Achalinus niger is an endemic species of Taiwan. It distributes from 1000 to 3000 m in altitude. The effect of geological isolation, especially mountains and valleys may influence the population genetic structure of the species. The ND2 gene was used as genetic marker to analyze the genetic structure of populations and phylogeography of A. niger. The mean genetic distance is 3.87¢H and the mean nucleotide diversity 3.5¢H. The Meifeng population was distinct in genetic structure from other populations. The data suggest that A. niger had more than one incursion events. In phylogenetic analyses, there were three major lineages in A. niger, and these lineages were correlated to geographic distribution. Lineage¢¹ was sampled from northern Taiwan, lineage¢º from southern Taiwan, while lineage ¢» from Meifeng only. The result of AMOVA indicated that there were high genetic variations among groups. The genetic isolation and geographic distribution of these groups probably resulted from the geographic barriers.

The endemic wildflower, Geleznowia verrucosa Turcz. (Rutaceae), is widely distributed as small disjunct populations throughout the sandplains of Western Australia (21 degrees 50'S, 116 degrees 12'E to 31 degrees 12'S, 117 degrees 02'E). Although the morphological forms can be genus is supposedly monospecific, three recognised in the field:(1) a small form (0.5-1 m) with small, often solitary flowers and small leaves;(2) a large form (1-2 m) with larger, more abundant flowers and larger leaves; and,(3) an intermediate form exhibiting mixed morphological characters.The patterns of morphological, reproductive and genetic variation within and between populations of these three forms were investigated. Uni- and multivariate analyses of morphological traits found the large and intermediate forms to be closely allied, and distinguishable from the small form. Responses to controlled pollination experiments indicated that the small form favours selfing but maintains some level of outcrossing, while the large form exhibits a mixed mating system. The intermediate form displays a stronger self-pollination mechanism than the small form.Patterns of genetic variation were analysed using both allozymes and randomly amplified polymorphic DNA (RAPDs). The allozyme analysis concurred with genetically depauperate expectations of endemic taxa (A, 1.4; P, 29.6%; H(subscript)0, 0.055; H(subscript)e, 0.097). Genetic diversity and patterns of allelic distribution, however, differed within the three forms. Lower levels of genetic diversity were found in the small form (H(subscript)T,0.192) compared with the large form (H(subscript)T, 0.254), although both forms apportioned this diversity within populations (H(subscript)S, 0.122 and 0.164, respectively) rather than between D(subscript)ST, 0.070 and 0.090, respectively). In contrast, populations of the intermediate form are highly divergent ++ / (G(subscript)ST, 54%), with genetic diversity apportioned between populations (D(subscript)ST, 0.121) rather than within (H(subscript)S, 0.105). Whereas the morphometric analyses had indicated closer affinity between the large and intermediate forms, both allozyme and RAPD analyses suggested that the intermediate form is closer to the small form than to the large form.There is circumstantial evidence to suggest that the intermediate form has arisen following hybridisation between the small and large forms. Its hybrid origin is supported by the high level of genetic diversity between the intermediate form populations, as well as its strong autogamous tendencies and mixed morphological characteristics. In a putative zone of hybridisation between the small and large forms, asymmetric introgression was observed, indicating gene exchange between the two forms can occur when they come into contact.It is speculated that three major events have shaped the evolution of Geleznowia verrucosa and contributed to hybridisation between the small and large forms. Firstly, the small form is derived from the large form; associated with this speciation was a shift in reproductive strategy from outcrossing to selfing when the small form migrated into a harsher and more unpredictable environment. Secondly, recurrent Tertiary and Quaternary climatic perturbations have facilitated range expansion and contraction of these forms, generating opportunities for spatially and temporally distributed hybridisation events. Finally, more recent evolution has been driven by population disjunction, limited gene flow, and bottleneck and/or associated founder effects.From this study it is apparent that the genus Geleznowia consists of at least two taxa and a series of hybrid derivatives. On this basis, formal systematic revision of the genus is now warranted. Systematic clarification will also assist ++ / with the conservation and management of this valuable natural resource, which is currently under threat.

Understanding the factors and processes that influence intraspecific genetic variation are essential to better understand evolutionary processes. In this research, I examined patterns of gene flow and their effects on the distribution of genetic variation and spatial genetic structuring at different spatial scales. I used a combination of population genetics, spatial analysis, morphometrics and phylogeography in order to understand the patterns of genetic variation and their resulting phenotypic variations in a semi-aquatic species, the muskrat (Ondatra zibethicus).

Orientador: Vera Nisaka Solferini / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T00:56:04Z (GMT). No. of bitstreams: 1 Salloum_PriscilaMadi_M.pdf: 769704 bytes, checksum: d9254ea3504160fbbd563282b7d46eb7 (MD5) Previous issue date: 2015 / Resumo: A estrutura genética de populações marinhas pode ser avaliada de dois modos: espacial e temporal. Nesse ambiente, fatores diferentes funcionam como barreiras ao fluxo gênico para espécies distintas, apesar da expectativa de que animais com grande capacidade de dispersão apresentem populações panmíticas ao longo de sua distribuição. Echinolittorina lineolata (D¿Orbigny 1840) é um gastrópode comum na costa brasileira e que apresenta larvas com elevada capacidade de dispersão, sendo um interessante modelo para avaliar estrutura genética em ambiente marinho. Este trabalho utilizou abordagens espacial e temporal para avaliar a variabilidade genética e a estrutura populacional de E. lineolata em duas praias do estado de São Paulo. Quatro coletas de juvenis dessa espécie foram feitas em intervalos de 40 dias; três regiões do DNA mitocondrial foram utilizadas como marcadores moleculares, sendo duas regiões do gene citocromo-b (Cyt-b) e uma do gene citocromo oxidase I (CO-1). Os índices de diversidade haplotípica e nucleotídica foram baixos, o que é semelhante a outras espécies marinhas. Redes de haplótipo, análises de variância molecular e a estatística FST evidenciaram estrutura genética entre amostras das duas praias (espacial) e entre amostras das quatro coletas (temporal). Dois fatores foram considerados como prováveis geradores da estrutura genética observada nesses juvenis de E. lineolata: variações geográficas ou oceanográficas locais e variância no sucesso reprodutivo / Abstract: The genetic structure of marine populations can be evaluated by two modes: spatial and temporal. In this environment, different factors work as barriers to gene flow for different species, although animals with high dispersal ability are expected to present panmitic populations along their range. Echinolittorina lineolata (D¿Orbigny 1840) is a common gastropod on the Brazilian coast and has larvae with high dispersal ability, being an interesting model to evaluate genetic structure in the marine environment. This work used spatial and temporal approaches to evaluate the genetic variability and population structure of E lineolata in two beaches of the São Paulo state. Four collections of juveniles were done in 40-days intervals; three regions of the mitochondrial DNA were used as molecular markers: two from cytochrome-b gene (Cyt-b) and one from cytochrome oxidase I gene (CO-1). The haplotype and nucleotide diversity indexes were low, similar to other species. Haplotype networks, analyses of molecular variance and FST statistics indicated genetic structure among the two beaches¿ samples (spatial) and among the four collections¿ samples (temporal). Two factors were considered as likely drivers of the observed genetic structure on these juveniles: local geographic or oceanographic variations and variance in the reproductive success / Mestrado / Genetica Animal e Evolução / Mestra em Genética e Biologia Molecular

Local factors have the potential to generate genetic structure within species if populations respond differently to varying environmental conditions across their geographic range. In this project, spatial genetic structure was examined in the legume, Chamaecrista fasciculata, its symbiotic nitrogen fixing bacteria, and rhizosphere microbiomes. In the first chapter, the aim was to test for genetic structure among populations of C. fasciculata in the Southeast and to evaluate whether phenotypic variation in leaf pubescence is associated with genetic divergence among populations, which would be consistent with local adaptation. My results did not detect a significant association between genetic structure and phenotypic variation in leaf pubescence, but the role of environmental variables in generating the observed patterns of spatial genetic variation in C. fasciculata was demonstrated. In the second project, I analyzed genetic structure within a single population to test for the presence of fine-scale genetic structure of the host plant and to determine if genetic structure of symbiotic nitrogenixing rhizobia is influenced by host plants. Neighboring plants are expected to be more genetically similar than distant plants. If this expectation is supported and genotype x genotype interactions are important in this system, then I anticipated that spatially close host plants would show more genetically similar microbiota in their nodules and rhizospheric soil than distant host plants. The results indicated fine-scale genetic structure for both host plants and nodulating rhizobia, suggesting that the both organisms are influenced by similar mechanisms structuring genetic diversity or shared habitat preferences. In the third project, I characterized fine-scale structure and diversity of microbial communities of the rhizosphere of host plants within a single population. The results revealed significant differences in bacterial and fungal communities among host plants and a significant association between genetic distance of both microbial communities and spatial and plant genetic distances. These data confirm the importance of plant genotype and physical distance in shaping the genetic structure and diversity of bacterial and fungal communities of the rhizosphere. Overall, this study enhances our understanding of the degree to which intraspecific genetic variation in plants influences the diversity and structure of soil microbial communities.

Diploma thesis deals with genetic variability and evolutionary relationships among selected species of the group Chenopodium album and is especially focused on the origin of hexaploid species C. album in the Czech Republic. The main aim of the study was detection of putative recent emergence of hexaploid C. album s. str. in mixed populations of diploid (C. ficifolium and C. suecicum) and tetraploid (C. strictum and C. striatiforme) species. To assess phylogenetical relationships I performed an analysis of nuclear microsatellite loci, that are suitable for detection parental lines within polyploid species. As long as microsatellite primers have been developed for studied group, therefore they had to be cross-amplified from closely related species C. quinoa. Three PCR multiplexes were assembled by cross-amplification of microsatellite primers. These PCR multiplexes were tested on representative sample sets to estimate genetic variability of individual microsatellite loci. A total of 911 individuals were analyzed from five localities from the Czech Republic. The results of analyses revealed (1) high interspecific differentiation, (2) gene flow among species of the same ploidy levels, (3) presence of hybrids among diploid species of C. ficifolium and C. suecium as well as among tetraploid species C. strictum...

Individual costs and benefits of living in groups vary with group size, stability, and composition. Investigations of these features of group living have lead to the recognition of a variety of social structures. Although many studies have examined social structure in animals with long-term, stable groups, little is known about groups with highly variable group size and composition, such as fission-fusion dynamics. In this thesis I examined the causes and consequences of fission-fusion dynamics by exploring the socioecology of female northern long-eared bats, Myotis septentrionalis. Like many temperate bats, female northern long-eared bats show natal philopatry to summer areas. During this time, they live in groups with fission-fusion dynamics as individuals move among a network of roosts and roost-groups. To examine the causes of fission-fusion dynamics, I examined why females switch roosts. To address the consequences of these dynamics, I asked whether females could form stable relationships, and what factors might explain these relationships. I was able to identify the possible causes and consequences of fission-fusion dynamics that had not yet been explored in bats. I demonstrated that fission-fusion dynamics may be explained, at least in part, by changes in ambient conditions that prompt frequent roost-switching. Despite the highly dynamic nature of these groups, females formed long-term social relationships that were based in part on age and genetic relatedness. These findings have potential consequences for the evolution of social behaviour within groups, such as cooperation and nepotism. My work also raised several questions that require further examination to fully understand the evolution of fission-fusion dynamics. For example, the question remains whether species or sympatric groups of conspecifics with different degrees of roost-switching show the same social structure. By answering these questions, we can gain a better understanding of the causes and consequences of fission-fusion dynamics across species of bats. Once this is achieved, we can then look for parallels with other taxa to answer questions about the evolution of these dynamic systems.

Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Deciphering patterns of intraspecies population genetic structuring in commercially important shark species is essential for an integrated fisheries management approach to conservation of regional biodiversity. The common smoothhound shark, Mustelus mustelus, is an overexploited, commercially and recreationally important shark species in South Africa. Considering the vulnerable status of the common smoothhound shark and due to very limited available genetic information, this study aimed to develop molecular markers, assess patterns of genetic diversity and population connectivity along the South African coast using multilocus data generated from 12 microsatellite markers and the mitochondrial gene, NADH dehydrogenase subunit 4 (ND4). The cross-species amplification of microsatellites proved useful for genetic diversity and population genetic analysis of the common smoothhound shark. These microsatellites could aid in the molecular characterisation of other endemic and cosmopolitan species and provide valuable tools for the conservation of potentially threatened or exploited shark species. For the microsatellite data, moderate levels of genetic diversity based on the heterozygosity, allelic richness and haplotype diversity were found in a total of 144 individuals sampled across eight study populations. Estimates for pairwise population differentiation, F-statistics, AMOVA and factorial correspondence analysis (FCA) indicated significant genetic structure within and between west- and east coast populations. Additionally, Bayesian clustering analyses detected two putative ancestral gene pools, supporting the presence of a biogeographic barrier at the Cape Agulhas region and therefore genetic discontinuity between the Indian and Atlantic Ocean samples. On the contrary, mitochondrial data indicated that common smoothhound shark is genetically homogenous with substantial interoceanic gene flow. Such conflicting signals found between nuclear and mitochondrial DNA (mitonuclear discordance) can be attributed to a number of factors and could simply be due to the inherent differences in marker properties or an indication of sex biased dispersal. Despite an indication of an expanding common smoothhound shark population based on both marker types, a contemporary genetic bottleneck may have gone undetected as genetic divergence was very low in some of the study populations. Nonetheless, contemporary restriction to gene flow and historical demographics such as range expansion are proposed as the most likely forces explaining genetic structure in present-day common smoothhound sharks in South Africa. For future sustainable exploitation of common smoothhound shark, the possible existence of two genetically differentiated populations and observed asymmetric gene flow along the South African coast should be taken into consideration. It is also recommended that in the future further evaluations of finescale genetic structure and seasonal migration patterns in this commercially important species are conducted in order to allow integration of this knowledge into existing fisheries management practices. / AFRIKAANSE OPSOMMING: Die ontsyfering van patrone van intraspesie populasie genetiese struktuur in kommersieel belangrike haai spesies is noodsaaklik vir 'n geïntegreerde bestuursbenadering tot visserue en bewaring van plaaslike biodiversiteit. Die hondhaai, Mustelus mustelus, is 'n oorbenutte, kommersiële en sporthengelary belangrike haai spesie in Suid-Afrika. Met inagneming van die kwesbare status van die hondhaai en as gevolg van baie beperkte beskikbare genetiese inligting, het hierdie studie gepoog om molekulêre merkers te ontwikkel, asook om die patrone van genetiese diversiteit en populasie struktuur te ondersoek langs die Suid- Afrikaanse kus deur middel van multilokus data gegenereer uit 12 mikrosatelliet merkers en die mitokondriale geen, NADH dehidrogenase subeenheid 4 (ND4). Die kruis-spesie amplifisering van mikrosatelliete was nuttig vir genetiese diversiteit en populasie genetiese analise van die hondhaai. Hierdie mikrosatelliete kan moontlik help met die molekulêre karakterisering in ander inheemse en kosmopolitaanse spesies en kan as waardevolle hulpmiddels dien in die bewaring van potensieel bedreigde en oorbenutte haai spesies. Vir die mikrosatelliet data is matige vlakke van genetiese diversiteit gevind gebaseer op heterosigositeit, alleliese rykheid en haplotipe diversiteit gevind in 'n totaal van 144 individue getoets oor agt studie populasies. Skattings vir paarsgewyse populasie differensiasie, Fstatistieke, AMOVA en faktoriale ooreenstemming analise het betekenisvolle genetiese struktuur aangedui binne en tussen wes- en ooskus populasies. Daarbenewens, het Bayesian groepering analise twee potensiele voorvaderlike geenpoele waargeneem, ter ondersteuning van die teenwoordigheid van 'n biogeografiese versperring by die Cape Agulhas gebied en dus genetiese diskontinuïteit tussen die Indiese en Atlantiese Oseaan monsters. In teenstelling het die mitokondriale data aangedui dat hierdie haai spesie geneties homogeen is met aansienlike interoseaniese geenvloei. Sulke teenstrydige tekens tussen kern en mitokondriale DNS (mitokern onenigheid) kan toegeskryf word aan 'n aantal faktore en kan eenvoudig wees as gevolg van die inherente verskille in merker eienskappe of 'n aanduiding van geslags sydigeverspreiding. Ten spyte van 'n aanduiding van 'n groeiende hondhaai populasie gebaseer op beide merker tipes, kon 'n hedendaagse genetiese bottelnek onopgemerk gegaan het aangesien genetiese divergensie baie laag was in sommige van die studie populasies. Nietemin, hedendaagse restriksie van geenvloei en historiese demografie soos verbreding van reeks voorkoming word voorgestel as die mees waarskynlike dryfkragte wat genetiese struktuur in die hedendaagse hondhaaie in Suid-Afrika verduidelik. Vir toekomstige volhoubare benutting van die spesie, moet die moontlike bestaan van twee geneties verskillende populasies en waargenome asimmetriese geenvloei langs die Suid-Afrikaanse kus in ag geneem word. Vir die toekoms word dit ook aanbeveel dat verdere evaluerings van fyn-skaal genetiese struktuur en seisoenale migrasie patrone in hierdie kommersiël belangrike spesie uitgevoer word om die integrasie van hierdie kennis in die bestaande bestuur van visserye praktyke toe te laat. / National Research Foundation (NRF)

Submitted by Baltasar Fernandes Garcia Neto null (baltasar.fgn@gmail.com) on 2018-03-09T19:05:14Z No. of bitstreams: 1 Diss_Balt_Final.pdf: 637437 bytes, checksum: 99a5603df788f9d4cb2c007a3e8180fd (MD5) / Approved for entry into archive by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br) on 2018-03-12T18:40:44Z (GMT) No. of bitstreams: 1 garcianeto_bf_me_jabo.pdf: 637437 bytes, checksum: 99a5603df788f9d4cb2c007a3e8180fd (MD5) / Made available in DSpace on 2018-03-12T18:40:44Z (GMT). No. of bitstreams: 1 garcianeto_bf_me_jabo.pdf: 637437 bytes, checksum: 99a5603df788f9d4cb2c007a3e8180fd (MD5) Previous issue date: 2018-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A complexidade das características que podem apresentar diferentes estruturas de ação gênica como, por exemplo, poligênicas ou afetadas por genes de efeito maior, aliado a diferentes herdabilidades, entre outros fatores, tornam a detecção de QTLs desafiadora. Diversos métodos têm sido empregados com o intuito de realizar estudos de associação ampla do genoma (GWAS), objetivando o mapeamento de QTL. A metodologia weighted single-step GBLUP (wssGBLUP), por exemplo, é uma alternativa para a realização de GWAS, que permite o uso simultâneo de informações genotípicas, de pedigree e fenotípicas, mesmo de animais não genotipados. Métodos Bayesianos também são utilizados para a realização de GWAS, partindo da premissa básica de que a variância observada pode variar em cada locus em uma distribuição a priori específica. O objetivo do presente estudo foi avaliar, por meio de simulações, quais métodos, dentre os avaliados, mais auxiliaria na identificação de QTLs para características poligênicas e afetadas por genes de efeito maior, apresentando diferentes herdabilidades. Utilizamos os métodos: wssGBLUP, com a inclusão ou não de informação adicional fenotípica de animais não genotipados e dois distintos ponderadores para os marcadores, onde w1 representou a mesma ponderação (w1=1) e w2 a ponderação calculada de acordo com o processo de iteração anterior (w1) ; Bayes C, assumindo dois valores para π (π=0.99 and π=0.999), onde π é a proporção de SNPs não incluída no modelo, além do LASSO Bayesiano. Os resultados mostraram que para cenários poligênicos o poder de detecção é menor e o uso adicional de fenótipos de animais não genotipados pode ajudar na detecção, ainda que com pouca intensidade. Para cenários com característica sob efeito maior, houve maior poder na detecção de QTL pelos diferentes métodos em comparação aos cenários poligênicos com destaque para a leve vantagem do método Bayes C. A inclusão de informação fenotípica adicional, entretanto, causou viés nas estimativas e atrapalhou o desempenho do wssGBLUP na presença de QTL com efeito maior. O aumento da v herdabilidade para ambas as estruturas melhorou o desempenho dos métodos e o poder de mapeamento. O método mais adequado para a detecção de QTL depende da estrutura genética e da herdabilidade da característica, não existindo um método que seja superior para todos os cenários. / The complexity of the traits that can present different genetic structures, such as polygenic or affected by genes of major effect, in addition to different heritabilities, among other factors, make the detection of QTLs challenging. Several methods have been employed with the purpose of performing genome wide association studies (GWAS), aiming the mapping of QTL. The single-step weighted GBLUP (wssGBLUP) method, for example, is an alternative to GWAS, which allows the simultaneous use of genotypic, pedigree and phenotypic information, even from non-genotyped animals. Bayesian methods are also used to perform GWAS, starting from the basic premise that the observed variance can vary at each locus with a specific priori distribution. The objective of the present study was to evaluate, through simulation, which methods, among the evaluated ones, more assist in the identification of QTLs for polygenic and major gene affected traits, presenting different heritabilities. We used the following methods: wssGBLUP, with or without additional phenotypic information from non-genotyped animals and two different weights for markers, where w1 represented the same weight (w1=1) and w2 the weight calculated according to the previous iteration process (w1); Bayes C, assuming two values for π (π = 0.99 and π = 0.999), where π is the proportion of SNPs not included in the model, and Bayesian LASSO. The results showed that for polygenic scenarios the detection power is lower and the additional use of phenotypes from non-genotyped animals may help in the detection, yet with low intensity. For scenarios with major effect, there was greater power in the detection of QTL by all different methods with slighter superior performance for the Bayes C method. However, the inclusion of additional phenotypic information caused bias in the estimates and harmed the performance of the wssGBLUP in the presence of major QTL. The increase in heritability for both structures improved the performance of the methods and the power of mapping. The most suitable method for the iii detection of QTL is dependent on the genetic structure and the heritability of the trait, and there is not a superior method for all scenarios.

Resumo: O presente trabalho teve como objetivo principal ampliar o conhecimento sobre a estrutura genética e obter informações para a conservação de pacu (Piaractus mesopotamicus Holmberg, 1887), provenientes de populações selvagens dos rios da Bacia do Alto Paraguai. Esta espécie possui grande valor comercial e imenso potencial para exploração em pisciculturas. Os marcadores moleculares do tipo microssatélite utilizados neste estudo, resultaram em muitas informações sobre a estrutura populacional desta espécie, permitindo uma possível caracterização dos bancos genéticos para esta espécie. Exemplares provenientes de nove sub-bacias do Pantanal Matogrossense foram coletados para a realização da extração de DNA visando à análise do material genômico. Para isto, foram retirados pequenos fragmentos de nadadeira de cada indivíduo. A amplificação dos locos microssatélites foi realizada num termociclador de PCR utilizando oligonucleotídeos marcados com fluorescência, conforme descrito na literatura. A genotipagem foi realizada no seqüenciador automático MegaBACETM 1000 (Amersham Biosciences), pertencente ao Centro de Estudos do Genoma Humano da Universidade de São Paulo. Os tamanhos dos alelos obtidos foram organizados para a montagem das matrizes de dados que foram submetidas aos programas computacionais para verificar a variabilidade genética nas populações. Os parâmetros que permitiram a determinação da diversidade genética intra e interpopulacional foram o número de alelos por loco, riqueza alélica, heterozigosidade observada e esperada, equilíbrio de Hardy Weinberg, índices Fst e Rst, análise de variância molecular (AMOVA), índice de fixação, desequilíbrio de ligacão e o número de migrantes. Também foi feita uma análise bayesiana para verificar a estrutura populacional e um dendrograma foi gerado a partir da matriz de distância baseada... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work aimed to obtain information about the genetic structure of pacu (Piaractus mesopotamicus Holmberg, 1887), from wild populations of Alto Paraguai Basin Rivers. This specie has a greatly commercial importance, with huge potential for hatcheries. The pacu has a wide distribution in the Prata Basin, formed by Paraguay, Paraná and Uruguay rivers and their tributaries Microsatellites markers offer relevant information about this specie, allowing the characterization of genetic stocks. Individuals from nine sampling sites in the Pantanal Matogrossense were analysed in this study. DNA extraction methods did not required killing the samples, we used fin clippings from each individual. The amplification of microsatellites loci was carried out via polymerase chain reaction (PCR) using oligonucleotide marked with fluorescent labels. The amplified fragments were analysed on the automatic DNA sequencer MegaBACETM 1000 (Amersham Biosciences), belonged to Centro de Estudos do Genoma Humano from Universidade de São Paulo. Allele sizes were organized in an input file that was submitted statistical analysis to verify the genetic variability of populations. The parameters used to estimate the genetic diversity intra and interpoulation were number of allele per locus, allele richness, observed and expected heterozygosities, Hardy Weinberg equilibrium, molecular variance analyses (AMOVA), fixation index, linkage disequilibrium and gene flow. Bayesian estimates were used to verify the populacional structure and a dendogram was calculated by the distances matrix based on chord distances values. The results showed no population structuring and intense gene flow. The most probable causes are the hight migratory capacityof this fish and the climatic and geographic characteristics of the Pantanal Matogrossense. / Orientador: Fausto Foresti / Coorientador: Daniela Calcagnotto / Banca: Alexandre Wagner Silva Hilsdorf / Banca: Emiko Kawakami de Resende / Banca: Jeffrey Frederico Lui / Banca: Claudio de Oliveira / Doutor