Orb-weavers (Araneidae) are a diversified spider family comprising more than 3,100 species in more than 170 genera. Together with 13 other families, they con- stitute to superfamily Araneoidea. The presented thesis focuses on karyotype evo- lution of Araneidae, including its comparison with a related family Tetragnathidae. The results obtained from 19 araneid and four tetragnathid species confirm previ- ously postulated hypothesis that the ancestral karyotype of Araneoidea (including Araneidae) consists of 24 acrocentric chromosomes in males, including two acro- centric X chromosomes of system X1X20. However, there is a tendency of 2n decrease in some araneids due to centric fusions. In these cases, centric fusions affected most autosomes (and sometimes gonosomes as well); number of chromosome pairs de- creased from 11 to six. Three independent reduction events were detected in this thesis. Furthermore, pattern of nucleolar organizer regions (NORs) was studied in this thesis using fluorescent in situ hybridization, since data on evolution of this marker are scarce in spiders. Striking variability in NORs number was discovered, ranging from one to 13 loci. Remarkably, multiple centric fusions were always ac- companied by considerable increase of NORs number. In araneids and tetragnathids possessing...

- ABSTRACT - Among vertebrates, reptiles represent the ideal group for the study of sex determination. Reptiles include lineages with environmental sex determination (ESD) as seen in crocodiles and tuatara, lineages with genotypic sex determination (GSD), like e.g. iguanas, chameleons, skinks, lacertid lizards and birds, and few groups which possess variability in sex determination mechanisms, i.e. geckos, dragon lizards and turtles. This thesis is focused on the evolution of sex chromosomes and sex determination in turtles. The majority of turtle species exhibit ESD, which is considered the ancestral sex determination system of this group, while GSD either as male or female heterogamety evolved independently at least five times. We investigated the presence of sex chromosomes in representative species of turtles by cytogenetic analyses. The analyses included the reconstruction of karyotypes, distribution of constitutive heterochromatin (C-banding, methylation analysis) and repetitive elements (fluorescence in situ hybridization) and comparative genome hybridization (CGH), which often characterize the degenerated Y or W and can be helpful in the identification of "cryptic" sex chromosomes. We described XX/XY sex chromosomes in seven previously unstudied Australasian chelids (Pleurodira) from the genera...

- ABSTRACT - Snakes (Serpentes) are a group of squamate reptiles (Squamata) that represents more than one third of the total reptile species diversity. Snake karyotype is generally conserved with the most common chromosome number of 36 (16 macro- and 20 microchromosomes) in diploid state. It is believed that this karyotype was also present in the common ancestor of all snakes. The majority of snake species belong to the group Caenophidia and share homologous ZW sex chromosomes. Snakes from the groups "Scolecophidia" and "Henophidia" have mostly poorly differentiated, homomorphic sex chromosomes, which made them impossible to distinguish from the autosomes in the past. These snakes were for many years assumed to have ZW sex chromosomes as well. However, recent studies demonstrated not only ZW but also two non- homologous XY sex chromosome systems in non-caenophidian snakes and thus the sex determination systems in snakes are much more variable than previously thought. In this thesis, eight species of henophidian snakes (representatives from the genera Eryx, Cylidrophis, Python and Tropidophis) and one caenophidian species (Ophiophagus hannah) were examined using conventional and molecular cytogenetic methods. However, sex chromosomes were not detected in the henophidian species, only in Ophiophagus hannah,...

Orb-weavers (Araneidae) are a diversified spider family comprising more than 3,100 species in more than 170 genera. Together with 13 other families, they con- stitute to superfamily Araneoidea. The presented thesis focuses on karyotype evo- lution of Araneidae, including its comparison with a related family Tetragnathidae. The results obtained from 19 araneid and four tetragnathid species confirm previ- ously postulated hypothesis that the ancestral karyotype of Araneoidea (including Araneidae) consists of 24 acrocentric chromosomes in males, including two acro- centric X chromosomes of system X1X20. However, there is a tendency of 2n decrease in some araneids due to centric fusions. In these cases, centric fusions affected most autosomes (and sometimes gonosomes as well); number of chromosome pairs de- creased from 11 to six. Three independent reduction events were detected in this thesis. Furthermore, pattern of nucleolar organizer regions (NORs) was studied in this thesis using fluorescent in situ hybridization, since data on evolution of this marker are scarce in spiders. Striking variability in NORs number was discovered, ranging from one to 13 loci. Remarkably, multiple centric fusions were always ac- companied by considerable increase of NORs number. In araneids and tetragnathids possessing...

De par leur diversité de mécanismes de déterminisme du sexe et de chromosomes sexuels, les poissons téléostéens représentent d’excellents modèles pour mieux comprendre les bases moléculaires et évolutives du contrôle du développement sexuel chez les vertébrés. Grâce à l’analyse de chromosomes artificiels bactériens couvrant les chromosomes sexuels du platy Xiphophorus maculatus, trois copies d’un nouveau gène nommé teximY ont été découvertes dans la région de déterminisme du sexe du chromosome Y mais pas du chromosome X. Un gène texim1 très apparenté à teximY ainsi que trois gènes plus divergents ont été identifiés sur les autosomes. Les gènes teximY sont préférentiellement exprimés dans les testicules, au niveau des cellules germinales lors des étapes tardives de la spermatogénèse, alors que texim1 est également transcrit dans les gonades femelles. Des gènes texim ont été détectés chez d'autres poissons téléostéens mais pas chez le poisson-zèbre, ainsi que chez des céphalocordés, des urocordés et des échinodermes mais pas chez les tétrapodes. Les gènes texim codent pour des estérases putatives à domaine SGNH apparentées à des protéines cellulaires procaryotes et eucaryotes ou codées par des retrotransposons animaux. Les gènes texim sont associés à des transposons Helitron chez les poissons mais pas chez les autres animaux, suggérant capture et mobilisation du gène ancestral texim par un transposon à la base de la radiation des téléostéens. TeximY pourrait jouer un rôle dans la transposition du transposon Helitron dans la lignée germinale mâle, ou correspondre à un gène de spermatogenèse mobilisé par le transposon Helitron sur les nouveaux chromosomes sexuels de poissons. / The molecular and evolutionary basis of sex determination in vertebrates needs to be unveiled via comparison of different systems. Fish exhibit hypervariability of sex determination mechanisms. Thanks to the analysis of the Bacterial Artificial Chromosome (BAC) library covering the sex chromosomes of the platyfish Xiphophorus maculatus (Rio Jamapa population, XX /XY), three copies of a new gene have been identified in the sex-determining region of the Y but not the X chromosome, and named teximY. Four autosomal counterparts of teximY have been also detected in the genome of the platyfish with one of them, texim1 presenting 95% of cDNA sequence identity with the Y-linked copies. RT-qPCR expression analyses have been performed for each copy in male and female tissues. Two Y-linked teximY copies were preferentially expressed in testis, whereas the autosomal copy texim1 showed preferential expression in male and female gonads. In situ hybridizations with a teximY/1 probe revealed expression in late spermatids and spermatozeugmata. Texim sequences were detected in several fish species, but not in zebrafish, as well as in cephalochordates, urochordates and sea echinoderms but not in tetrapods. Predicted Texim proteins are related to proteins from different origins. Interestingly, texim genes are associated with a Helitron transposon in fish but neither in cephalochordates nor in echinoderms, suggesting capture and mobilization of an ancestral texim gene at the base of the bony fish lineage. TeximY proteins may play a role in Helitron transposition in the male germ line in fish, or texim genes are spermatogenesis genes mobilized and spread by transposable elements in fish genomes.

Cytogenetics of spiders of the infraorder Mygalomorphae is largely unknown. My thesis is focused on the karyotype evolution of spiders of families Hexathelidae Dipluridae, which are basal groups of the superfamily Avicularioidea. In this thesis the evolution of diploid chromosome number, chromosome morfology, and also sex chromosomes are studied. The karyotypes of the mygalomorphs are quite interesting for their diversity. Many members of the family Hexathelidae exhibit extreme systems of a chromosomal sex determination which are composed by many gonosomes X. The meiotic division of males is analyzed. Some species exhibit modifications of this division such as achiazmatic meiosis. Selected markers have been detected by fluorescence in situ hybridization. Keywords: evolution, fluorescent in situ hybridization, karyotype, nucleolus organizer region, sex chromosomes, spider

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No. of bitstreams: 1 gimenez_omp_dr_rcla.pdf: 25788766 bytes, checksum: da0e0599de64bcf81bfb8ddceda0c8e7 (MD5) Previous issue date: 2017-12-12 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Os cromossomos sexuais se originam independentemente de um par de homólogos autossômicos e em várias linhagens apresentam características comuns, tais como acúmulo de vários tipos de DNA repetitivo, restrição da recombinação e perda ou ganho de genes devido á diferenciação morfológica e genética entre os cromossomos sexuais X e Y ou Z e W. Estas características representam um exemplo fascinante de convergência evolutiva. Em Orthoptera, o sistema cromossômico sexual comumente encontrado na maioria das espécies estudadas é do tipo X0♂/XX♀. Entretanto, sistemas cromossômicos sexuais derivados dos tipos neo-XY♂/XX♀ e neo- X1X2Y♂/X1X1X2X2♀ são também observados, surgindo repetidamente por fusões cêntricas e em tandem, inversões e dissociações envolvendo cromossomos sexuais ancestrais e autossomos. O presente trabalho teve três objetivos. Primeiro, entender o possível papel dos DNAs repetitivos na estrutura/diversificação dos cromossomos sexuais simples e derivados, a partir do isolamento e mapeamento físico de sequências, tais como, famílias multigênicas, DNA satélite (DNAsat) e microssatélites, nas espécies Gryllus assimilis, Cycloptiloides americanus e Eneoptera surinamensis. Segundo, testar e comparar transcrição diferencial de DNAsat entre diferentes tecidos, sexos e espécies a partir de transcriptomas de Gryllus assimilis, G. bimaculatus, G. firmus e G. rubens, com o objetivo de entender os possíveis papéis funcionais destas sequências na regulação gênica, modulação da cromatina e como componentes funcionais de importantes estruturas como telômeros, centrômeros e cromossomos sexuais. Terceiro, a partir de transcriptomas de espécies de grilos (Gryllus assimilis, G. bimaculatus e G. firmus) prospectar genes codificadores de proteínas relacionados com a determinação sexual, envolvidos com o fitness reprodutivo e genes enviesados do sexo, responsáveis pelas diferenças fenotípicas entre machos e fêmeas, e tentar elucidar de uma maneira comparativa os fatores evolutivos atuando nestes loci. Origem de novo de cromossomos sexuais mediante rearranjos cromossômicos, assim como acúmulo de DNA repetitivo que levaram a diferenciação entre cromossomos sexuais são relatados em C. americanus (X1X20) e E. surianmensis (neo-X1X2Y). Estas características observadas em grilos representam outro caso notável de convergência evolutiva devido os cromossomos sexuais não relacionados compartilharem muitas propriedades entre táxons distantes. Acúmulo surpreendente de loci de DNAsat foi encontrado no neo-Y altamente diferenciado de E. surinamensis, incluindo 39 DNAsat representados em excesso neste cromossomo, que é a maior diversidade de DNAsat até agora relatada para cromossomos sexuais. Foi documentado que, particularmente os DNAsat, contribuíram grandemente para o aumento de tamanho genômico entre G. assimilis e E. surinamensis. Um achado interessante foi a identificação de DNAsat conservados entre espécies de grilos (Gryllus assimilis, G. bimaculatus e G. firmus), mas transcritos diferencialmente. Os dados relativos à presença de DNAsat no genoma de G. assimilis foram discutidos em um contexto evolutivo, com dados transcricionais permitindo comparações entre os sexos e entre os tecidos quando possível. Foram discutidas hipóteses para a conservação e transcrição de DNAsat em Gryllus, que podem resultar do seu papel na diferenciação sexual no nível da cromatina, na formação da heterocromatina e na função centromérica. Outra descoberta foi a identificação de genes determinantes do sexo e outros genes relacionados ao fitness reprodutivo, como a biossíntese de hormônios de insetos e ritmo circadiano entre espécies de Gryllus. Os efetores e os alvos downstream das vias de determinação do sexo foram previamente identificados em outros insetos, mas nunca em Orthoptera. Usando G. assimilis como modelo para estudar genes enviesados do sexo foi possível identificar um conjunto de genes altamente expressos que podem explicar diferenças fenotípicas entre os sexos. Estimou-se que os genes codificadores de proteínas relacionadas com a diferenciação sexual e com o fitness reprodutivo evoluem mais rapidamente do que os genes não reprodutivos (genes housekeeping) como resultado de uma forte seleção positiva nos primeiros. Além disso, foi encontrado que as espécies estudadas apresentam níveis excepcionalmente elevados de duplicações gênicas. As descobertas sugerem que as duplicações gênicas podem desempenhar um papel na expressão de genes enviesados do sexo no grilo de campo G. assimilis, uma espécie que no futuro provavelmente irá fornecer informações sobre genômica funcional e epigenética da determinação do sexo. / Sex chromosomes have arisen independently from an ordinary autosomal pair and in several lineages they present common characteristics, such as accumulation of distinct classes of repetitive DNAs, restriction of the recombination and loss or gain of genes due to the morphological and genetic differentiation between the sexual chromosomes X and Y or Z and W. These characteristics represent a fascinating example of evolutionary convergence. In Orthoptera, the X0♂/XX♀ sex-determining system is considered modal but eventually, diverse sex chromosome systems evolved several times, such as neo-XY♂/XX♀, X1X20♂/X1X1X2X2♀ and even neo- X1X2Y♂/X1X1X2X2♀. It was found that particularly centric fusions (i.e., Robertsonian translocations) and tandem fusions with autosomes, dissociations and inversions contributed to the formation of neo-sex chromosomes in Orthoptera. The present work had three objectives. First, get insights of the role of repetitive DNAs in the structure/diversification of simple and derivative sex-chromosomes by isolation and physical mapping of repetitive DNA sequences, such as multigene families, satellite DNA (satDNA) and microsatellites using Gryllus assimilis, Cycloptiloides americanus e Eneoptera surinamensis, as models. Second, looking at differential satDNA transcription between different tissues, sexes, and species from transcriptomes of Gryllus assimilis, G. bimaculatus, G. firmus and G. rubens, I tried to understand the possible functional roles of these sequences in gene regulation, chromatin modulation and as functional components of important structures such as telomeres, centromeres and sex chromosomes. Third, using transcriptomes from cricket species (Gryllus assimilis, G. bimaculatus and G. firmus), I searched for genes encoding proteins related to sexual determination, reproductive fitness and sex-biased genes which are responsible for the phenotypic differences between males and females. I also tried to elucidate in a comparative way the evolutionary factors acting at these loci. De novo origin of sex chromosomes by chromosomal rearrangements, as well as repetitive DNA accumulation that led to the differentiation between sex chromosomes are reported for C. americanus (X1X20) e E. surianmensis (neo-X1X2Y). These features observed in crickets represent another remarkable case of evolutionary convergence because unrelated sex chromosomes share many common properties among distant taxa. Especially astonishing accumulation of satDNAs loci was found in the highly differentiated neo-Y, including 39 satDNAs over-represented in this chromosome, which is the greatest satDNAs diversity yet reported for sex chromosomes. It has been documented that, particularly the satDNA, contributed greatly to the increase in genomic size between G. assimilis and E. surinamensis. An interesting finding was the identification of satDNA conserved among species of crickets (Gryllus assimilis, G. bimaculatus and G. firmus), but differentially transcribed. The data regarding satDNA presence in G. assimilis genome was discussed in an evolutionary context, with transcriptional data enabling comparisons between sexes and across tissues when possible. I discussed hypotheses for the conservation and transcription of satDNAs in Gryllus, which might result from their role in sexual differentiation at the chromatin level, heterochromatin formation, and centromeric function. Another finding was the identification of sex-determining genes and other genes related to reproductive fitness, such as biosynthesis of insect hormones and circadian rhythm among Gryllus species. The effectors as well as downstream targets of sex-determination pathways have been previously identified in other insects but never in Orthoptera. Using G. assimilis to study sex-biased genes I identified a set of highly expressed genes that might account for phenotypic differences between sexes. Furthermore, I estimated that proteinencoding reproductive genes evolve faster than non-reproductive genes as result of strong positive selection at those loci. It was documented that the species studied harbor exceptionally high levels of gene duplications. The findings suggest that gene duplications may play a role in sex-biased genes expression in the field cricket G. assimilis, a species likely to yield insights into the functional genomics and epigenetics of sex determination. / FAPESP: 2014/02038-8

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No. of bitstreams: 1 TeseCFY.pdf: 5114033 bytes, checksum: 6922d93e7dda82cee55aa69273fa7013 (MD5) Previous issue date: 2016-10-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Triportheus genus (Characiformes, Triportheidae) presents a particular scenario 1 in fishes, with a ZZ/ZW sex chromosomes system for all species until now investigated. The Z chromosome is metacentric and the largest one of the karyotype, remaining morphologically conserved in all species. In contrast, the W chromosome differs in shape and size among species, from almost identical to markedly reduced in size in relation to the Z, with a clear heterochromatin accumulation associated with its differentiation process. This scenario in Triportheus, along with a well defined phylogeny for this group, provided an excellent opportunity to investigate the evolutionary events associated with the sex chromosomes differentiation, a matter of increasing interest to evolutionary biology in recent years. Therefore, the purpose of this study was to investigate the origin and differentiation of sex chromosomes in eight Triportheus species, using diverse conventional and molecular cytogenetics tools, such as C-banding, chromosomal mapping of rDNAs and several other repetitive DNA sequences, comparat ive genomic hybridization (CGH), microdissection of Z and W chromosomes and whole chromosome painting (WCP). The preferential accumulation of repetitive DNAs on the W chromosome highlighted the predominant participation of these sequences in the differentiation of this chromosome. Notably, the differential accumulation of microsatellites, and a hybridization pattern with no direct correlation to the ancestry of the W chromosome, put in evidence the particular evolutionary processes that shaped the sex-specific chromosome among species. The chromosomal mapping of 5S and 18S rDNAs and U2 DNAsn highlighted a very particular scenario in the distribution of these multigene families in Triportheus. Indeed, the variability in number of the rDNA sites on the autosomes, as well as the syntenic "status" of these three multigene families, showed their intense dynamism in the karyotype evolution, revealing a much more complex organization of these genes than previously supposed for closely related species. In addition, the occurrence of U2 DNAsn on the W chromosome of T. albus appears as an evolutionary novelty, while the occurrence of 18S rDNA in the Wq terminal region of all species pointed to a conserved condition for the genus, as well as a peculiarity in the evolutionary process of the W chromosome. Noteworthy, the use of WCP, and especially CGH experiments, put in evidence sequences which are shared by both Z and W chromosomes and sequences that are unique to each one. Thus, the Wq terminal region stood out with a high concentration of female specific sequences, in coincidence with the location of the 18S rDNA genes, allowing inferences about the origin of these cistrons on the sex-specific chromosome. Our data also showed that the ZZ/ZW system had, in fact, a common origin in Triportheus, considering the homologies found in chromosomal paintings using the Z and W probes. Triportheus auritus is the direct representative of the first lineage to differentiate in the genus and WCP experiments, using the Z chromosome probe of this species, have showed how this chromosome is notably conserved in all investigated species. On the other hand, the W chromosome showed variable patterns of homology among species, highlighting the molecular divergence emerged along its evolutionary history. In conclusion, the results obtained in this study allowed to certify the common origin of the ZZ/ZW sex system in Triportheus and to evaluate the intra- and inter-specific genomic homologies and differences between the sex pair, resulting in significant advances in the knowledge of the origin and differentiation of the sex chromosomes among lower vertebrates. / O gênero Triportheus (Characiformes, Triportheidae) apresenta um cenário 1 incomum entre os peixes, com a ocorrência de um sistema de cromossomos sexuais ZZ/ZW para todas as espécies já investigadas. O cromossomo Z é metacêntrico e o maior do cariótipo, permanecendo morfologicamente conservado em todas as espécies. Contrariamente, o cromossomo W apresenta formas variáveis e tamanhos distintos entre as espécies, podendo apresentar tamanho quase idêntico ao do cromossomo Z até acentuadamente reduzido em relação a ele, com um nítido acúmulo de heterocromatina associado ao processo de diferenciação desse cromossomo. Este cenário em Triportheus, juntamente com a filogenia já bem definida para este grupo, possibilitou uma oportunidade excelente para a investigação de eventos evolutivos associados aos cromossomos sexuais, aspecto este que vem despertando interesse crescente na biologia evolutiva nos últimos anos. Assim sendo, a proposta deste estudo foi investigar a origem e a diferenciação dos cromossomos sexuais em oito espécies de Triportheus, usando ferramentas diversificadas da citogenética convencional e molecular, como o bandamento-C, mapeamento cromossômico de DNAr e diversas outras classes de DNAs repetitivos, hibridização genômica comparativa (CGH), microdissecção dos cromossomos Z e W e pintura cromossômica total (WCP). O acúmulo preferencial de várias sequências de DNAs repetitivos no cromossomo W possibilitou destacar a participação preponderante deste componente do genoma na diferenciação do cromossomo sexo18 específico. Notadamente, o acúmulo diferencial de microssatélites colocou em evidência processos evolut ivos específicos do cromossomo W entre as espécies, bem como um padrão acumulativo que não apresenta correlação direta com a ancestralidade deste cromossomo. O mapeamento cromossômico do DNAr 5S e 18S e do DNAsn U2 evidenciou um cenário bastante particular na distribuição dessas famílias multigênicas em Triportheus. A variabilidade em relação ao número de sítios de DNAr nos autossomos, assim como o “status” sintênico dessas três famílias, evidenciaram o dinamismo evolutivo desses genes mesmo entre espécies proximamente relacionadas. Além disso, a ocorrência de DNAsn U2 no cromossomo W de T. albus evidenciou uma novidade evolutiva, enquanto a ocorrência de DNAr 18S na região Wq terminal confirmou uma condição conservada no gênero, assim como uma peculiaridade do processo evolut ivo do cromossomo W, visto que todas as espécies analisadas até o momento são portadoras dessas sequências. O emprego de WCP, e principalmente de CGH, possibilitou demonstrar a localização de sequências que são compartilhadas pelos cromossomos Z e W, bem como de sequências que são exclusivas de cada um deles. Assim, a região Wq terminal se destacou por apresentar uma grande concentração de sequências específicas de fêmeas, em coincidência com a localização do cluster de DNAr 18S, possibilitando inferências sobre a origem destes cístrons no cromossomo sexo-específico. Nossos dados também demonstraram que o sistema ZZ/ZW teve, de fato, uma origem comum em Triportheus, considerando as homologias encontradas nos mapeamentos cromossômicos com sondas dos cromossomos sexuais Z e W. Triportheus auritus é a espécie representante direta da primeira linhagem a se diferenciar no gênero e experimentos de WCP, utilizando a sonda do cromossomo Z desta espécie, mostrou que este cromossomo se encontra notavelmente conservado em todas as espécies investigadas. Por outro lado, o cromossomo W apresentou padrões variáveis de homologia entre as espécies, destacando divergências moleculares diferencialmente moldadas ao longo da sua história evolutiva. Em conclusão, os resultados obtidos no presente estudo possibilitaram atestar a origem comum do sistema ZZ/ZW em Triportheus, bem como avaliar divergências e similaridades genômicas intra- e interespecíficas quanto ao par sexual, obtendo-se avanços significativos no conhecimento da origem e diferenciação dos cromossomos sexuais entre os vertebrados inferiores. / CAPES: 11744/13–8

Submitted by Aelson Maciera (aelsoncm@terra.com.br) on 2017-04-07T19:01:49Z No. of bitstreams: 1 TeseKZ.pdf: 6268573 bytes, checksum: 3d50abb73f159705b9efa45eb5cc20cf (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-04-19T17:57:39Z (GMT) No. of bitstreams: 1 TeseKZ.pdf: 6268573 bytes, checksum: 3d50abb73f159705b9efa45eb5cc20cf (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-04-19T17:57:48Z (GMT) No. of bitstreams: 1 TeseKZ.pdf: 6268573 bytes, checksum: 3d50abb73f159705b9efa45eb5cc20cf (MD5) / Made available in DSpace on 2017-04-19T18:05:13Z (GMT). No. of bitstreams: 1 TeseKZ.pdf: 6268573 bytes, checksum: 3d50abb73f159705b9efa45eb5cc20cf (MD5) Previous issue date: 2016-07-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Parodontidae is organized in three genera according to their morphological characteristics: Parodon, Saccodon and Apareiodon. The diploid number is conserved in this group with 2n=54 chromosomes, with species without heteromorphic sex chromosomes systems and other with sex chromosomes system, with female heterogamety, ZZ/ZW or ZZ/ZW1W2. Studies of chromosome localization using repetitive DNAs chromosomes of species show possible origin, differentiation and evolution of sex chromosomes in Parodontidae. However, further studies using repeats DNAs are fundamental for a better comprehension of its pathway genomic structural or functional. In this study were described the chromosome location of the (GATA)n and (TTAGGG)n sequences in eight species of Parodontidae, with aim to evaluate the probable mechanisms of chromosomal diversification, especially those related to molecular differentiation of W chromosome. Also were mapped 16 microsatellites sequences in five species of the family to check the accumulation of the repetitive DNAs in the chromosomes and verify its performance in the karyotype and sex chromosomes differentiation. Yet, partial sequences of the histone H1, H3 and H4 were determined and had chromosomal localization in six species of Parodontidae. The data show two H1 sequences in Parodontidae genomes, herein called H1 partial and H1+ ERV, in addition to partial sequences for the genes H3 and H4. The chromosomal localization of histone genes show H1, H3 and H4 in main cluster and the presence of the orphans genes for H1 + ERV. Hence, this study provide some advances in the understanding of the repetitive DNA mechanism in the karyotypic differentiation and evolution in the family Parodontidae. / Parodontidae é organizada em três gêneros agrupados de acordo com suas características morfológicas: Parodon, Saccodon e Apareiodon. O número diploide é conservado nesse grupo com 2n=54 cromossomos, com espécies sem sistemas de cromossomos sexuais heteromórficos e outras com sistemas de cromossomos sexuais do tipo ZZ/ZW ou ZZ/ZW1W2. Estudos com mapeamento de DNAs repetitivos por hibridação in situ fluorescente nos cromossomos de algumas espécies demonstraram possível origem, diferenciação e evolução dos sistemas de cromossomos sexuais desta família. No entanto, estudos mais aprofundados são fundamentais para um maior esclarecimento do papel genômico das sequências repetitivas. Neste estudo foram descritas a localização das sequências (GATA)n e (TTAGGG)n em oito espécies de Parodontidae, com o objetivo de avaliar os prováveis mecanismos de diversificação cromossômica, especialmente aqueles relacionados à diferenciação molecular do cromossomo W. Também foram mapeadas 16 sequências de microssatélites em cinco espécies da família, com objetivo de verificar o acúmulo de DNA repetitivo nos cromossomos e sua atuação na diferenciação cariotípica dos cromossomos sexuais heteromórficos. Por fim, sequências parciais das histonas H1, H3 e H4 e também dos DNAr 5S e 18S foram determinadas e tiveram sua localização cromossômica em seis espécies desta família. Com os resultados, foi possível determinar duas sequências de H1 para Parodontidae, H1 parcial e H1+ERV, além das sequências parciais para os genes H3 e H4. Todas essas análises propiciam uma melhor compreensão dos processos de diferenciação e evolução cariotípica na família Parodontidae.

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