birthday falls on 30 October 1973, and it is a pleasure to dedicate this volume on Genetics and Mutagenesis of Fish to him. I have to thank all the colleagues who unanimously agreed with this dedication. The appreciation of Curt Kosswig's scientific life by F. Anders is gratefully acknowledged.
Neuherberg, April 1973 Johannes Borst Schroder
Contents
1. Historical Review
The Role of Fish in Research on Genetics and Evolution ......... 3 C. Kosswig
2. Sex-Determination and Melanoma Formation
The Sex-Determining Mechanism of the Platyfish, XiphophoruB maculatuB ...................................................... 19 K.D. Kallman
Preliminary Report on Sex Differentiation in Germ Cells of Normal and Transplanted Gonads in the Fish, Oryzias latipeB ........................................................ 29 N. Satoh and N. Egami
Regulation of Gene Expression in the Gordon-Kosswig Melanoma System ................................................ 33
I. The Distribution of the Controlling Genes in the Genome of the Xiphophorin Fish, Platypoecilus maculatuB and Platypoeci lUB varia tUB ......................................... 33 A. Anders, F. Anders, and K. Klinke
II. The Arrangement of Chromatophore Determining Loci and Regulating Elements in the Sex Chromosomes of Xiphophorin Fish, PlatypoeciluB maculatuB and PlatypoeciluB varia tUB ............•.......................................... 53 A. Anders, F. Anders, and K. Klinke
3. Mutagenesis
Radiation Damage in Fish ....................................... 67 C.E. Purdom and D.S. Woodhead
Dominant Lethal Mutation Rates in the Fish, OryziaB latipes, Irradiated at Various Stages of Gametogenesis .................. 75 N. Egami and Y. Hyodo-Taguchi
Chromosome Manipulation in Fish C.E. Purdom and R.F. Lincoln
83
Teleosts as a Tool in Mutation Research ........................ 91 J.H. Schroder
x
4. Chromosomes and Cytology
Chromosomes of Two Fish-Species of the Genus Diretmus (Osteichthyes, Beryciformes: Diretmidae) ....................... 103
A. Post
The Chromosomes of Some African Anuran Species ................. 113 J.J. Scheel
Incorporation of H3-Thymidine into the DNA of Melanotic and Amelanotic Melanoma Explants after Whole-Body X-Irra-diation of Melanoma-Bearing Platyfish-Swordtail Hybrids ........ 117 J. Vielkind, D.L. Pursglove, and U. Vielkind
Fate of Bacterial DNA Injected into Embryos of Poeciliid Fish ............ , ..................... , ........................ 123 J. Vielkind, M. Schwab, and F. Anders
Regulation of the Pigment Cell Arrangements in Species and Interspecies Hybrids of Xiphophorus (Pisces, Poeciliidae) by Cellular Interactions on the Fish Body ...................... 139 W. Lueken, E.R. Schmidt, and K. Lepper
Experimentally Induced Sexual Maturity in Artificially Reared Male Eels (Anguilla anguilla) ........................... 161 Ch. Meske
5. Ethology
Change of Aggressive Readiness in Post-Irradiation Generations of the Convict Cichlid Fish, Cichlasoma nigrofasciatum ......... 173 S. Holzberg
Attraction and Sexual Cycle of Poeciliids ...................... 177 J. Parzefall
6. Evolution
Genetic Problems in the Regressive Evolution of Cavernicolous Fish ........................................................... 187 N. Peters and G. Peters
Phylogenetic Age and Degree of Reduction of Cave Animals ....... 203 H. Wilkens
Origin and Synthesis of a Unisexual Fish ....................... 207 R.J. Schultz
Fish and Nature's Extensive Experiments with Gene Duplication .................................................... 213 S. Ohno
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7. Biochemistry
Biochemical Polymorphism and Microevolution Processes in Fish ............. , ........ , ................................. 223 V.S. Kirpichnikov
Developmental and Biochemical Genetics of Lactate Dehydrogenase Isozymes in Fishes ............................... 243 G.S. Whitt, E.T. Miller, and J.B. Shaklee
Biochemical Evolution in the Genus Xiphophorus (Poeciliidae, Teleostei) ....................................... 277 A. Scholl
Tissue-Specific Preferential Expression of the Xiphophorus xiphidium Allele for 6-Phosphogluconate Dehydrogenase in Interspecific Hybrids of Platyfish (Poeciliidae, Teleostei) ....................•....•................•.......... 301 A. Scholl and F. Anders
Investigations on the Serum Polymorphism of Trout and Carp ...••...............................•.................. 315 H.-H. Reichenbach-Klinke
Inheritance of the S-Form of NADP-Dependent Isocitrate Dehydrogenase Polymorphism in Rainbow Trout '" ................. 319 H.-H. Ropers, W. Engel, and U. Wolf
Biochemical Variants in Pacific Salmon and Rainbow Trout: Their Inheritance and Application in Population Studies ........ 329 F.M. Utter, H.O. Hodgins, F.W. Allendorf, A.G. Johnson, and J.L. Mighell
Subject Index .................................................. 341
Author Index
Allendorf, F.W., Northwest Fisheries Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard East, Seattle, Wash. 98112, USA
Anders, A., Genetisches Institut der Universitat, Leihgesterner Weg 112-114, 6300 GieBen, W. Germany
Anders, F., Genetisches Institut der Universitat, Leihgesterner Weg 112-114, 6300 GieBen, W. Germany
Egami, N., Zoological Institute, Faculty of Science, University of Tokyo, Tokyo 113, Japan
Engel, W., Institut fur Hurnangenetik und Anthropologie der Universitat, Albertstr. 11, 7800 Freiburg i. Breisgau, W. Germany
Hodgins, H.O., Northwest Fisheries Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard East, Seattle, Wash. 98112, USA
Holzberg, S., Gesellschaft fur Strahlen- und Umweltforschung, Institut fur Biologie, Ingolstadter Landstr. 1, 8042 Neuherberg, W. Germany
Hyodo-Taguchi, Y., Zoological Institute, Faculty of Science, University of Tokyo, Tokyo 113, Japan
Johnson, A.G., Northwest Fisheries Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard East, Seattle, Wash. 98112, USA
Kallman, K.D., Osborn Laboratories of Marine Sciences, New York Zoological Society, Brooklyn, N.Y. 11224, USA
Kirpichnikov, V.S., Institute of Cytology Ac. Sci. USSR, Makline Avenue 32, Leningrad F-121, USSR
Klinke, K., Genetisches Institut der Universitat, Leihgesterner Weg 112-114, 6300 GieBen, W. Germany
Kosswig, C., Zoologisches Institut und Zoologisches Museum, Papendarnrn 3, 2000 Hamburg 13, W. Germany
Lepper, K., Genetisches Institut der Universitat, Leihgesterner Weg 112-114, 6300 GieBen, W. Germany
Lincoln, R.F., Ministry of Agriculture, Fisheries and Food, Fisheries Laboratory, Pakefield Road, Lowestoft, Suffolk, Great Britain
Lueken, W., Genetisches Institut der Universitat, Leihgesterner Weg 112-114, 6300 GieBen, W. Germany
Meske, C., Bundesforschungsanstalt fur Fischerei, AuBenstelle Ahrensburg, 207 Ahrensburg, W. Germany
Mighell, J.L., Northwest Fisheries Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard East, Seattle, Wash. 98112, USA
Miller, E.T., Department of Zoology, University of Illinois, Urbana, Ill. 61801, USA
Ohno, S., Department of Biology, City of Hope Medical Center, Duarte, Calif. 91010, USA
Parzefall, J., Zoologisches Institut und Museumder Universitat, Papendarnrn 3, 2000 Hamburg 13, W. Germany
Peters, G., Institut fur Hydrobiologie und Fischereiwissenschaft der Universitat, Olbersweg 24, 2000 Hamburg 50, W. Germany
Peters, N., Institut fUr Hydrobiologie und Fischereiwissenschaft der Universitat, Olbersweg 24, 2000 Hamburg 50, W. Germany
Post, A., Bundesforschungsanstalt fUr Fischerei, Institut fUr Seefischerei, Palmaille 9, 2000 Hamburg 50, W. Germany
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Purdom, C.E., Ministry of Agriculture, Fisheries and Food, Fisheries Laboratory, Pakefield Road, Lowestoft, Suffolk, Great Britain
Pursglove, D.L., Genetisches Institut der Universitat, Leihgesterner Weg 112-114, 6300 GieBen, W. Germany
Reichenbach-Klinke, H.-H., Zoologisches-Parasitologisches Institut der Tierarztlichen Fakultat, Universitat MUnchen, Kaulbachstr. 37, 8000 MUnchen 22, W. Germany
Ropers, H.-H., Institut fUr Humangenetik und Anthropologie der Universitat, Albertstr. 11, 7800 Freiburg i. Breisgau, W. Germany
Satoh, N., Zoological Institute, Faculty of Science, University of Tokyo, Tokyo 113, Japan
Scheel, J.J., Abrinken 95, 2830 Virum, Denmark Schmidt, E.R., Genetisches Institut der Universitat, Leihgesterner
Weg 112-114, 6300 GieBen, W. Germany Scholl, A., Zoologisches Institut der Universitat, Sahlistr. 8,
3000 Bern, Schweiz Schroder, J.H., Gesellschaft fUr Strahlen- und Umweltforschung,
Institut fUr Biologie, Ingolstadter Landstr. 1, 8042 Neuherberg, W. Germany
Schultz, R.J., Biological Sciences Group, University of Connecticut, Storrs, Conn. 06268, USA
Schwab, M., Genetisches Institut der Universitat, Leihgesterner Weg 112-114, 6300 GieBen, W. Germany
Shaklee, J.B., Department of Zoology, University of Illinois, Urbana, Ill. 61801, USA
Utter, F.M., Northwest Fisheries Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard East, Seattle, Wash. 98112, USA
Vielkind, J., Genetisches Institut der Universitat, Leihgesterner Weg 112-114, 6300 GieBen, W. Germany
Vielkind, U., Genetisches Institut der Universitat, Leihgesterner Weg 112-114, 6300 GieBen, W. Germany
Whitt, G.S., Department of Zoology, University of Illinois, Urbana, Ill. 61801, USA
Wilkens, H., Zoologisches Institut und Zoologisches Museum, Papendarnrn 3, 2000 Hamburg 13, W. Germany
Wolf, U., Institut fUr Humangenetik und Anthropologie der Universitat, Albertstr. 11, 7800 Freiburg i. Breisgau, W. Germany
Woodhead, D.S., Ministry of Agriculture, Fisheries and Food, Fisheries Laboratory, Pakefield Road, Lowestoft, Suffolk, Great Britain
Curt Kosswig on his 70th Birthday
Curt Kosswig will complete his 70th year on the 30th of October 1973. Friends and students wish him the heartiest birthday and dedicate to him this volume as a token of their respect and gratitude. At the same time they congratulate him on his successful work as a researcher and teacher and thank him for the untiring attention to detail which he paid to the basis of fish genetics in yearly workshops. An American colleague formulated appropriately: "Kosswig is the nucleus of the European Ichthyology".
Curt Kosswig was born in Berlin, studied there, and, in Dahlem early in his scientific career, worked as a student in a unique circle of friends with Erwin Baur on the problems of the genetics of animal husbandry in rabbits and swine. He has completely retained the sense for the practical aspect of genetics as have all other former students of Baur. He can be as much at home in applied science as he is in basic research. It is a credit to his outstanding gift as a teacher that he was appointed as director of the Zoological Institute and the Museum of Natural History in Braunschweig when he was just 29, two years after the "Habilitation" by Leopold von Ubisch in Munster. In the period following this came his first and most important research in Germany, first disputed, then recognized world-wide, with genetic sex determination without sex chromosomes and with the evolution of sex chromosomes for which he found an outstanding object in platyfish and swordtails. At the same time came also his first work on melanomas in platyfishjswordtail hybrids, discovered by him, which he accomplished partly alone, partly with his friend and colleague Hans Breider. The interpretation at that time, - that certain genes which normally determine the color pattern of the platyfish would fall to an abnormally strong action in the hybrid genome and from this originates the formation of melanomas, - is valid still today. With that, tumor formation in the platyfishjswordtail hybrids became a problem of gene regulation, and all cancer researchers today who perceive the problem of cancerogenesis as one of gene regulation rely on the work of Curt Kosswig, whether they realize it or not.
The fruitful years in Braunschweig were suddenly interrupted in 1937 when he, like many other important men, was forced at that time to flee from Germany. Turkey accepted him and gave him and his family a second home. In Istanbul he founded new laboratories and institutes; he gathered new students around him and advanced their talents; he wrote three biology text books; and he accepted guest professorships in Bagdad, Damascus, Cairo, Alexandria and Jerusalem. At the same time he shifted the emphasis of his work and of that suggested by him to historical zoogeography and hydrobiology in the Middle and Near East, in the Mediterranian Ocean and Black Sea, especially though, in the far Anatolias from Izmir to Erzurum in the headwaters of the Euphrates where he was involved in the foundation of Ataturk University and was engaged as a guest professor from 1968 until a short time ago. The study of zoogeography has undoubtedly stimulated him to further work with speciation and degenerative evolution which had already interested him for a long time in his experiments with wood-
XVI
lice, fish, and birds. It is characteristic for Curt Kosswig that he undertook these projects with all available resources in large-scale plans by expedition to the Near East, Peru, Bolivia, the Philipines and Mexico.
In the mean time he was appointed in 1955 as director of the Institute of Zoology and the Zoological Museum in Hamburg, and here continued, with new colleagues and circle of friends the work that he had started in Braunschweig and Istanbul. It is a sign of his allegiance to his second home, Anatolia, that he did not give up his house on the Bosporus but uses it as an intermediate station for excursions and expeditions with his students and colleagues from Hamburg. After his self-proposed retirement at 65 he lives partly at the Bosporus and partly at the Elba.
In a rich life like Curt Kosswig lived and lives, despite several humiliations, honors are a natural occurrence. To these belong honorary memberships in respected scientific societies, honorary doctorates and other honorary distinctions. For Curt Kosswig there are many' other small honors from his friends when they worked up the material of his expeditions and found he had discovered with reliable instinct animal species unknown up to now: 5 genera and more than 40 species and subspecies are named after Curt Kosswig.
We wish that Curt Kosswig whose birthday we are celebrating will be able to continue his work in the service of our science, with his robust nature and creative power, for many many years.
Fritz Anders