A caracterização fenotípica representa uma temática clássica na biologia evolutiva e o modo como diferentes caracteres respondem aos processos evolutivos tem sido problemática frequente em estudos envolvendo as mais diversas espécies. O presente trabalho visou investigar justamente como determinado fenótipo se comporta mediante o fluxo gênico. Primeiramente, explorou-se a possibilidade de se identificar e distinguir a partir de análises de traços craniométricos indivíduos anteriormente separados quanto a cor em três grupos: brancos, negros e pardos. Em um segundo momento, testou-se se a morfologia craniana expressa por indivíduos classificados como pardos seria intermediária em comparação com a expressa por brancos e negros. As análises estatísticas uni e multivariadas empregadas sobre os diferentes bancos de dados (dados brutos, dados das parcelas masculina e feminina separadamente, dados corrigidos para tamanho e também corrigidos para normalidade) apontaram ser possível discriminar os indivíduos previamente classificados de acordo com a cor em brancos, negros e pardos. Estes últimos, por sua vez, apresentam morfologia intermediária entre os grupos considerados parentais. Tais resultados permitem inferir que traços craniométricos, além de bons marcadores para a compreensão das relações histórico-biológicas populacionais, também seguiram o esperado como resposta ao fluxo gênico para um modelo de genética aditiva clássica segundo o qual a população híbrida apresenta frequências médias entre as populações parentais. Apesar de cor da pele e morfologia craniana representarem fenótipos com diferentes histórias evolutivas, observou-se correlação entre os dois caracteres para esta amostra, evidenciando-se que ambos representaram bons marcadores de mistura entre populações / Phenotypic characterization is a classic theme in evolutionary biology. The way different characters respond to evolutionary processes has been a frequent issue in studies involving a diverse number of species. This study aimed to investigate how a particular phenotype behaves by gene flow. First, it was explored the possibility to use analysis of craniometric traits to identify and distinguish individuals previously sorted by color into three groups: white, black and brown. Secondly, it was tested whether the cranial morphology expressed by individuals classified as brown would be intermediate compared to that expressed by whites and blacks. The univariate and multivariate statistical analysis used for the different databases (raw databases, data from male and female portions separately, data ajusted regarding size factor and normality) pointed out to be possible to discriminate individuals previously classified as white, black and brown, the latter being presented as an intermediate morphology between the considered parental groups. These results indicate that craniometric traits, besides being good markers for understanding the historical-biological population relationships, also followed as expected in response to gene flow for a classic additive genetic model, in which the hybrid population has medium frequencies between parental populations. Although skin color and cranial morphology represent phenotypes with different evolutionary histories, it was observed a correlation between the two characters for this sample, indicating that both represent good markers for mixture between populations

A erva-mate, Ilex paraguariensis, é uma espécie dioica, clímax com ampla área de distribuição natural. A despeito de sua importância econômica e ecológica são escassos os estudos de conservação e genética da espécie. O objetivo geral do trabalho foi estudar a diversidade genética, a estrutura genética espacial e o fluxo gênico por dispersão de sementes em duas populações naturais de I. paraguariensis na área do entorno do Parque Nacional do Iguaçu, com uso de marcadores moleculares microssatélites. Foram encontrados baixos níveis de diversidade genética em oito loci analisados, com divergência genética maior entre do que dentro das populações. A I. paraguariensis apresentou baixa densidade populacional, com 0,27 a 0,29 árvores por ha-1 e distribuição espacial agregada, entretanto não foi observado evidência de estrutura genética espacial. A média da distância da dispersão de pólen foi de 393 m e a dispersão de sementes atingiu distância próximas a 2.000 m. Os resultados obtidos, sugerem que a base genética da espécie não é ampla, o que pode dispor a I. paraguariensis a um estado crítico de conservação, devido a de erosão genética provocada pela destruição de seus ambientes naturais. / The yerba mate, Ilex paraguariensis, is a species dioecious, climax with wide natural range. Despite their economic and ecological importance are few studies of genetics and conservation of the specie. The overall objective this work was to study the genetic diversity, spatial genetic structure and gene flow by seed dispersal in two natural populations of I. paraguariensis around the National Park of Iguassu, using microsatellite molecular markers. It found low levels of genetic diversity at eight loci analyzed, and greater genetic divergence between populations than within population. The I. paraguariensis showed low population density with 0.27 to 0.29 trees per ha-1 and spatial clustered distribution, however was not observed evidence of spatial genetic structure. The average distance of pollen dispersal was 393 m and seed dispersal reached near 2,000 m. The results suggest that the genetic basis of species is not large, which may carry the I. paraguariensis to critical state of conservation due to genetic erosion caused by the destruction of their natural environments.

Rapid range expansion of newly invasive species provides a unique opportunity for studying patterns of dispersal and gene flow. In this thesis, I examined the effect of landscape features on gene flow in the invasive grass Brachypodium sylvaticum at the edge of its expanding range. I used genome-wide Single Nucleotide Polymorphism (SNP) surveys of individuals from 22 locations in the Clackamas Watershed in the Portland, Oregon metropolitan region to assess genetic diversity and structure, to identify putative source populations, and to conduct landscape genetic analyses. Resistance surfaces were created for each landscape feature, using ResistanceGA to optimize resistance parameters. My STRUCTURE analysis identified three distinct clusters, and diversity analyses support the existence of at least two local introductions. Multiple Regression on distance Matrices (MRM) showed no evidence that development, roads, canopy cover, or agriculture had a significant influence on genetic distance in B. sylvaticum. The effect of geographic distance was marginal and reflected geographic clustering. The model of rivers acting as a conduit explained a large portion of variation in genetic distance. Results indicate that rivers influence patterns of dispersal of B. sylvaticum by human recreational activity centering on use of rivers, and possibly due to movement of deer.

Acacia saligna is a native species complex with a widespread natural distribution throughout the south west of Western Australia. It is being developed as an agroforestry crop to produce low value, bulk biomass products in the low rainfall agricultural areas of southern Australia. This thesis develops knowledge to assist the domestication and breeding program of A. saligna as an agroforestry cultivar. It also furthers development of a risk management plan for utilisation of the Acacia saligna species complex. Highly informative microsatellite markers for A. saligna were developed for use in mating system studies, paternity analysis and in the development of a diagnostic tool for the identification of individuals and populations at the subspecific level. Microsatellites developed in other Acacia species were also screened for utility in A. saligna. A high level of outcrossing (mean multilocus outcrossing rate of 0.98) and little true selfing was found for a planted stand of A. saligna subspecies saligna. Paternity analysis indicated heterogeneity in pollen clouds experienced by maternal trees and an essentially random pattern of mating within the stand. Inter-subspecific pollen immigration into the stand from trees of subspecies lindleyi was detected for 14% of progeny analysed and occurred over distances greater than 1500 m. Extensive intra-subspecific pollen-mediated gene flow is maintained between remnant natural populations of A. saligna subspecies lindleyi, and a high level of inter-subspecific pollen immigration from trees in the planted stand of A. saligna subspecies saligna was detected in remnant populations of subspecies lindleyi (32% of analysed progeny) occurring over distances greater than 1500 m. Polymorphic microsatellite markers used to investigate genetic structuring within A. saligna revealed a high level of genetic divergence between subspecific entities congruent with a taxonomic reclassification of the species complex. Selected microsatellite markers also proved suitable for use as a rapid diagnostic tool that can be used to characterise populations into one of the proposed subspecies of A. saligna with high probability. These results indicate that high levels of outcrossing and essentially random patterns of mating that maintain genetic diversity in seed crops should be achievable with the suitable management of seed production stands of A. saligna. Appropriate management techniques that limit genetic contamination into seed production stands will need to be employed to achieve this goal. Management techniques will also be required to minimise the risk of genetic contamination from stands planted for agroforestry purposes into remnant natural populations. Isolation distances greater than 1500 m between genetically divergent agroforestry crops and natural populations are suggested in both cases and key areas of further research are suggested. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1336865 / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2008

<p>The identification of processes governing genetic structure at different spatial scales remains a major challenge in evolutionary biology and is of considerable applied interest in conservation biology. In <i>Euphrasia stricta</i> five varieties have been identified (<i>brevipila</i>, <i>gotlandica</i>, <i>stricta</i>, <i>suecica</i> and <i>tenuis</i>) based on differences in habitat, phenology and morphology. In this thesis, I examined genetic variation at AFLP and microsatellite marker loci in relation to variation in habitat and morphology within and among varieties of <i>E. stricta</i> on the island Gotland in the Baltic Sea. The results are discussed in relation to evolutionary processes acting within this species complex. </p><p>In a study conducted at the regional scale, the two early-flowering varieties <i>suecica</i> and <i>tenuis</i> each formed a genetically distinct group, while the three late-flowering varieties <i>brevipila</i>, <i>gotlandica</i> and <i>stricta</i> formed a third group. The results suggest that <i>suecica</i> and <i>tenuis</i> have ancient origins since they are genetically different both from the <i>brevipila</i>/<i>gotlandica</i>/<i>stricta</i> group and from each other despite their similar habitat preferences. This pattern was obtained using both marker systems. Discrepancies between AFLP and microsatellites were found in patterns of isolation by distance and in estimates of expected heterozygosity, <i>H</i>_e.</p><p>Focusing on the mixed genetic group <i>brevipila</i>/<i>gotlandica</i>/<i>stricta</i> and the causes behind their clustering together despite differences in morphology and habitat preferences, I performed a study at a smaller geographic scale. Studying a population of <i>E. stricta</i> I found that, although gene flow within the population was strong, it had not prevented the formation of genetic groups associated with micro-habitat properties. </p><p>An important result for conservation of the rare variety <i>suecica</i> is its distinct genetic separation from variety <i>tenuis</i>. If the aim of conservation is to preserve the uniqueness of <i>suecica,</i> the two varieties should be treated as separated entities. </p>

The identification of processes governing genetic structure at different spatial scales remains a major challenge in evolutionary biology and is of considerable applied interest in conservation biology. In Euphrasia stricta five varieties have been identified (brevipila, gotlandica, stricta, suecica and tenuis) based on differences in habitat, phenology and morphology. In this thesis, I examined genetic variation at AFLP and microsatellite marker loci in relation to variation in habitat and morphology within and among varieties of E. stricta on the island Gotland in the Baltic Sea. The results are discussed in relation to evolutionary processes acting within this species complex. In a study conducted at the regional scale, the two early-flowering varieties suecica and tenuis each formed a genetically distinct group, while the three late-flowering varieties brevipila, gotlandica and stricta formed a third group. The results suggest that suecica and tenuis have ancient origins since they are genetically different both from the brevipila/gotlandica/stricta group and from each other despite their similar habitat preferences. This pattern was obtained using both marker systems. Discrepancies between AFLP and microsatellites were found in patterns of isolation by distance and in estimates of expected heterozygosity, He. Focusing on the mixed genetic group brevipila/gotlandica/stricta and the causes behind their clustering together despite differences in morphology and habitat preferences, I performed a study at a smaller geographic scale. Studying a population of E. stricta I found that, although gene flow within the population was strong, it had not prevented the formation of genetic groups associated with micro-habitat properties. An important result for conservation of the rare variety suecica is its distinct genetic separation from variety tenuis. If the aim of conservation is to preserve the uniqueness of suecica, the two varieties should be treated as separated entities.

<p><p>Understanding the ecological and evolutionary responses of plant species to shifts in climate (and other rapid environmental perturbations) will require an improved knowledge of interactions between ecological and evolutionary processes as mediated by reproduction and gene flow. This dissertation research examines the processes of seed dispersal, intra- and inter-specific gene flow, and reproductive success in two red oak populations in North Carolina; the variation in these processes from site to site; and their influence on genetic structure, population dynamics, and migration potential.</p> <p><p>Using genetic and ecological data collected from two large long-term study sites, I develop a hierarchical Bayesian model to identify the parents of sampled seedlings and characterize the scale of effective seed and pollen dispersal. I examine differences in scale of dispersal between the Appalachian and Piedmont sites in light of the spatial genetic structure and ecological differences of the two sites. I then use the pedigree and dispersal estimates derived from these analyses to examine variation in reproductive success and to test hypotheses about the causes and consequences of such variation. Using parentage estimates and measures of genetic differentiation between species, I study the likely extent of hybridization in these mixed-species secondary forests. Finally, using the SLIP stand simulator, I explore the implications of new genetic dispersal estimates for migration potential in oaks.</p> <p><p>I find that effective seed dispersal distances are longer than estimated using seed trap data. While at the Piedmont site the large number of seedling found >100 m from their mother trees suggests that animal dispersers play a vital role, at the Appalachian site seedling distributions conform more closely to the original gravity-created pattern of seed density. Individual trees vary widely in their reproductive success. Seedling production was found to be positively associated with annual seed production, but exhibited hump-shaped or reversing relationships with age (suggesting the effect of senescence) and growth rate (suggesting tradeoffs in allocation). Germination fraction was negatively associated with fecundity, suggesting that density-dependent mortality may be acting on the high concentrations of seeds near highly fecund adults. Due to overlapping generations and variation in individual reproductive success, effective population size is estimated to be less than half the size that numbers of "adult" individuals would suggest, with consequences for the relative strength of drift and selection. Hybridization may boost effective population size somewhat; my analyses suggest that inter-specific gene flow is common at both study sites. Finally, simulations show that dispersal has a relatively stronger effect on migration rate and population growth than fecundity or size at maturity, and that genetic estimates of seed dispersal can yield significantly higher rates of migration and/or population persistence than seed-trap based estimates under both competitive and non-competitive conditions.</p> / Dissertation

Abstract Sequence variation of the atpB-rbcL noncoding spacer region of the chloroplast DNA was used to reconstruct the phylogeography of Tetraena mongolica.T. mongolica (Zogophylaceae) is a relict species of a monotypic genus of in Inner Mongolia of China. It has been listed as seriously endangered plants that only distributed on the Ordos plateau of Inner Mongolic. The area is a refuge of many relict Asian Plants. Reproduction of T. mongolica is mainly by seed but a reproduction is anther way under the stress. A total of 880 bp of the atpB-rbcL spacer of cpDNA was sequenced from 8 populations of T. Mongolic. According to the cpDNA data, the level of gene flow (Nm:0.04-2.01), and population differentiation (Fst:0.199-0.895) were indicated, and the ¡§isolation by distance¡¨ model was not supported (R2 =0.0024). Based on minimum spanning network and nested clade analysis, the past fragmentation is the main phylogeographic factor affecting the population structure of T. mongolica .We suggested the deluges of Yellow River and isolation of Gianlishan Mountain cased the population fragmentation of T. mongolica. Keywords: phylogeography, Tetraena mongolica, gene flow, population differentiation, nested clade analysis, past fragmentation

The Canary Island pine, Pinus canariensis, is an endemic tree that forms one of the main forest ecosystems within the archipelago, and whose distribution has been reduced in the last five centuries by clear cutting for the extraction of timber and tar. It was in the XXth century that exploitation declined and reforestation programs were brought forward for the restoration of an ecosystem that harbours a number of endangered endemic species of plants and animals. In addition to reforestation efforts, an understanding of population genetic processes is also necessary for the successful conservation management of the Canarian pine forest, particularly in light of gathering evidence for local adaptation.<br /><br />In this thesis historical and contemporary gene flow within P. canariensis was studied with nuclear and chloroplast microsatellite markers. High immigration rates (0.68–0.75) were estimated as expected for an outcrossing windpollinated tree. Nevertheless, significant population differentiation (theta = 0.019, RST = 0.044) was detectable for sites separated by only a few kilometres. Within the context of reforestation programs the high levels of gene flow detected would appear to have a positive effect on reforested stands by facilitating the immigration of local alleles from natural stands into potentially genetically depauperate first generation gene pools of reforested stands.<br /><br />Historical population growth was revealed with chloroplast microsatellites for most populations of P. canariensis. Population expansions for the pine parasite weevil Brachyderes rugatus were also detected, broadly coinciding with the population expansions within the Canary Island pine forests. Given the estimated times of expansion, these population demographic increases would seem likely related to the process of colonisation of newly emerged islands or local patches after volcanic disturbance. Detection and dating of these expansions from chloroplast microsatellites was, to some degree, negatively affected by homoplasy (i.e. parallel and back mutations).<br /><br />Coalescent simulations of the evolution of chloroplast microsatellites were applied to study the effects of homoplasy in the statistical analysis of population structuring. Measures of genetic diversity based on number of haplotypes and genetic distances were differently affected. Genetic distances were underestimated but were proportional to the actual value. These effects help to explain the lower performance of statistical analyses for the detection and dating of population expansions. Further research on the effects of homoplasy in the analysis of population differentiation using chloroplast microsatellites is essential.

The analysis of craniometric data collected from skeletal remains, combined with archaeological data, can provide very valuable information pertaining to biological distance and gene flow among prehistoric populations through space and time. The goal of this study was to examine microevolutionary change among prehistoric populations in south Florida based on the degree of cranial variation among populations at seven prehistoric sites. It was expected that as time progressed, microevolutionary forces caused significant changes in the crania of the various populations based on the relative geographic proximity of the sites and the temporal distance between sites. A Microscribe 3-DX digitizer was used to collect coordinate data using the full protocol of cranial landmarks. Twenty-three interlandmark distances for n=223 skulls from seven sites, ranging in age from 8120 B.P. to 260 B.P., were analyzed using Cluster Analysis, an Analysis of Variance (ANOVA), a Tukey’s Pairwise Comparison (post-hoc test), a Multiple Analysis of Variance (MANOVA), and Principal Components Analysis (PCA) in SPSS 18.0. The seven sites were Windover (8Br246), Perico Island (8Ma6), Captiva Island (8Ll57), Belle Glade (8Pb40), Horr’s Island (8Cr41), Safety Harbor (8Pi2), and Fuller Mound A (8Br90). Of the 223 crania used, zero (0) skulls were 100% complete. Results of univariate and multivariate statistical analyses indicate that there are significant differences among the seven groups. The agglomerative cluster analysis did not provide significant results. When using Maximum Cranial Length (GOL), the ANOVA (F=5.190, p ≤ 0.000) and post-hoc tests indicated that there was a significant amount of variation among the seven populations. In a series of 12 MANOVA tests, it was determined that significant variation existed between Windover and each of the remaining six sites (F > 5, p ≤ 0.000). Additionally, the MANOVA tests indicated that significant variation existed between Horr’s Island and Safety Harbor (F = 8.151, p ≤ 0.000) and between Safety Harbor and Fuller Mound A (F = 5.549, p ≤ 0.000). Last, a Principal Components Analysis demonstrated that measurements consistent with length or breadth accounted for the largest percentage of variation among the populations. In conclusion, the data strongly demonstrate a significant amount of variation among prehistoric populations as time progressed from 8120 B.P. to 260 B.P. Specifically, changes in gene flow which can be attributed to significant differences among populations based on craniometric data parallel major time gaps and historical events in Florida. More generally, these results can be applied to other past populations to investigate similar patterns of gene flow and changes that may have occurred due to various social, political, and environmental stressors.