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Cette thèse a pour objet l'étude des patrons de biodiversité et des processus qui la soustendent au sein d'un écosystème marin remarquable : les forêts de laminaires. L'originalité de ce travail a été de caractériser les variations spatio-temporelles de la biodiversité conjointement à deux niveaux de diversité intra et inter-spécifique. La diversité génétique des populations des deux espèces soeurs Laminaria digitata et Laminaria hyperborea, et la diversité spécifique des macroalgues vivant sous leur canopée ont été étudiées à l'échelle de la Bretagne, dans l'espace, à différents niveaux hiérarchiques (sur 500 km de côte), et dans le temps, à l'échelle des saisons et des deux dernières décennies. Les résultats obtenus révèlent que les populations de L. digitata, occupant la marge inférieure de l'intertidal, sont moins diverses et plus structurées que celles de l'espèce subtidale : L. hyperborea. De la même manière, les communautés algales en sous strate de L. digitata sont moins diverses et plus structurées que celles associées à L. hyperborea. Ces deux observations s'expliqueraient en partie par une dispersion plus importante en zone subtidale qu'en zone intertidale. Nos résultats démontrent qu'à l'échelle du littoral breton, il existe une mosaïque de conditions abiotiques avec des caractéristiques spatio-temporelles contrastées, et que cette variabilité permet d'expliquer certaines différences dans les patrons de diversité. Ainsi, les deux régions de la baie de Morlaix et de la mer d'Iroise forment " une poche d'eau froide " caractérisée par une faible amplitude des températures à la fois saisonnières et annuelles et apparaissent comme relativement peu impactées par le changement global par rapport aux autres régions étudiées. Les niveaux de diversité et de connectivité y sont forts aussi bien pour les mesures de diversités intra et inter-spécifiques et pour les deux espèces cibles. Inversement, la baie de St Malo, montre les niveaux de diversités et de connectivités génétique et spécifique les plus faibles aussi bien pour L. digitata que pour L. hyperborea alors que c'est la région étudiée qui révèle les plus fortes amplitudes saisonnières de températures des eaux de surface, cette variabilité s'accentuant nettement au cours des deux dernières décennies. Les patrons de diversités en Bretagne Sud, où les eaux sont les plus chaudes, diffèrent selon l'espèce cible (L. digitata s'y trouve en limite d'aire) et/ou le niveau de diversité considéré. En conclusion, nos résultats montrent qu'il existe une mosaïque d'environnements différents à une échelle spatiale (10 à 250 km) qui n'est souvent pas prise en compte dans les modèles de niches écologiques prédisant les changements de biodiversité. De plus, les corrélations entre les patrons spatiaux de diversité génétique et spécifique (SGDC) sont généralement positives, bien que leur force et leur significativité varient dans l'espace et/ou selon l'espèce cible considérée.

Understanding the events and processes responsible for patterns of within species diversity, provides insight into major evolutionary themes like adaptation, species distributions, and ultimately speciation itself. Here, I combine ecological, genetic and spatial perspectives to evaluate the roles that both historical and contemporary factors have played in shaping the population structure and genetic variation of foxsnakes (Pantherophis gloydi). First, I determine the likely impact of habitat loss on population distribution, through radio-telemetry (32 individuals) at two locations varying in habitat patch size. As predicted, individuals had similar habitat use patterns, but restricted movements to patches of suitable habitat at the more disturbed site. Also, occurrence records spread across a fragmented region were non-randomly distributed and located close to patches of usable habitat, suggesting habitat distribution limits population distribution. Next, I combined habitat suitability modeling with population genetics (589 individuals, 12 microsatellite loci) to infer how foxsnakes disperse through a mosaic of natural and altered landscape features. Boundary regions between genetic clusters were comprised of low suitability habitat (e.g. agricultural fields). Island populations were grouped into a single genetic cluster suggesting open water presents less of a barrier than non-suitable terrestrial habitat. Isolation by distance models had a stronger correlation with genetic data when including resistance values derived from habitat suitability maps, suggesting habitat degradation limits dispersal for foxsnakes. At larger temporal and spatial scales I quantified patterns of genetic diversity and population structure using mitochondrial (101 cytochrome b sequences) and microsatellite (816 individuals, 12 loci) DNA and used Approximate Bayesian computation to test competing models of demographic history. Supporting my predictions, I found models with populations which have undergone population size drops and splitting events continually had more support than models with small founding populations expanding to stable populations. Based on timing, the most likely cause was the cooling of temperatures and infilling of deciduous forest since the Hypisthermal. On a smaller scale, evidence suggested anthropogenic habitat loss has caused further decline and fragmentation. Mitochondrial DNA structure did not correspond to fragmented populations and the majority of foxsnakes had an identical haplotype, suggesting a past bottleneck or selective sweep. / Thesis (Ph.D, Biology) -- Queen's University, 2011-01-11 10:40:52.476

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

In this thesis we have addressed three different although related topics. First, we studied the post-mortem mutation damage rate of contaminated DNA sequences in ancient human remains focusing on the development of strategies to avoid pre-laboratory derived contaminations. We proposed a guideline to control them consisting in typing every single person involved on the manipulation of the remains, especially when they have not been excavated and washed under controlled conditions. Second, we successfully develop a non-invasive technique to sequence ancient remains but preserving it from the destruction. And third, we sequenced ancient human remains from different evolutionary times (from Paleolithic to post-Neolithic) to make inferences about the peopling of Western Europe focusing mainly in the Iberia peninsula. We found that there is a long term genetic continuity at least since the Neolithic. The only clear genetic discontinuity found is that involving two different human species, H. sapiens and H. neanderthalensis. / En la presente tesis hemos tratado tres temas diferentes aunque muy relacionados. Primero, hemos estudiado la tasa de mutación post-mortem de secuencias de ADN contaminante en restos humanos antiguos centrándonos en el desarrollo de estrategias para evitar que las muestras se contaminen antes de llegar al laboratorio. Proponemos una guía que consiste en el tipado genético de cada persona implicada en la manipulación de los restos, especialmente cuando estos han sido excavados y lavados bajo condiciones no controladas. Segundo, hemos desarrollado una técnica no invasiva para secuenciar DNA de restos humanos antiguos pero sin destruirlos. Y por ultimo, hemos secuenciado restos humanos antiguos pertenecientes a diferentes periodos evolutivos (desde el Paleolitico hasta el post-Neolitico) que nos han permitido hacer inferencias sobre el poblamiento Europeo centrándonos básicamente en la Península Ibérica. Hemos encontrado que ha habido una continuidad genética desde el Neolítico. La única clara discontinuidad genética encontrada es entre dos especies distintas: H. Sapiens y H.neanderthalensis.

Rising archipelagos provide unique settings for the study of the temporal and spatial dynamics of their biota. This offers the possibility to study the ecology and genetics of early successional processes; both between islands that differ in age and within islands when already established organisms have to keep pace with the changing environment. I have worked in the Skeppsvik Archipelago housing about 100 islands that due to land uplift vary in age, thus representing various stages of primary succession. I have utilized a naturally created metapopulation of Silene dioica, which in this archipelago is a dominant plant of the deciduous border, offering the possibility to study subpopulations on islands of different ages and in different phases of primary succession. Many plant species exist as metapopulations, which consists of many local populations which may differ in size and degree of connectivity. Metapopulations are further characterized by recurrent colorizations and extinctions of local populations, meaning that a species continually must disperse and relocate to allow for persistence in this system. For a dioecious plant species, gene flow is in the shape of seeds and pollen and to allow for the persistence of populations, it is necessary that levels of seed dispersal and pollen gene flow are enough to ensure both colonisation, establishment and subsequent population growth. Levels of seed dispersal and pollen gene flow is in turn influenced by how the two sexes partition resources between reproduction, growth and survival. In paper I, I combined a field survey, a common garden experiment and a nine-year demographic study to assess the demographic consequences of sex-specific resource allocation and to investigate if differential costs of reproduction may be a driver in the evolution of sexual dimorphism in dioecious Silene dioica. Significant somatic intersexual dimorphism was found with females being the larger sex, both in terms of above – and belowground biomass. Furthermore, the reproductive effort of females exceeds that of males across a growing season which largely confirms what has been observed earlier in dioecious, herbaceous plant species. According to the cost of reproduction hypothesis, high reproductive investment should result in trade-offs with somatic and/or life-history traits. Somatic trade-offs were not observed, and instead I found strong, positive associations between reproductive investment and vegetative growth in both males and females. Compensation mechanisms were found in both sexes although females are generally more efficient at compensating their reproductive costs. At the end of a flowering season, after having paid the current costs of reproduction, females are better than males at provisioning perennial roots and rosettes potentially influencing the ability to set future flower buds and winter survival. Trade-offs were found between current and future reproduction and survival, but this is condition dependent and compensation through frequency of flowering plays an important role. The cost of reproduction hypothesis appears to play some role in driving the somatic and demographic sexual dimorphisms observed in this system but sexual selection acting on males will be a fruitful avenue for future research. In paper II, I investigated the population genetic consequences of metapopulation dynamics in Silene dioica. The occurrence of islands in different phases of primary succession together with successional gradients across islands, makes it possible to investigate the genetic dynamics occurring in an age-structured metapopulation across several hierarchical levels. Genetic diversity and differentiation were estimated in eight young, recently colonised populations and in ten populations of an intermediate successional stage. Young populations were less genetically diverse compared to older populations, indicating that bottlenecks, created by small founding groups derived from a limited number of source populations, reduce the genetic diversity within newly founded populations. The observation of strong genetic structure both between islands and between patches with islands, indicates that gene flow is restricted across several spatial levels in this system. However, the lack of statistically significant differences in genetic differentiation between young and intermediate populations, indicates that levels of gene flow may not be high enough to reduce the genetic differentiation that arise from the initial founder event. The patterns of sexual dimorphism and the roles of males and females in Silene dioica have evolved to allow persistence in an ecological and population context of this species. The nature of this habitat, where islands rise up from the sea creating new environments for colonisation while at the same time, autogenic primary succession processes eventually leads to extinction, means that S. dioica continuously must relocate within successional phases for its persistence. The obvious success of this dioecious plant is apparent as it is one of the few dominant species in the deciduous border. This suggests that levels of seed dispersal and gene flow are sufficient enough to allow for establishment and persistence of island populations and that the sexual dimorphisms that have evolved in this metapopulation system act to increase levels of gene flow. The "live hard – die young" strategy, with extensive flowering bouts, which we find in the males may have evolved as a way of maintaining sufficient levels of genetic diversity in the metapopulation but will only be a possible strategy if there are continuous opportunities for re-establishments. Thus, the continuous land uplift that is occurring in the northern part of the Gulf of Bothnia may very well be a prerequisite for the long-term persistence of this dioecious, perennial plant species. / Landhöjningsprocesser i skärgårdsmiljöer skapar nya habitat som gör det möjligt att studera naturliga populationer i ett rumsligt och tidsmässigt sammanhang. Detta möjliggör studier av ekologi och genetik i tidiga successionsprocesser, både mellan öar som skiljer sig åt åldersmässigt och inom öar, där redan etablerade organismer måste anpassa sig till en föränderlig miljö. Jag har utfört studier i Skeppsviks skärgård som rymmer cirka 100 öar. På grund av landhöjningen så varierar dessa öar i ålder och de representerar således olika stadier i primärsuccession. Jag har använt mig av en naturlig Silene dioica metapopulation lokaliserad i Skeppsviks skärgård. Många växtarter existerar i metapopulationer, vilket består av ett antal lokala populationer som kan skilja sig åt i storlek och grad av anknytning. Metapopulationer kännetecknas även av återkommande koloniseringar och utrotningar av lokala populationer, vilket innebär att en art kontinuerligt måste sprida sig för att garantera sin fortlevnad i detta system. Genflöde inom dioika växtarter är i form av pollen och frön, och för att populationer skall kunna överleva så är det nödvändigt att nivåerna av fröspridning och pollen-genflöde är tillräckliga för att säkerhetsställa både kolonisering, etablering och efterföljande populationstillväxt. Nivåer av fröspridning och pollen-genflöde påverkas i sin tur av hur de två könen partitionerar resurser mellan reproduktion, tillväxt och överlevnad. I den första studien har jag kombinerat en fältundersökning, ett frilandsexperiment och en nioårig demografisk studie för att undersöka de demografiska konsekvenserna av könsspecifik resursallokering och för att utreda om könsspecifika skillnader i reproduktiv kostnad kan vara en drivkraft för evolutionen av sexuell dimorfism hos den dioika växten Silene dioica. Jag upptäckte signifikant somatisk intersexuell dimorfism där honor hade betydligt mer ovanjordisk och underjordisk biomassa jämfört med hanar. Över en växtsäsong så investerar honorna mer resurser i reproduktion, vilket i stor utsträckning bekräftar vad som tidigare har observerats i örtartade, dioika växter. Enligt hypotesen för reproduktiv kostnad så bör en hög investering i reproduktion leda till trade-offs med somatiska egenskaper, t.ex. tillväxt. Jag observerade inga somatiska trade-offs och istället fann jag positiva associationer mellan reproduktion och tillväxt hos både honor och hanar. Båda könen verkar ha utvecklat kompensationsmekanismer, även om honorna generellt är mer effektiva i hur de kompenserar för sina reproduktiva kostnader. Vid slutet av en växtsäsong, efter att ha betalat för de nuvarande reproduktiva investeringarna, så är honor bättre än hanar på att allokera resurser till fleråriga strukturer, såsom bladrosetter och rötter. Detta kan potentiellt påverka hur de anlägger sina knoppanlag för nästkommande år och hur väl de överlever vintern. Trade-offs hittades mellan nuvarande reproduktion och framtida reproduktionsmöjligheter och överlevnad men detta var habitat-specifikt och kompensation med hjälp av hur ofta en växt blommar under sin livstid spelar en viktig roll. Hypotesen för reproduktiv kostnad verkar vara en del av förklaringen till den somatiska och demografiska könsdimorfism som observerats i detta system men sexuell selektion, som verkar på hanar, kan vara ett möjligt område för framtida studier. I den andra studien undersökte jag populationsgenetiska konsekvenser av metapopulationsdynamik i Silene dioica. Förekomsten av öar i olika faser av primär succession tillsammans med olika grader av succession inom öar gör det möjligt att undersöka den genetiska dynamiken som uppträder i en åldersstrukturerad metapopulation över flera hierarkiska nivåer. Genetisk mångfald och differentiering uppskattades i åtta unga, nyligen koloniserade populationer och i tio populationer av ett intermediärt successionsstadium. Unga populationer hade lägre genetisk diversitet jämfört med äldre populationer, vilket indikerar att genetiska flaskhalsar, skapade av fåtal antal koloniserande individer, s.k. founders, som härrör från ett begränsat antal källpopulationer, minskar den genetiska diversiteten inom nybildade populationer. Observationen av stark genetisk strukturering, mellan och inom öar, indikerar att genflödet är begränsat över flera rumsliga nivåer i detta system. Bristen på statistiskt signifikanta skillnader i genetisk differentiering mellan unga och intermediära populationer indikerar emellertid att nivåer av genflöde kanske inte är tillräckligt höga för att minska den genetiska differentieringen som uppstår från den ursprungliga founder-händelsen. Mönstren av sexuell dimorfism och hanarnas och honornas roll har utvecklats för att möjliggöra fortlevnad i ett ekologisk och populationsmässigt sammanhang hos Silene dioica. I denna livsmiljö, där öar stiger upp ur havet och skapar nya miljöer för kolonisering samtidigt som autogena primära successionsprocesser leder till utrotning, måste S. dioica kontinuerligt sprida sig mellan olika successionsfaser för att överleva. Den uppenbara framgången för den här dioika växten är uppenbar eftersom den är en av de få dominerande arterna i lövkanten. Detta tyder på att nivåer av fröspridning och genflöde är tillräckliga för att möjliggöra etablering och beständighet av ö-populationer och att de sexuella dimorfismer som har utvecklats i detta metapopulationssystem verkar för att öka nivåerna av genflöde. "Lev hårt – dö ung" -strategin med omfattande blomningar som vi finner hos hanarna kan ha utvecklats som ett sätt att upprätthålla tillräckliga nivåer av genetisk diversitet i metapopulationen men den kommer endast att vara en möjlig strategi om det finns kontinuerliga möjligheter för re-etableringar. Således kan den kontinuerliga landupphöjningen som förekommer i norra delen av Bottniska viken mycket väl vara en förutsättning för den långsiktiga beständigheten av denna dioika, fleråriga växtart. / <p>Felaktigt angivet "Dissertation for PhD" i kolofon.</p>

The canine transmissible venereal tumour (CTVT) is a contagious cancer that is naturally transmitted between dogs by the allogeneic transfer of living cancer cells during coitus. CTVT first arose several thousand years ago and has been reported in dog populations worldwide. The goals of this Thesis were (1) to gain further understanding of CTVT distribution patterns and prevalence around the world, (2) to use genetics to trace the historical spread of CTVT and (3) to map the genetic as well as phenotypic diversity of CTVT tumours around the world. To understand the distribution patterns of CTVT, I obtained information from 645 veterinarians and animal health workers in 109 countries, and generated a snapshot of the locations in which this disease is found. Additionally, as preparation for further genetic analysis, I collected samples from over one thousand CTVT cases from more than 50 countries, optimised methods for high-throughput DNA extraction and quantification and optimised a qPCR-based assay for CTVT diagnosis and host contamination detection. With the goal of tracing the historical spread of CTVT and learning about the genetic diversity of this disease, I sequenced complete mitochondrial genomes of 449 CTVT tumours and their matched hosts. The analysis of the CTVT mitochondrial diversity revealed that CTVT has captured mitochondrial DNA (mtDNA) through horizontal transfer events at least five times during the history of the lineage, delineating five tumour clades. CTVT appears to have spread rapidly around the world within the last 2,000 years, perhaps transported by dogs travelling along historic maritime trade routes. This work indicated that negative selection has operated to prevent accumulation of deleterious mutations in captured mtDNA, and that recombination has caused occasional mtDNA re-assortment. A histology-based screen of CTVT clades did not show any significant phenotypic differences between groups. In order to determine how the five mtDNA clades relate to each other, I analysed data from 539 CTVT exomes. This revealed that a single canine mtDNA haplogroup has recurrently and recently undergone multiple horizontal transfer events. Analysis of this haplotype highlighted a number of candidate genetic variants which may be conferring a selective advantage to this haplotype in CTVT, possibly by influencing mtDNA transcription or replication. Overall, genetic and phenotypic analysis of CTVT tumours from across the globe has broadened our understanding of CTVT diversity, and provided important insights into the biology of a unique transmissible cancer.

No description available.

Submitted by Lara Oliveira (lara@ufersa.edu.br) on 2017-01-04T13:05:22Z No. of bitstreams: 1 CarinaML_TESE.pdf: 1476302 bytes, checksum: d8ce6c34270ba40b6a6e97b30bf6d975 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-01-24T14:44:07Z (GMT) No. of bitstreams: 1 CarinaML_TESE.pdf: 1476302 bytes, checksum: d8ce6c34270ba40b6a6e97b30bf6d975 (MD5) / Made available in DSpace on 2017-03-21T14:51:15Z (GMT). No. of bitstreams: 1 CarinaML_TESE.pdf: 1476302 bytes, checksum: d8ce6c34270ba40b6a6e97b30bf6d975 (MD5) Previous issue date: 2014-03-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The tall coconut palm is about 70% of the coconut farm in Brazil. Nonetheless the information about the genetic variability existing in Brazilian populations and their genetic relationships are still incipient. Microsatellite markers or SSR (Simple Sequence Repeats) and morphological markers are the techniques most suitable for studies of genetic diversity. Thus, knowledge of the variability and genetic structure in the giant coconut palm, it is necessary to direct the activities of conservation and use of germplasm in breeding programs of this species. The objectives of this study were: 1) to analyze the distribution of the genetic variability of the original population of Tall-Brazil-Praia-Forte ( GBrPF - PO), located on the north coast of Bahia, and four coming accesses this population; 2) levels of diversity and genetic relationships between two accesses tall coconut palm collected in Brazil and introduced seven accessions of different geographical regions, conserved in Banco Internacional de Coco for Latin America and the Caribbean (ICG - LAC). The accessions were analyzed using 25 SSR primers specific morphological descriptors and 16 of the list of IPGRI, 1995. Accesses tall- Brazil-Praia-Forte (GBrPF) are conserved in physical bases in Ceará (GBrPF-CE), Pará (GBrPF-PA ) and ICG - LAC, the latter two physical bases in Sergipe: one in the experimental field of the Betume in the city of Neópolis (GBrPF-CEB) and the other in the experimental field Itaporanga in the municipality of Itaporanga d'Ajuda (GBrPF-CEI) . The other accesses greens: tall-do-Brazil-Merepe (GBrMe), collected in the coastal Northeast, tall-Malaysia (GML), tall-Vanuatu (GVT), tall-West African (GOA), tall-Polynesia (GPY), tall-Rennel (GRL), tall-Tonga (GTG) and tall-Rotuma (GRT) introduced in different geographic regions of the world, too are conserved in the ICG - LAC in the experimental field of the Betume. Three studies from this research project will be presented. In the first study, we found 18 polymorphic primers, 91 alelos, with a mean of 5.05 alleles/locus. Genotypic indices indicate greater genetic variability of access GBrPF-PA, GBrPF-CE and GBrPF-CEB, the analysis of gene structure identified an allele sharing and access of the population, suggesting that accesses listed represent the genetic structure of the original population. The grouping (UPGMA) showed the formation of 14 groups, with the GBrPF-CEB and GBrPF-PA showed greater similarity to the original population accesses. In the second study, for the study of genetic relationships among accessions of tall coconut palm, 19 primers were polymorphic, detecting 125 alleles, with an average of 6.57 alleles/locus. Genotypic indices indicate greater genetic variability among accessions of coconut - derived giant introduced the Pacific region. The analysis of gene structure led to the formation of five groups and accessions collected in Brazil showed genetic relationship with the African access and the emergence of ecotypes giant coconut palm in Brazil. Cluster analysis by the Nearest Neighbor method formed two main groups. In group I, the accessions were grouped into three subgroups: Ia (GTG, GRT and GPY), Ib (GRL and GVT) and Ic (GML). In group II, the accessions were separated into two subgroups: IIa (GOA) and IIb (GBrMe, GBrPF),indicating that the genetic relationships of the accessions are based on ecogeographic regions. In the third work, the study of genetic diversity through morphological markers using techniques of univariate and multivariate genetic variability was observed among genotypes. The results of principal component analysis, obtained from 16 morphological characters shows that three components were needed, that the variance explained by them reached a minimum of 80% and the selection of six characters with the highest contribution to the study of diversity. UPGMA was formed by five groups. Group I meets the GVT and GML access; group II with GPY, GTG and GBrPF; group III and IV each with one access, GRT and GOA, respectively, while group V with GBrMe and GRL. Groups showed an inconsistency with respect to the origins of the accessions, probably due to the quantitative nature of those characteristics that are controlled by many genes, being affected by environmental factors. Diversity and genetic structure evaluations demonstrate the variability and genetic relations in giant coconut palm. These results will guide decisions about the activities of conservation and use of coconut germplasm in the country / O coqueiro-gigante representa cerca de 70% da exploração do coqueiro no Brasil. Apesar disso, as informações sobre a variabilidade genética existente nas populações brasileiras e suas relações genéticas ainda são incipientes. Os marcadores microssatélites ou SSR (Simple Sequence Repeats), e os marcadores morfológicos, são as técnicas mais indicadas para os estudos de diversidade genética. Assim, o conhecimento da variabilidade e da estruturação genética em coqueiro-gigante, torna-se necessário para direcionar as atividades de conservação e utilização do germoplasma nos programas de melhoramento da espécie. Os objetivos do presente estudo foram: 1) analisar a distribuição da variabilidade genética da população original de gigante-do-Brasil-da-Praia-do-Forte (GBrPF-PO), localizada do litoral norte do Estado da Bahia, e de quatro acessos procedentes dessa população; 2) os níveis de diversidade e as relações genéticas entre dois acessos de coqueiro-gigante coletados no Brasil e sete acessos introduzidos de diferentes regiões geográficas do mundo, conservados no Banco Internacional de Coco para a América Latina e Caribe (ICG- LAC).Os acessos foram analisados por meio de 25 primers SSR específicos e 16 descritores morfoagronômicos da lista do IPGRI, 1995.Os acessos de gigante-do-Brasil-da-Praia-Forte (GBrPF) são conservados em bases físicas no Ceará (GBrPF-CE), Pará (GBrPF-PA) e no ICG-LAC, este último em duas bases físicas em Sergipe: uma no campo experimental do Betume, no município de Neopólis (GBrPF-CEB) e a outra no campo experimental de Itaporanga, no município de Itaporanga d’Ajuda (GBrPF-CEI). Os demais acessos de coqueiro: gigante-do-Brasil-de-Merepe (GBrMe), coletado no litoral do Nordeste do país, gigante-da-Malásia (GML), gigante-de-Vanuatu (GVT), gigante-do-Oeste-Africano (GOA), gigante-da-Polinésia (GPY), gigante-de-Rennel (GRL), gigante-de-Tonga (GTG) e gigante-de-Rotuma (GRT) introduzidos de diferentes regiões geográficas do mundo, também estão conservados no ICG-LAC no campo experimental do Betume. Três trabalhos oriundos deste projeto de pesquisa serão apresentados. No primeiro trabalho, constatou-se 18 primers polimórficos, 91alelos, com media de 5,05 alelos/loco. Os índices genotípicos indicam maior variabilidade genética dos acessos GBrPF-PA, GBrPF-CE e GBrPF-CEB, a análise da estrutura gênica identificou um compartilhamento de alelos da população e dos acessos, sugerindo que os acessos coletados, representam a estruturação genética da população original. O agrupamento (UPGMA), evidenciou a formação de 14 grupos, tendo os acessos GBrPF-CEB e GBrPF-PA mostrado maior similaridade com a população original. No segundo trabalho, para o estudo das relações genéticas entre acessos de coqueiro-gigante, 19 primers foram polimórficos, detectando 125 alelos, com média de 6,57 alelos/loco. Os índices genotípicos indicam uma maior variabilidade genética entre os acessos de coqueiros-gigantes introduzidos oriundos da região do Pacífico. A análise da estrutura gênica levou a formação de cinco grupos e os acessos coletados no Brasil apresentaram relação genética com o acesso Africano e o surgimento de ecótipos de coqueiro-gigante no Brasil. A análise de agrupamento pelo método do Vizinho mais Próximo formou dois grupos principais. No grupo I, os acessos foram agrupados em três subgrupos: Ia (GTG, GRT e GPY), Ib (GRL e GVT) e Ic (GML). No grupo II, os acessos foram separados em dois subgrupos : IIa (GOA) e IIb (GBrMe, GBrPF). Indicando que as relações genéticas dos acessos são fundamentadas nas regiões ecogeográficas. O terceiro trabalho,o estudo da diversidade genética, por meio de marcadores morfoagronômicos utilizando técnicas de análises uni e multivariadas, foi observada variabilidade genética entre os acessos. Os resultados da análise dos componentes principais, obtidos a partir de 16 caracteres morfoagronômicos mostra que foram necessários três componentes, para que a variância por eles explicada atingisse um mínimo de 80% e a seleção de seis caracteres de maior contribuição para o estudo da diversidade. Pelo método UPGMA formou-se cinco grupos. O grupo I reúne os acessos GVT e GML; o grupo II com o GPY, GTG e GBrPF; o grupo III e IV com apenas um acesso cada, GRT e o GOA, respectivamente e o grupo V com o GBrMe e GRL. Os grupos apresentaram uma incoerência com relação às origens dos acessos, provavelmente devido à natureza quantitativa das características avaliadas, que são controladas por muitos genes, sendo afetadas por fatores ambientais. As avaliações da diversidade e da estruturação genética evidenciam a variabilidade e as relações genéticas existentes em coqueiro-gigante. Esses resultados permitirão orientar as decisões sobre as atividades de conservação e uso do germoplasma do coqueiro no país / 2017-01-04