This study investigates the hybridization of two species of cattails, Typha latifolia (Common Cattail) and T. angustifolia (Narrow-leaved Cattail) in the Czech Republic. The aim of this study was to determine, how often T. latifolia and T. angustifolia hybridize, whether hybridization is allowed by overlapping flowering time of these species and whether it is possible these species controlled cross in a culture. For detection of hybrid individuals were used microsatellite DNA markers, which allow to detect hybridization events and differentiate hybrids from the parental species. Molecular analysis revealed that hybridization of T. latifolia and T. angustifolia occurs in the Czech Republic, but it is not frequent. Of the 267 analyzed individuals, 130 individuals were pure species T. latifolia, 108 individuals pure species T. angustifolia and 29 individuals were hybrids. Of the hybrids, 23 were advanced hybrids, 5 were backcrosses and only one individual was F1 hybrid. Flowering time of T. latifolia and T. angustifolia overlaps, which allows hybridization, and flowering time to not act as a prezygotic reproductive isolation barrier and gametes T. latifolia and T. angustifolia can blend together. In controlled crosses the female spikes T. latifolia and T. angustifolia created seeds, but these were...

O presente trabalho teve por objetivos avaliar o sistema reprodutivo de etnovariedades de batata-doce, mais especificamente, determinar quais genótipos são autocompatíveis e quais são compatíveis ou incompatíveis entre si. O sistema reprodutivo foi avaliado em 13 etnovariedades de batata-doce, através da frutificação e da observação in situ dos tubos polínicos no pistilo através da técnica de epifluorescência com azul de anilina, em flores submetidas a polinização controlada. Teste de viabilidade dos grãos de pólen foi realizado usando os corantes carmim acético e cloreto de tetrazólio em quatro horários diferentes de coleta (6:00; 8:00; 10:00 e 12:00 h). Visando avaliar alguma associação entre a incompatibilidade e a morfologia floral, foram tomadas medidas de todas as peças florais. A frutificação ocorreu apenas nas flores submetidas à polinização cruzada. Do total de 78 cruzamentos realizado, entre as 13 etnovariedades, 46,15% desses é que ocorreu a frutificação. Tubos polínicos nos pistilos foram verificados nas flores autopolinizadas (em 38,46% das etnovariedades) e nas flores submetidas à polinização cruzada (em 85,90% dos cruzamentos). Esses resultados revelam que a batata-doce possui sistema de reprodução sexual mista. A maioria das etnovariedades apresentou taxa de grãos de pólen viáveis acima de 80% quando corados com carmim, mas quando corados com tetrazólio essa taxa foi abaixo de 70%. Entretanto, a variação na viabilidade do pólen nos quatros horários de coleta foi quase inalterada, em ambos corantes. Todas as variáveis florais mensuradas mostraram-se diferenças significativas no nível de 5% de probabilidade, o que revela polimorfismo floral. Quatro padrões bem definido em relação à posição do estigma e da antera mais alta foi estabelecido; estigma bem acima antera, estigma um pouco acima da antera, estigma no mesmo nível da antera e estigma mais abaixo da antera. Mas, neuma associação foi verificada entre a morfologia floral e a incompatibilidade, os cruzamentos ocorreram entre todos os morfotipos. / The objective of this work was to study the reproductive system of sweet potato landraces - specifically, to determine which genotypes are either self-compatible or selfincompatible and which are either compatible or incompatible among themselves. The reproductive system was studied in 13 landraces of sweet potato, by means of the fruit production and in situ observation of the pollen tubes in the pistil with the epifluorescence technique with aniline blue in hand-pollinated flowers. A viability test was performed using the dyes acetic carmine and tetrazolium chloride in fou different collecting times (6:00; 8:00; 10:00 and 12:00 h). In order to detect a possible association between incompatibility and flower morphology, several flower parts were measured. Fruit production occurred only in those flowers subjected to cross-pollination. Among 78 crosses performed between 13 landraces, 46.15% produced fruit. Pollen tubes were observed in the pistils of the self-pollinated flowers of 38.46% of the landraces and of the cross-pollinated flowers of 85.90% of the crosses. These results show that sweet potato has a complex sexual reproductive system. Most landraces had a pollen viability rate over 80% when dyed with carmine, but below 70% when dyed with tetrazolium. However, the variation in pollen viability among the four collecting times was insignificant with either dye. All the flower variables measured showed significant differences at 5% of probability, revealing floral polymorphism. Even within-plant morphological pollen polymorphism, which is rather rare, was found. Four well-defined patterns of the relative position of stigma and highest anther were established: stigma well above the anther; stigma slightly above the anther; stigma at the same level as the anther; and stigma below the anther. However, no association was found between floral morphology and incompatibility patterns. There were successful crosses between all morphotypes.

The selection of crosses is a fundamental part of a breeding program, and the use of an adequate strategy is crucial. A good strategy should balance the selection of the best individuals and maintenance of genetic diversity throughout cycles of breeding, aiming for long-term genetic gains. Among the methods proposed in the literature, we can highlight the genomic prediction with simulated offsprings, which can be used to estimate the mean and genetic variance of each combination of candidate parents, providing useful information to the breeder. However, as far as we know, there are no reports on how this method performs concerning long-term genetic gain. Thus, the goal of this study was to evaluate how genomic prediction with simulated offsprings performs compared with the traditional phenotypic selection across five cycles of breeding. In silico and data-based simulation was used to investigate these approaches in terms of genetic gain and several other parameters related to the genetic diversity. We simulated an In silico standard wheat breeding program, with a capacity to evaluate 1000 lines per cycle. We considered different scenarios for the heritability, number of populations and the number of offspring per population. A real dataset of 1465 wheat inbred lines was also used to perform simulations. In this case, markers were randomly assigned to be genes. The results indicated that the best method is dependent of the heritability of the trait under consideration, the breeder\'s strategy about how many crosses will be done and also if the breeding goal is to have short or long-term genetic gains. In general, the genomic methods, especially the genomic prediction with simulated progenies, presented the best results under scenarios of low heritability and high number of population, either on short or long-term. However, even though the conversion of genetic variability into genetic gains is faster than any other strategy, the losses of variability are also higher, being interesting to bring new sources of variability with the advance of the cycles of breeding. The adoption of the restriction on the number of times a genotype is a parent in crosses is also of fundamental importance for obtaining long-term genetic gains. / A seleção de cruzamentos é parte importante de um programa de melhoramento e o uso de uma estratégia adequada é crucial. Uma boa estratégia deve balancear a seleção dos melhores indivíduos e a manutenção da diversidade genética ao longo dos ciclos de seleção, visando ganhos a longo prazo. Dentre os métodos propostos na literatura podemos destacar a predição genômica com progênies simuladas, que pode ser utilizada para se estimar a média e a variância genética de cada combinação de parentais candidatos, provendo valiosa informação para o melhorista. No entanto, não há relatos sobre como esse método se comporta em um processo de seleção a longo prazo. Portanto, o objetivo desse trabalho foi avaliar a performance do método de predição genômica com progênies simuladas em relação aos métodos tradicionais de seleção fenotípica, ao longo de dez ciclos de melhoramento. Simulações In silico e utilizando um conjunto de dados foram utilizadas para investigar essas metodologias em relação ao ganho genético e diversos outros parâmetros relacionados a diversidade genética. Simulou-se um programa de melhoramento de trigo com capacidade para avaliar 1000 genótipos a cada ciclo. Diferentes cenários para herdabilidade e a combinação número de populações e número de progênies por população foram avaliados. Um conjunto de dados reais de 1465 linhagens de trigo também foi utilizado com o objetivo de proceder com uma simulação baseada em dados reais. Nesse caso, marcas foram aleatoriamente designadas como genes. Os resultados indicam que o melhor método é dependente da herdabilidade da característica, da estratégia adotada pelo melhorista quanto ao número de cruzamentos realizado e também se o objetivo de melhoramento é a obtenção de ganhos genéticos a curto ou à longo prazo. No geral, os métodos envolvendo seleção genômica, especialmente o que faz uso de progênies simuladas, apresentaram melhores resultados quando a herdabilidade é baixa e o número de populações é alta, tanto a curto como à longo prazo. No entanto, embora a conversão de variabilidade genética em ganhos genéticos seja mais rápida com essa estratégia, a perda de variabilidade é mais acentuada, sendo interessante a reposição de novas fontes de diversidade com o avançar dos ciclos de melhoramento. A adoção de uma restrição no número de vezes que um genótipo atua como genitor é, também, de fundamental importância para a obtenção de ganhos à longo prazo.

Epigenetic modification of DNA plays an important role in gene regulation. During gametogenesis and early embryogenesis epigenetic states are reset to ensure embryonic-specific gene expression patterns after fertilization. However, certain genomic regions may resist epigenetic reprogramming. This may result in transgenerational epigenetic inheritance. Earlier, a grandparental origin dependent (GPO) transmission ratio distortion (TRD) of alleles in the distal region of mouse chromosome 12 had been found (Croteau et al ., 2002). The distorted region overlaps with the imprinted region of chromosome 12. The mechanism underlying this TRD is unknown, and we hypothesized that it was due to failure to reset imprints in the imprinted region in a proportion of germ cells. Such an imprint resetting failure would represent a particular case of transgenerational epigenetic inheritance. DNA (Cytosine-5) methyltransferase 1 (DNMT1) plays a key role in the maintenance of epigenetic states in mammalian genomes. To test the role of DNA methylation and DNMT1 in the genesis of TRD and its relationship to epigenetic inheritance we investigated the effect of Dnmt1 loss-of-function mutations using two mouse models: GPO (grandparental origin dependent)-TRD (transmission ratio distortion) and epigenetic inheritance at the agouti locus. Here, we report that Dnmt1 mutations have a modifying parental effect on the transmission of grandparental chromosome 12 alleles. However, the same Dnmt1 mutation did not affect the agouti coat color inheritance patterns in mice that inherited the Avy (agouti viable yellow) mutant allele from the father. Our results suggest that Dnmt1 is a trans-acting modifier of allelic transmission and support the role of epigenetic states in the genesis of TRD.

Made available in DSpace on 2014-06-11T19:32:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-09-28Bitstream added on 2014-06-13T18:43:25Z : No. of bitstreams: 1 muniz_frs_dr_jabo.pdf: 1182648 bytes, checksum: 94ba816afe15c07503cde37414bc5a99 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A variabilidade entre progênies é criada pela segregação cromossômica independente dos genes e pela recombinação genética intracromossomal durante a meiose. O objetivo deste estudo foi analisar a variabilidade derivada de crossing-overs em cruzamentos biparentais (G2 e J2), quádruplos (G4 e J4) e óctuplos (G8 e J8), avaliados em populações segregantes derivadas de parentais contrastantes para resistência ao nematóide de cisto da soja (raça 3) – NCS – e ao oídio - O. A análise foi realizada em populações F2, através de marcadores SSR (single sequence repeat) concentrados em uma região de 55 cM ao redor do gene rmd (resistência ao oídio) e rhg1 (resistência ao NCS). Após o teste dos marcadores, quanto ao polimorfismo, apenas marcadores polimórficos foram utilizados para detectar crossing-over. Todos os marcadores analisados foram não significativos pelo teste de qui-quadrado (P > 0,05), indicando que os valores observados se ajustam à proporção genotípica esperada em F2 (1:2:1). As maiores médias de crossing-over por genótipo foram obtidas para G4 (4,00), no grupo G, e J8 (2,91), no grupo J. Por outro lado, as maiores médias de crossing-over considerando o número de gerações para formar cada população, foram para G2 (2,02) e J8 (0,97). A recombinação entre alelos ocorreu em algumas populações, entretanto para G4 e J8 em 1,89% dos genótipos não ocorreram. Em geral, nos cruzamentos com maior número de parentais envolvidos a ocorrência de crossingover foi maior, sendo satisfatórios na criação de variabilidade. O progresso no melhoramento de soja tem sido alcançado em partes pela criação de novas combinações alélicas dentro dos cromossomos. / The variability among the progenies is created by chromosome segregation, independent assortment of genes, and intra-chromosomal genetic recombination during meiosis. The objective of this study was to analyze the variability derived from crossovers in soybean biparental (G2 and J2), quadruple (G4 and J4) and octuple (G8 and J8) crosses, measured in segregant population derived from contrasting parental regarding their resistance to cist nematode (race 3) – SCN and powdery mildew – PM. The analyses were made in F2 population through SSR (single sequence repeat) markers located in a 55CM region around Rmd (powdery mildew) and Rhg1 (cist nematode) resistance genes. After screening makers for their polymorphism, only polymorphic markers were used to detect crossovers. All markers were not significant by chi-square test (P > 0.05), showing that observed values corroborates to genotypic inheritance ratio expected in F2 population (1:2:1). Thus, the higher average of crossovers for some populations were observed for G4 (4.00), at linkage group G and J8 (2.91), at linkage group J. On the other hand, the higher average of crossovers considering the generation number to form each population, was found for G2 (2.02) and J8 (0.97). The recombination between alleles occurred in some populations, however, to G4 and J8, in 1.89% of the genotypes not showing crossover. In general, the crosses with larger numbers of parents showed higher number of crossovers, being very satisfactory for the creation of genetic variability. Soybean breeding progress has been accomplished in part by creating on new within_chromossome allele combinations.

Submitted by Alisson Mota (alisson.davidbeckam@gmail.com) on 2015-06-30T19:17:25Z No. of bitstreams: 1 Dissertação - Pablo Roberto da Silva Ozório.pdf: 773168 bytes, checksum: 226550639f3d6045ccb166d38e42a2c4 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-07-06T17:36:33Z (GMT) No. of bitstreams: 1 Dissertação - Pablo Roberto da Silva Ozório.pdf: 773168 bytes, checksum: 226550639f3d6045ccb166d38e42a2c4 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-07-06T17:42:05Z (GMT) No. of bitstreams: 1 Dissertação - Pablo Roberto da Silva Ozório.pdf: 773168 bytes, checksum: 226550639f3d6045ccb166d38e42a2c4 (MD5) / Made available in DSpace on 2015-07-06T17:42:05Z (GMT). No. of bitstreams: 1 Dissertação - Pablo Roberto da Silva Ozório.pdf: 773168 bytes, checksum: 226550639f3d6045ccb166d38e42a2c4 (MD5) Previous issue date: 2013-06-26 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The genetic diversity among 18 guarana cultivars was characterized using 20 morphological descriptors including production aiming to support the selection of genetically divergent parents for controlled crosses. The similarity between cultivars was calculated using Gower general similarity coefficient. The dendrogram was constructed based on similarity matrix using the UPGMA clustering criterion. The scatter diagram of the cultivars was constructed based on the method of Principal Coordinates Analysis (PCO). Data were analyzed using the computational resources of the GENES program and MVSP v.3.22. Pairs of similar genotypes were BRS CG505 and BRS CG612 (0,823); BRS Amazonas and BRS CG608 (0,820); BRS Mundurucânia and BRS CG189 (0,807); BRS Cereçaporanga and BRS Andirá (0,805); BRS Marabitana and BRS Maués (0,796); BRS CG189 and BRS CG611 (0,784); BRS Andirá and BRS CG850 (0,771); BRS CG610 and BRS CG505 (0,770); BRS Saterê and BRS CG372 (0,717); BRS CG648 and BRS Andirá (0,703). Genotype pairs were less similar: BRS and BRS Marabitana CG850 (0.699); BRS BRS CG611 and CG882 (0.688); CG505 BRS and BRS Saterê (0.663); BRS BRS CG850 and CG612 (0.646); CG189 BRS and BRS Luzéia (0.640); Saterê BRS and BRS Andirá (0.628); BRS BRS CG189 and CG850 (0.585); BRS 372 and BRS CG850 CG (0.573). The dendrogram formed by the UPGMA method, obtained from the genetic distance Gower using a cutoff value of 0.64 allowed the formation of four groups, and indicated that there is high genetic diversity among cultivars currently recommended for planting in the State Amazon Embrapa Western Amazon. The graphic dispersion analysis method PCO showed good agreement with the cluster analysis by UPGMA method and showed great genetic variability among cultivars evaluated guarana in this work. / A divergência genética entre 18 cultivares de guaraná foi caracterizada utilizando 20 descritores morfoagronômicos inclusive produção visando subsidiar a seleção de genitores geneticamente mais divergentes para cruzamentos controlados. A similaridade entre as cultivares foi calculada utilizando o coeficiente de similaridade geral de Gower. O dendrograma foi calculado com base na matriz de semelhança, utilizando o método UPGMA como critério de agrupamento. O diagrama de dispersão das cultivares foi construído com base no método de Análise das Coordenadas Principais (PCO). Os dados foram analisados utilizando-se os recursos computacionais do programa GENES e do programa MVSP v.3.22. Os pares de genótipos mais similares foram: BRS CG505 e BRS CG612 (0,823); BRS Amazonas e BRS CG608 (0,820); BRS Mundurucânia e BRS CG189 (0,807); BRS Cereçaporanga e BRS Andirá (0,805); BRS Marabitana e BRS Maués (0,796); BRS CG189 e BRS CG611 (0,784); BRS Andirá e BRS CG850 (0,771); BRS CG610 e BRS CG505 (0,770); BRS Saterê e BRS CG372 (0,717); BRS CG648 e BRS Andirá (0,703). Os pares de genótipos menos similares foram: BRS Marabitana e BRS CG850 (0,699); BRS CG611 e BRS CG882 (0,688); BRS CG505 e BRS Saterê (0,663); BRS CG850 e BRS CG612 (0,646); BRS CG189 e BRS Luzéia (0,640); BRS Saterê e BRS Andirá (0,628); BRS CG189 e BRS CG850 (0,585); BRS CG 372 e BRS CG850 (0,573). O dendrograma formado pelo método hierárquico UPGMA, obtido a partir da distância genética de Gower utilizando como ponto de corte o valor de 0,64 permitiu a formação de quatro grupos, e indicou que existe alta divergência genética entre as cultivares atualmente recomendadas para plantio no Estado do Amazonas pela Embrapa Amazônia Ocidental. A análise de dispersão gráfica pelo método PCO apresentou boa concordância com a análise de agrupamento pelo método hierárquico UPGMA e evidenciou grande variabilidade genética entre as cultivares de guaraná avaliadas no trabalho.

O presente trabalho teve por objetivos avaliar o sistema reprodutivo de etnovariedades de batata-doce, mais especificamente, determinar quais genótipos são autocompatíveis e quais são compatíveis ou incompatíveis entre si. O sistema reprodutivo foi avaliado em 13 etnovariedades de batata-doce, através da frutificação e da observação in situ dos tubos polínicos no pistilo através da técnica de epifluorescência com azul de anilina, em flores submetidas a polinização controlada. Teste de viabilidade dos grãos de pólen foi realizado usando os corantes carmim acético e cloreto de tetrazólio em quatro horários diferentes de coleta (6:00; 8:00; 10:00 e 12:00 h). Visando avaliar alguma associação entre a incompatibilidade e a morfologia floral, foram tomadas medidas de todas as peças florais. A frutificação ocorreu apenas nas flores submetidas à polinização cruzada. Do total de 78 cruzamentos realizado, entre as 13 etnovariedades, 46,15% desses é que ocorreu a frutificação. Tubos polínicos nos pistilos foram verificados nas flores autopolinizadas (em 38,46% das etnovariedades) e nas flores submetidas à polinização cruzada (em 85,90% dos cruzamentos). Esses resultados revelam que a batata-doce possui sistema de reprodução sexual mista. A maioria das etnovariedades apresentou taxa de grãos de pólen viáveis acima de 80% quando corados com carmim, mas quando corados com tetrazólio essa taxa foi abaixo de 70%. Entretanto, a variação na viabilidade do pólen nos quatros horários de coleta foi quase inalterada, em ambos corantes. Todas as variáveis florais mensuradas mostraram-se diferenças significativas no nível de 5% de probabilidade, o que revela polimorfismo floral. Quatro padrões bem definido em relação à posição do estigma e da antera mais alta foi estabelecido; estigma bem acima antera, estigma um pouco acima da antera, estigma no mesmo nível da antera e estigma mais abaixo da antera. Mas, neuma associação foi verificada entre a morfologia floral e a incompatibilidade, os cruzamentos ocorreram entre todos os morfotipos. / The objective of this work was to study the reproductive system of sweet potato landraces - specifically, to determine which genotypes are either self-compatible or selfincompatible and which are either compatible or incompatible among themselves. The reproductive system was studied in 13 landraces of sweet potato, by means of the fruit production and in situ observation of the pollen tubes in the pistil with the epifluorescence technique with aniline blue in hand-pollinated flowers. A viability test was performed using the dyes acetic carmine and tetrazolium chloride in fou different collecting times (6:00; 8:00; 10:00 and 12:00 h). In order to detect a possible association between incompatibility and flower morphology, several flower parts were measured. Fruit production occurred only in those flowers subjected to cross-pollination. Among 78 crosses performed between 13 landraces, 46.15% produced fruit. Pollen tubes were observed in the pistils of the self-pollinated flowers of 38.46% of the landraces and of the cross-pollinated flowers of 85.90% of the crosses. These results show that sweet potato has a complex sexual reproductive system. Most landraces had a pollen viability rate over 80% when dyed with carmine, but below 70% when dyed with tetrazolium. However, the variation in pollen viability among the four collecting times was insignificant with either dye. All the flower variables measured showed significant differences at 5% of probability, revealing floral polymorphism. Even within-plant morphological pollen polymorphism, which is rather rare, was found. Four well-defined patterns of the relative position of stigma and highest anther were established: stigma well above the anther; stigma slightly above the anther; stigma at the same level as the anther; and stigma below the anther. However, no association was found between floral morphology and incompatibility patterns. There were successful crosses between all morphotypes.

La spéciation peut être définie comme l’ensemble des processus conduisant à l’évolution de l’isolement reproducteur entre groupes d’individus. Ces dernières décennies, de nombreuses études ont souligné l’importance de la sélection naturelle comme processus majeur dans la formation de nouvelles espèces en conditions de sympatrie, notamment dans des modèles de spéciation écologique. Le chêne sessile (Quercus petraea (Matt.) Liebl.) et le chêne pédonculé (Q. robur L.) sont deux espèces sympatriques qui présentent de fortes divergences morphologiques et écologiques, malgré des taux d’hybridation naturelle estimés relativement importants. Cependant, très peu de données sont connues sur la nature et la force des barrières reproductives chez ces espèces. L’objectif de cette thèse était donc de caractériser ces barrières aux niveaux phénotypique et génétique, pour mieux comprendre leur importance relative, leur rôle dans le processus de divergence et leur évolution au sein de ce complexe d’espèces. Une première approche basée sur la réalisation de croisements contrôlés a montré tout d’abord (i) l’existence de fortes barrières reproductives au niveau pré-zygotique et de barrières significatives bien que plus faibles au niveau de la fitness des descendants hybrides, et (ii) une variabilité importante de ces barrières liée aux génotypes des individus et à leur expression dans des micro-environnements différents. Une deuxième approche de génomique des populations sur 33 gènes candidats à l’isolement reproducteur pré-zygotique a ensuite permis d’identifier des « gènes de spéciation » soumis à de la sélection divergente, liés en particulier à la phénologie de la floraison, et d’apporter des éléments de discussion supplémentaires au modèle de colonisation de ces espèces en peuplements naturels. / Speciation can be defined as the range of processes that lead to the evolution of reproductive isolation among groups of individuals. Past decades have witnessed a renewal in the recognition of natural selection as a primary force in the formation of new species, in particular for ecological speciation models in conditions of sympatry. Sessile oak (Quercus petraea (Matt.) Liebl.) and pedunculate oak (Q. robur L.) are two sympatric species which exhibit large morphological and ecological differences, despite relatively high estimated rates of natural hybridization. However, very little is known about the nature and strength of reproductive barriers between those two species. The objective of this thesis was therefore to characterize their isolating barriers at phenotypic and genetic levels, in order to better understand their relative importance, their role in the process of divergence and their evolution in that species complex. A first approach based on controlled crosses has shown (i) the existence of strong barriers at the pre-zygotic level and that of significant although weaker ones at the post-zygotic level, based on observations from fitness of hybrid progenies, and (ii) a large variability for traits linked to barriers phenotypes, across genotypes and also for their expression in different micro-environments. A second approach of population genomics used 33 candidate genes to reproductive isolation and allowed to identify «speciation genes» submitted to divergent selection, the strongest divergence being observed for genes involved in the flowering pathway. The model of colonization of these oak species in natural stands was discussed in the light of these new results.

No description available.

Thesis (MCurr)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The global epidemic of HIV continues with an estimated 2.2 million children under 15 years of age worldwide living with HIV and 640 000 newly infected in 2004 (WHO, 2009). HIV crosses the blood–brain barrier which may lead to neuronal damage and death. There is controversial evidence within available research on effects of HIV on cognitive and motor development in children because of the limitations imposed by study designs, study populations and study methodological quality. The aims of the review were: - To conduct a systematic review of published research to establish the effects and the prevalence of HIV infection on cognitive and motor development in children. - To critically appraise the methodological quality of published research regarding cognitive and motor development of HIV infected children. The objectives of the review were: - To assess evidence on the cognitive and motor development of HIV-1 infected children - To describe anthropometric outcomes including: weight for age, weight for height, height for age and head circumference in children with a HIV infection. - To assess the methodological quality of studies on the cognitive and motor development of HIV infected children. The following databases were searched for identification of articles; MEDLINE, Google Scholar, AIDSTRIALS, AIDSLINE and CINHAL. The search time frame included published works from inception to July 2011 without language restrictions. Analytical observational trials that assessed at least one outcome (cognitive or motor development or 1 of the anthropometric outcomes) between HIV positive and HIV negative children aged 5 years and below or children with a mean age of less than 5 years were employed. Two review authors independently searched for eligible studies, evaluated methodological quality and extracted the data. Meta-analysis was carried out using Rev Man 5.1 using the risk ratio for categorical data and standard mean difference for continuous data. Fifteen studies with a total of 3 086 participants met the inclusion criteria. HIV infected children were 2.45 times at higher risk of developing cognitive developmental delay than HIV negative children (RR, 95% CI, 1.95, 3.07, P < 0.00001). Infected children scored - 0.54 less than HIV negative children (SMD 95% CI, -0.70, -0.39, 97, p < 0.00001) for cognitive development and -0.68 in motor development (SMD 95% CI, -0.82, -0.55, p< 0.00001). The risk of motor developmental delays was 2.95 times in HIV positive compared with HIV negative children (RR 95% CI, 2.19, 3.99, p < 0.00001). HIV infected children are slower in aspects of cognitive and motor development compared to their HIV negative counterparts. They also showed delays in anthropometric outcomes; weight for age and height for age. Study design influenced results of the studies with children scoring more on cross sectional than cohort studies. There is still need to develop culturally appropriate or standardise neurodevelopment tools as most African studies still rely on international tools. More evidence is needed on the effectiveness of HAART in reducing cognitive and motor delay. / AFRIKAANSE OPSOMMING: Die wêreldwye MIV epidemie duur voort met ongeveer 2.2 miljoen kinders onder 15 jarige ouderdom wat wêreldwyd met MIV leef en 640 000 onlangs in 2004 geïnfekteerd (WHO, 2009). MIV strek oor die bloed-brein grens wat kan lei tot neuronale skade en die dood. Daar is kontroversiële bewys binne beskikbare navorsing oor die effek wat MIV het op kognitiewe en motoriese ontwikkeling in kinders, vanweë die beperkinge wat geplaas word deur studie ontwerpe, studie bevolkings en studie metodologiese kwaliteit. Die doelwitte van die oorsig is om - ‘n sistematiese oorsig van gepubliseerde navorsing te doen om sodoende die effek en voorkoms van MIV infeksie op kognitiewe en motoriese ontwikkeling by kinders vas te stel - ’n kritiese waardering van die metodologiese kwaliteit van gepubliseerde navorsing te doen ten opsigte van die kognitiewe en motoriese ontwikkeling van MIV geïnfekteerde kinders. Die doelwitte van die oorsig is om - assessering te doen van die bewyse van kognitiewe en motoriese ontwikkeling by MIV-1 geïnfekteerde kinders - antropometriese uitkomste te beskryf, insluitend: gewig vir ouderdom, gewig vir hoogte, hoogte vir ouderdom en omtrek van die hoof by kinders met ’n MIV infeksie - die metodologiese kwaliteit te assesseer van studies op die kognitiewe en motoriese ontwikkeling van MIV geïnfekteerde kinders. Die volgende databasisse is nagevors vir die identifisering van artikels: MEDLINE, Google Scholar, AIDSTRIALS, AIDSLINE en CINHAL. Die tydraamwerk vir navorsing het gepubliseerde werk ingesluit vanaf aanvang tot Julie 2011 sonder taalbeperkings. Analitiese waarneembare toetse wat ten minste een uitkoms geassesseer het (kognitiewe of motoriese ontwikkeling of 1 van die antropometriese uitkomste) tussen MIV positiewe en MIV negatiewe kinders van 5 jarige ouderdom en jonger, of kinders met ’n gemiddelde ouderdom van minder as 5 jaar is betrek. Twee oorsig outeurs het onafhanklik vir geskikte studies gesoek, metodologies geëvalueer en data getrek. Meta-analise was uitgevoer deur gebruik te maak van Rev Man 5.1 met behulp van die risiko-ratio vir kategoriese data en die standaard gemiddelde verskil vir aaneenlopende data. Vyftien studies met ’n totaal van 3 086 deelnemers met die insluitingskriteria. MIV geïnfekteerde kinders het 2.45 keer ’n hoër risiko gehad om kognitiewe ontwikkelingsvertraging te ontwikkel as MIV negatiewe kinders (RR, 95% CI, 1.95, 3.07, P< 0.0000). Geïnfekteerde kinders het ’n -0.54 telling behaal, minder as MIV negatiewe kinders (SMD 95% CI, -0.70, -0.39,97 p < 0.00001) vir kognitiewe ontwikkeling en -0.68 vir motoriese ontwikkeling (SMD 95% CI, -0.82, -0.55, p< 0.00001). Die risiko van motoriese ontwikkelingsvertragings was 2.95 keer by MIV positiewe in vergelyking met MIV negatiewe kinders (RR 95% CI, 2.19, 3.99. p < 0.00001). MIV geïnfekteerde kinders is stadiger in aspekte van kognitiewe en motoriese ontwikkeling in vergeyking met hulle MIV negatiewe eweknieë. Hulle het ook vertragings getoon in antropometriese uitkomste; gewig vir ouderdom en hoogte vir ouderdom. Studie ontwerpe het uitslae beïnvloed van die kinders wat ’n hoër telling behaal het met deursnee as in kohort studies. Daar is nog ’n behoefte om kultureel geskikte of gestandaardiseerde neuro-ontwikkelingsinstrumente te ontwikkel, omdat die meeste Afrika-studies nog steeds staat maak op internasionale instrumente. Meer bewyse is nodig aangaande die effektiwiteit van HAART om kognitiewe en motoriese vertraging te verminder.