Dokument-ID Dokumenttyp Verfasser/Autoren Herausgeber Haupttitel Abstract Auflage Verlagsort Verlag Erscheinungsjahr Seitenzahl Schriftenreihe Titel Schriftenreihe Bandzahl ISBN Quelle der Hochschulschrift Konferenzname Quelle:Titel Quelle:Jahrgang Quelle:Heftnummer Quelle:Erste Seite Quelle:Letzte Seite URN DOI Abteilungen OPUS4-5370 Wissenschaftlicher Artikel Schartl, Manfred; Schlupp, Ingo; Schartl, Angelika; Meyer, Manfred K.; Nanda, Indrajit; Schmid, Michael; Epplen, Jörg T.; Parzefall, Jakob On the stability of dispensable constituents of the eukaryotic genome: Stability of coding sequences versus truly hypervariable sequences in a clonal vertebrate, the amazon molly, Poecilia formosa In dooal unisexual vertebrales, the genes specifying the males become dispensable. To study tbe rate of such geoes the gynogeoetic all-female fisb Poecilillfonnolll was treated with androgens. Phenotypic males were obtained that exbibited the complete set of male cbaracteristics of dosely related gooocboristic species, induding body proportions, pigmentation, the extremely complex insemination apparatus of poecilüd fish, sexual bebavior, and spermatogeoesls. Tbe apparent stabllity of such genic structures, induding those involved in androgen regulation, is contrasted by high instability of noncoding sequeaces. Frequent mutations, thelr donal transmission, and at least two truly hypervariable Iod leading to individual difl'ereaces between these othenrise donal organisms were detected by DNA fingerprinting. These observations substantiate the concept that also in "ameiotic" vertebrates certain compartments of the genome are more prooe to mutatiooal alterations than others. 1991 urn:nbn:de:bvb:20-opus-61731 Theodor-Boveri-Institut für Biowissenschaften OPUS4-5366 Wissenschaftlicher Artikel Nanda, Indrajit; Schartl, Manfred; Feichtinger, Wolfgang; Epplen, Jörg T.; Schmid, Michael Early stages of sex chromosome differentiation in fish as analysed by simple repetitive DNA sequences Animal sex chromosome evolution has started on different occasions with a homologous pair of autosomes leading to morphologically differentiated gonosomes. In contrast to other vertebrate classes, among fishes cytologically dernonstrahle sex chromosomes are rare. In reptiles, certain motifs of simple tandemly repeated DNA sequences like (gata)\(_n\)/(gaca)\(_m\) are associated with the constitutive heterochromatin of sex chromosomes. In this study a panel of simple repetitive sequence probes was hybridized to restriction enzyme digested genomic DNA of poeciliid fishes. Apparent male heterogamety previously established by genetic experiments in Poecilia reticulata (guppy) was correlated with male-specific hybridization using the (GACA)\(_4\) probe. The (GATA)\(_4\) oligonucleotide identifies certain male guppies by a Y chromosomal polymorphism in the outbred population. In cantrast none of the genetically defined heterogametic situations in Xiphophorus could be verified consistently using the collection of simple repetitive sequence probes. Only individuals from particular populations produced sex-specific patterns of hybridization with (GATA)\(_4\). Additional poeciliid species (P. sphenops, P. velifera) harbour different sex-specifically organized simple repeat motifs. The observed sex-specific hybridization patterns were substantiated by banding analyses of the karyotypes and by in situ hybridization using the (GACA)\(_4\) probe. 1992 urn:nbn:de:bvb:20-opus-61715 Theodor-Boveri-Institut für Biowissenschaften OPUS4-5342 Wissenschaftlicher Artikel Schlupp, Ingo; Parzefall, Jakob; Epplen, Jörg T.; Nanda, Indrajit; Schmid, Michael; Schartl, Manfred Pseudomale behaviour and spontaneous masculinization in the all-female teleost Poecilia formosa (Teleostei: Poeciliidae) Pseudosexual behaviour is a rare phenomenon associated with unisexuality in vertebrates. In the gynogenetic, all-female teleost Poecilia formosa, rare individuals occur that resemble males of closely related gonochoristic species both in behaviour and external morphology. These masculinized gynogens and normal gynogens are members of the same clone, as demonstrated by DNA-fingerprinting. The behaviour of these masculinized gynogens is described and compared to the behaviour of the gonochoristic species Poecilia mexicana, P. latipinna and their hybrid as weil as androgen-treated individuals of P. formosa. No statistically significant difTerences were found between masculinized gynogens and hormonetreated individuals nor between the gonochoristic P. mexicana and P. latipinna males. Differences exist between gonochoristic and unisexual species. Passihle causes and effects of masculinized gynogens are discussed. 1992 urn:nbn:de:bvb:20-opus-61688 Theodor-Boveri-Institut für Biowissenschaften OPUS4-5339 Wissenschaftlicher Artikel Nanda, Indrajit; Schartl, Manfred; Epplen, Jörg T.; Feichtinger, Wolfgang; Schmid, Michael Primitive sex chromosomes in poeciliid fishes harbor simple repetitive DNA sequences The demonstration ofthe chromosomal mode ofsex determinationvia genetic experiments as well as the absence of heteromorphic sex chromosomes affirm poeciliid fishes as a unique group among vertebrates that are endowed with the mostprimitive form of sex chromosornes. In many different taxa the evolutionary process involved in the differentiation ofadvanced sex chromosomes is outlined through sex specifically organized repetitive sequences. In this investigation hydridization of synthetic probes specific to genomic simple repeat motifs uncovers a sex-specific hybridization pattern in certain viviparaus fishes ofthe family Poeciliidae. The hybridization pattern together with specific staining ofthe constitutive heterochromatin by C-banding reveals heterogamety in males (Poecilia reticulata) as weil as in females (P. sphenops). In P. velifera, however, C-banding alone fails to unravel the heterogametic status. The female specific W-chromosome can be detected by simple repetitive sequence probes. Therefore, the principal significance of heterochromatization as a means of generating differentiated sex chromosomes is evident. 1993 urn:nbn:de:bvb:20-opus-61659 Theodor-Boveri-Institut für Biowissenschaften OPUS4-5338 Wissenschaftlicher Artikel Schartl, Manfred; Erbelding-Denk, Claudia; Holter, Sabine; Nanda, Indrajit; Schmid, Michael; Schroder, Johannes H.; Epplen, Jörg T. Reproductive failure of dominant males in the poeciliid fish Limia perugiae determined by DNA fingerprinting Hierarchical structures among male indlviduals in a population are frequently reflected ln differences in aggressive and reproductive behavior and access to the females. In general, sodal dominance requires the Investments, which in turn then may have to be compensated for by high reproductive success. However, this hypothesls has so far only been sufficiently tested in small mating groups (one or two males with one or two females) due to the difficulties of determining paternity by conventional methods. DNA fingerprinting overcomes these problems by offering the possibility to determine genetic relationships and mating patterns within larger groups [Borke, T. (1989) Trends Ecol. Evol. 4, 139-144]. We show here that in the poecUiid fish Limia perugitu, in small matlng groups the dominant male has 8 mating success of 100%, whereas ln larger groups lts contribution to the offspring unexpectedly drops to zero. 1993 urn:nbn:de:bvb:20-opus-61643 Theodor-Boveri-Institut für Biowissenschaften OPUS4-5314 Wissenschaftlicher Artikel Erbelding-Denk, Claudia; Schroder, Johannes H.; Schartl, Manfred; Nanda, Indrajit; Schmid, Michael; Epplen, Jörg T. Male polymorphism in Limia perugiae (Pisces: Poeciliidae) The male-polymorphic poeciliid fish, Limia perugiae, a small teleostean endemic to the southeast of the Caribbean island Hispafiola, consists of three male size morphs with uniform females. Large males differentiate at a size va:rying between 25 and 38 mm; intermediate males, between 21 and 25 mm. Under competition, !arge males exhibit an elaborate courtship display, whereas small males show only a sneak-chase behavior. Intermediate males adapt their tactics to the respective competitors. However, all malemorphs can switch from courtship display to sneak-chase behavior. In large mating groups with four males of different size and five or six virgin females, large dominant a-males as weil as small subordinate \(\delta\)-males did not produce any offspring. Unexpectedly, all progeny were sired exclusively by the intemediate subordinate ß- and \(\gamma\)-males. Breeding experiments with the three male morphs can best be explained by a model of Y -linked genes for small and !arge size which are both suspended by the activity of an autosomal recessive repressor responsible for the development of intermediate males. The dominant allele of the recessive repressor, in either its homoorits heterozygous state, activates the Y-chromosomal genes for !arge or small size, respectively. Accordingly, intermediate males may produce male offspring of all size classes, depending on the presence of either the Y-linked gene or the autosomal repressor. 1994 urn:nbn:de:bvb:20-opus-61573 Theodor-Boveri-Institut für Biowissenschaften