The overall accuracy, efficiency and profitability of livestock improvement strategies can be greatly increased by incorporating quantitative genetics into livestock selection and breeding. Since the introduction of quantitative genetics, a range of traits describing the animal e.g. in terms of health, growth, fecundity, production, have been extensively evaluated in terms of genetics and are now commonly manipulated through breeding to achieve specific selection goals. An industry led enquiry as to the possibility of including spine traits in genetic selection to increase back length in sheep was the basis of the present thesis. Collecting information on spine traits (spine length, vertebrae length and vertebrae number) is of particular interest and use to the sheep breeding industry as there may be the potential to increase meat yield from the highly valuable longissimus thoracis et lumborum (LTL or loin), located parallel to the spine, with little associated change in production costs. The thesis focusses on the use of X-ray computed tomography (CT) scanning as a technique which would allow spine traits to be measured in vivo, hence being useful for genetic selection. The topogram scans produced from the CT scanning procedure were analysed to derive spine trait information for the thesis. The scans were from Scottish Blackface (maternal breed stock), Texel (terminal sire breed), Texel cross Mule and Poll Dorset cross Mule (three-way cross slaughter lambs) so as to represent the divergent genotypes found across the different levels of the United Kingdom’s (UK) three-tier crossbreeding structure of sheep. The present study explored as a first step intra- and inter-operator repeatability of assessment of spine traits from CT derived topograms, as a means to investigate the suitability of the approach for widespread uptake within industry where operators will vary. The results showed that there was high repeatability for intra- and inter-operator assessment of spine trait measurements verifying that the CT method could be accepted as a reliable alternative (to slaughter for example) to quantify spine traits. To determine whether spine traits are similar across the range of breeds representing the key genotypes and crosses in the UK sheep industry, numerous CT topograms were analysed. The results showed marked variation in spine traits within and between Scottish Blackface, Texel, Texel cross Mule and Poll Dorset cross Mule breeds and crosses. For example, the Texel breed was found to have the largest within-breed range for thoracolumbar vertebrae number (17 – 21; the majority possessing 19), but the spine length of these animals was, on average, significantly shorter than the other breed/cross groups. The present study concluded that the significant differences between the breeds and breed types for the particular spine traits were possibly indicative of a genetic control for these traits. Furthermore, investigation into the phenotypic correlations between spine and production traits revealed some directional associations which may prove beneficial for meat production. For example, Scottish Blackface lambs which had a longer length of a specific spine region had an associated decrease in the volume of carcass fat. Texel lambs which had a longer length of a specific spine region had a slightly larger loin muscle area, at a given weight. The present study also examined animals from a population of Texel lambs already heavily selected for increased muscling. The Texel muscling quantitative trait locus (TM-QTL), segregating in these animals and generally in the UK’s Texel sheep population, is expressed through a polar overdominance pattern of inheritance and its effect on the loin (localised muscle hypertrophy) is commonly utilised in the selection and breeding of Texel sheep to improve meat production. Examination of topograms from lambs bearing the whole range of TM-QTL genotypes showed little evidence to suggest that the change in loin shape/increased loin muscling, as a result of the TM-QTL and its inheritance, has led to any associated change in the underlying spine characteristics. This suggests that selection for increased muscling associated with the TM-QTL may be achieved independently of changes in the spine traits studied. The potential to breed for certain spine traits to increase vertebrae number and hence chops or loin yield can be enhanced by establishing the genetic parameters for the traits. The present study employed a collection of performance trait records from Texel lambs to provide the basis for genetic analysis. The results showed different levels of heritability for the different spine traits but also high standard errors. For example, heritability of vertebrae number was dependent on vertebra location: for thoracic vertebrae heritability was high (ℎ2 = 0.99; SE = 0.42), for lumbar vertebrae heritability was low (ℎ2 = 0.08; SE = 0.12), whereas in contrast, thoracolumbar vertebrae heritability was moderate (ℎ2 = 0.44; SE = 0.27). Phenotypic and genetic correlations between all combinations of traits were also obtained. Accurate predictions of the size and direction of response to selection can be achieved through such genetic analysis of traits. The more that is known of the genetic characteristics of traits and their genetic correlations with other economically important traits, the more efficiently it can be built into breeding programmes improving the overall performance of stock. The results of this study showed that providing spine measurements can contribute to the diversity of trait information available to breeders. The present study also suggests that there may be opportunities to select for increased spine length/vertebrae number which would benefit the sheep industry in terms of increased chop number/loin yield. Although more data are needed prior to implementation. Practical uptake of selection for spine traits would be enhanced due to the straightforward nature of the measurements and the high operator repeatability.

Made available in DSpace on 2014-06-11T19:29:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-23Bitstream added on 2014-06-13T20:39:10Z : No. of bitstreams: 1 arantes_fc_me_ilha.pdf: 1168321 bytes, checksum: ea63f91d3265eeb7fda8cc1c3380e584 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Clones com alta produtividade, adaptabilidade e estabilidade a vários ambientes são imprescindíveis para o desenvolvimento da heveicultura no Brasil. O objetivo do trabalho foi selecionar progênies com maior adaptabilidade e estabilidade a partir do diâmetro da planta a 50 cm do solo (DA50) e a produção de borracha seca (PBS, a partir do teste Hamaker Morris Mann modificado), de uma população de seringueira, aos três anos de idade, plantada em três ambientes distintos (Selvíria-MS, Votuporanga-SP e Colina-SP), utilizando-se do método MHPRVG (média harmônica da performance relativa dos valores genéticos) preditos por BLUP e estimar a variabilidade genética a partir de caracteres quantitativos, tais como: altura da planta (ATP), DA50, forma da planta (FOP), sobrevivência das progênies (SOP) e PBS dos três locais, aos dois e três anos de idade, pelo procedimento REML/BLUP visando a conservação dos recursos genéticos da espécie. As sementes utilizadas na produção das mudas dos testes de progênies foram, na sua maioria, coletadas de clones de origem Asiática provenientes da coleção de clones instalada na área experimental da Agência Paulista de Tecnologia dos Agronegócios – APTA - Polo Regional de Votuporanga, Estado de São Paulo. As progênies foram instaladas nos três locais sob o delineamento de blocos ao acaso, compostos por 30 tratamentos (progênies), três repetições e parcelas lineares de 10 plantas, no espaçamento de 3,00 x 3,00 metros, totalizando 900 plantas úteis em cada local. O método da MHPRVG propiciou um ganho genético de 12,03 a 45,65% entre 10 progênies selecionadas a partir da PBS e permitiu a seleção de progênies com alto potencial produtivo predito. As 10 melhores progênies foram oriundas dos clones GT1, PB 28/59, PR 261, RRIM 606, PB 217, IAC 41, IAC 35, PR 255, RRIM 701 e IAC 301. Os caracteres ATP, DA50, FOP, SOP e a PBS... / Clones with high yield, adaptability and stability for many environments are indispensables to the development of the rubber tree crop in Brasil. The paper objective was to select progenies with high adaptability and stability from the diameter gauges from 50 cm of height of soil (DA50) and dry rubber yield (PBS, from the Hamaker Morris Mann modified test), of genotypes from a rubber tree population, two and three years old, installed in three different locations (Selvíria-MS, Votuporanga-SP e Colina-SP), by the MHPRVG (Harmonic Average Performance Relative breeding values) method predicted by BLUP and to estimate the genetic variability from quantitative characters: total height of the plant (ATP), DA50, plant form (FOP), survival of progeny (SOP) and PBS of three locations, two and three years old, by REML/BLUP procedure, intending the genetic resources conservation of the specie. The seeds used on seedlings production of progenies tests were in majority collected on Asiatic clones origin from the clones installed in the experimental area of Agência Paulista de Tecnologia dos Agronegócios – APTA – Votuporanga regional pole, State of São Paulo. The progenies were installed in a randomized block design of 30 treatments (progenies), three replications and 10 plants per plot, with spacing of 3,00 x 3,00 m, a total of 900 useful plants in each location. The method of MHPRVG provided a genetic gain ranging from 12,03 to 45,65% in 10 progenies to the PBS and allowed the selection of progenies with high yield potential predicted. The 10 best progenies were derived from clones GT1, CR 28/59, PR 261, RRIM 606, PB 217, IAC 41, IAC 35, PR 255, RRIM 701 and IAC 301. The characters ATP, DA50, FOP, SOP and PBS presented considerable coefficients of genetic variation, ranging from 1,25% for the ATP to 21,33% for PBS and medium heritability for DA50 and PBS being 0,23 and 0,80, respectively... (Complete abstract click electronic access below)

O presente trabalho teve como objetivo avaliar a possível relação entre a temperatura alta e o provável aumento de tolerância à deficiência hídrica, bem como identificar e selecionar as linhagens celulares de Eucalyptus urophylla sob os aspectos fisiológicos e bioquímicos. Para isso, calos oriundos de hipocótilos de Eucalyptus urophylla mantidos em cultura de tecidos em meio de cultura N7 (SIMOLA, 1985) com 5 mg L-1 de Picloram foram utilizados para conduzir os testes. Estes calos foram submetidos a uma pressão de seleção em meio N7 (SIMOLA, 1985) suplementado com 20% de polietilenoglicol (PEG 6000) e em seguida, eles foram tratados em diferentes temperaturas (25, 30, 35, 40 e 45ºC) por duas horas em BOD. Então, esses frascos foram mantidos por vinte dias sob condições constantes de luz (50 µmol m-2 s-1 PAR) e temperatura de 26 + 2 oC com fotoperíodo de 12 horas. Após esse período, parte do material foi avaliada e o restante foi transferido para meio de cultura N7 suplementado com 5 mg L-1 de Picloram. Decorrido quatro meses, parte das linhagens sobreviventes à primeira seleção foram transferidas para o meio N7 líquido, visando avaliar a capacidade de recuperação do material. O restante dos calos selecionados foi novamente submetido aos estresses hídrico e térmico, conforme o tratamento realizado anteriormente, por vinte dias. Para avaliação das três etapas do experimento (primeira seleção, recuperação e segunda seleção), foram feitas determinações do teor de prolina, proteínas totais solúveis e carboidratos não-estruturais solúveis (ácido glucorônico, celobiose, glicose, poliose e arabinose), bem como avaliação do crescimento através da medição do peso seco e peso fresco. Os resultados foram avaliados por análise fatorial utilizando técnicas de componentes principais (PCA) e pela comparação de médias de acordo com a Análise de Variância (ANOVA) e LDS (Least Significant Difference). Assim, verificou-se que em primeira instância, altas temperaturas podem aumentar a tolerância a posterior deficiência hídrica, mas numa segunda exposição essa vantagem não é significativa. Além disso, linhagens tolerantes a condições de estresse podem ser selecionadas utilizando essa metodologia. / This work aimed to assess a possible relation between hight temperature and improvement in drought tolerance, as well as identify and select Eucalyptus urophylla cell lines under physiological and biochemical aspects. Callus obtained from hypocotyl of Eucalyptus urophylla and cultivated in N7 medium (SIMOLA, 1985) with the addition of 5mg.L-1 of Picloram were used to carry out the tests. These callus were transferred to N7 medium (SIMOLA, 1985) suplemented with 20% of PEG 6000 and then, they were treated at different temperatures (25, 30, 35, 40 and 45ºC) for two hours in BOD. Then, they were kept under constant conditions of light (50 µmol m-2 s-1 PAR) and temperature (26 + 2 oC) with photoperiod of 12 hours for 20 days. After that, part of the material was evaluated and the remained callus was transferred to N7 medium supplemented with 5 mg L-1 of Picloram. Passed four mouths, half of the selected cell lines was transferred to N7 liquid medium, aiming to evaluate the capacity of recovery of the material. The other part of the selected callus was submitted to water and thermal stress again, as in the first selection, for 20 days. The evaluation of the callus response was made through the quantification of proline, total soluble proteins, soluble sugars (glucoronic acid, glucose, celobiose, poliose and arabinose). The data were analised through fatorial analises using principal component techinics and through means comparation according to ANOVA and LSD (Least Significance Difference) test. Thus, these results showed a positive relation between hight temperature and improvement in drought tolerance in first instance, but in a second exposition to this stress factor, these advances was not significant. Tolerant cell lines to stress conditions could be selected using this methodology.

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No. of bitstreams: 2 Dissertação - Ligia da Cunha Moreira - 2014.pdf: 1675032 bytes, checksum: abbce36de279a092b9f81566a296fbc8 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Genetic selection of animals with potential for improved carcass and meat quality is a strategy that should be employed in Brazilian livestock. The country occupies a prominent position in global agribusiness, possessing the largest commercial cattle herd in the world and being one of the largest exporters of beef. However, Brazilian beef is classified as medium to low quality. The aim of the present study was to evaluate quantitative and qualitative characteristics of the carcass and beef in Polled Nellore belonging to a segregating population selected for meat tenderness. There were 68 male animals, with age average six months and initial weights 215.5 kg. The animals were slaughtered when they reached a minimum weight of 500 kg and 5 millimeters of fat backfat, forming groups of 17 or 18 animals of each slaughter. The slaughter occurred in a commercial slaughterhouse under Federal Inspection (SIF 431). The experimental design was a randomized block design with two treatment types (low and high WBSF). Data were subjected to an analysis of variance using the GLM procedure in SAS. The treatment means were compared by the Duncan test at 5% significance. Sensory analyses were submitted to the NPAR1WAY procedure, and means were compared by the non-parametric Kruskal- Wallis test. There weren’t significant differences for the carcasses characteristics evaluated. The shear force was high for animals with high WBSF analyzed in both methods (1.55 kgf and 2.48 kgf texturometer Warner Bratzler). The high group WBSF had a value of 5.99 for pH, higher than the low group WBSF, which showed a pH of 6.36. The animals of the low WBSF group had lower cooking losses, 18.1% and higher water retention capacity of 77.01%. It is suggested that these differences may have been due to the high pH value observed for animals in this group. Color parameters were better for animals with high WBSF. In the sensory panel, the animals with low WBSF were better for both, tenderness (8.38 vs. 5.01) and juiciness (6.12 vs. 5.26), compared to the high WBSF group. The two groups did not differ in carcass characteristics, but animals with low WBSF produced superior beef according to objective and taste panel evaluations. Genetic selection for meat tenderness didn’t influence carcass characteristics, but was effective / A seleção genética de animais com potencial para produção de carcaça e carne de melhor qualidade é uma estratégia que deve ser mais adotada pela pecuária brasileira. O país ocupa posição de destaque no agronegócio mundial, detentor do maior rebanho bovino comercial do mundo, e um dos maiores exportadores de carne bovina, no entanto, a carne brasileira é tida como de média a baixa qualidade. Objetivou-se avaliar as características quantitativas e qualitativas da carcaça e da carne de bovinos Nelore Mocho, pertencentes a uma população segregante selecionada para maciez da carne. Foram utilizados 68 animais machos inteiros sendo 27 deles pertencentes ao grupo de baixo WBSF (força de cisalhamento <3,5 kgf) e 41 pertencentes ao grupo de alto WBSF (força de cisalhamento >3,5 kgf). A idade e peso inicial dos animais foram, em média de seis meses e 215,5 kg, respectivamente. Os animais foram abatidos quando atingiram peso mínimo de 500 kg e cinco milímetros de espessura de gordura, formando grupos com 17 ou 18 animais por abate. O abate ocorreu em frigorifico comercial sob Inspeção Federal (SIF 431). O delineamento experimental foi em blocos casualizados com dois tratamentos (baixo e alto WBSF). Os dados foram submetidos à análise de variância utilizando o procedimento GLM, disponibilizados no programa estatístico SAS. As médias dos tratamentos foram comparadas pelo teste de Duncan a 5% de significância. As análises sensoriais foram submetidas ao procedimento NPAR1WAY, e as médias foram comparadas pelo teste não paramétrico de Kruskal-Wallis. Não houve diferença significativa para as características de carcaça avaliadas. A força de cisalhamento foi menor para os animais de baixo WBSF nos dois métodos analisados (1,55 kgf no texturômetro e 2,48 kgf no Warner Bratzler). O grupo de alto WBSF apresentou valor médio de 5,99 para pH, sendo superior ao grupo baixo WBSF, que apresentou pH de 6,36 em média. A carne dos animais de baixo WBSF apresentam menores perdas por cocção (18,1%) e maior capacidade de retenção de água (77,01%), sugere-se que essas diferenças possam ter sido devido ao alto valor de pH observado para os bovinos deste grupo. Os parâmetros de cor foram superiores para os animais de alto WBSF. No painel sensorial, a carne dos animais de baixo WBSF foram superiores, tanto para a característica de maciez (8,38 vs. 5,01) como para suculência (6,12 vs. 5,26), em relação ao grupo alto WBSF. Os dois grupos não diferiram em relação às características de carcaça, mas a carne dos animais de baixo WBSF apresentaram superioridade para as características de qualidade medidas objetivamente pelo painel sensorial. Dessa forma, pode-se afirmar que a seleção genética para maciez da carne não influenciou nas características de carcaça, mas foi eficiente na melhoria das características de qualidade da carne proveniente de bovinos da raça Nelore.

O conhecimento dos diferentes fatores genéticos que afetam os caracteres quantitativos de importância agronômica é um pré-requisito importante para o planejamento dos programas de melhoramento genético que visam explorar de maneira eficiente a variabilidade genética disponível nas populações. A importância da epistasia no melhoramento genético das populações de milho ainda não é bem entendida, sendo assim ignorada na maioria dos estudos de herança dos caracteres de interesses para os melhoristas. Os objetivos deste trabalho foram: (i) verificar a importância da epistasia para produção de grãos e seus componentes em milho; (ii) estimar os efeitos epistáticos em cada planta F2 para estes caracteres; e (iii) verificar a importância da interação epistasia x ambientes. A geração F1 obtida do cruzamento entre as linhagens endogâmicas L08-05F e L38-05D foi autofecundada para dar origem à população F2. Uma amostra de 100 plantas F2 foi autofecundada originando 100 progênies F2:3, que foram retrocruzadas com ambas as linhagens genitoras e sua geração F1, seguindo o esquema de cruzamento do delineamento triple test cross (TTC). As 300 progênies de retrocruzamentos foram avaliadas em 11 ambientes no município de Piracicaba/SP, em delineamento alfa-látice 15 x 20, no esquema fatorial com duas repetições por ambiente. As análises de variância seguindo o modelo TTC mostraram que a epistasia total foi altamente significativa para todos os caracteres e que os efeitos epistáticos não aditivos (epistasia aditiva x dominante e/ou dominante x dominante) foram mais importantes que a epistasia aditiva x aditiva. Os efeitos epistáticos estimados em cada planta F2 para a produção de grãos e seus componentes não foram unidirecionais e, além disso, sugerem a presença de epistasia pleiotrópica para PG e a maioria dos componentes da produção. A interação epistasia x ambientes foi verificada apenas para o caráter número de fileiras espigas-1. A presença de efeitos epistáticos positivos poderiam estar contribuindo significativamente para a elevada heterose reportada para o cruzamento entre as linhagens L08-05F x L38-05D. Os resultados sugerem que a epistasia é um componente importante na arquitetura genética dos caracteres estudados, o que significa que o modelo aditivo dominante não é suficiente para descrever a variação genética da produção de grãos e seus componentes na população. Diante disso, os efeitos epistáticos não deveriam continuar sendo ignorados e sua consideração nos modelos de predição da performance dos genótipos e na seleção assistida por marcadores moleculares poderia aumentar significativamente a eficiência da seleção nos programas de melhoramento genético de plantas. / Knowledge of different genetic factors that affect quantitative traits of the agronomic importance, is an relevant prerequisite to plant breeding programs aiming to efficiently explore the genetic variability available in populations. The importance of epistasis in breeding populations of maize is still not well understood, being ignored in most inheritance studies of characters important to plant breeders. This study aimed (i) to verify the role of epistasis in grain yield and its components in maize, (ii) to estimate the epistatic effects in each F2 plant for these characters, and (iii) to verify the role of epistasis x environment interaction. The F1 generation was developed from the cross between the inbred lines L-08-05F and L-38-05D and the F2 population from the selffecundated of F1. A sample of 100 F2 plants was self-fecundated resulting in 100 F2:3 progenies, which were backcrossed with both parental lines and their F1 generation, according to the triple test cross (TTC) design. The 300 backcross progenies were evaluated in 11 environments at the municipality of Piracicaba-SP, Brazil, using an alpha-lattice 15 x 20 design in a factorial arrangement with two replications per environment. Analysis of variance based on the TTC model showed that the total epistasis was highly significant for all characters and that non-additive epistatic effects (additive x dominant and / or dominance x dominance) were more important than the additive x additive epistasis. The epistatic effects estimated in each F2 plant for grain yield and its components were not unidirectional and these estimates suggest the presence of pleitropic epistasis for yield and major yield components. The epistasis x environment interaction was observed only for the number of row eras-1. The presence of positive epistatic effects could contribute significantly to the high heterosis reported for the crossing between the inbred lines L08-05F x L38-05D. Results suggest that epistasis is an important component in the genetic architecture of the traits considered, which means that the additive - dominant model is not enough to describe the genetic variation of grain yield and its components in the population. Thus, the epistatic effects should not remain ignored and its account in the models for predicting performance of the genotypes and in the molecular marker-assisted selection would significantly increase the efficiency of selection programs in plant breeding.

As sequencing technology continues to produce better quality genomes at decreasing costs, there has been a recent surge in the variety of data that we are now able to analyze. This is particularly true with regards to our understanding of the human genome—where the last decade has seen data advances in primate epigenomics, ancient hominid genomics, and a proliferation of human polymorphism data from multiple populations. In order to utilize such data however, it has become critical to develop increasingly sophisticated tools spanning both bioinformatics and statistical inference. In population genetics particularly, new statistical approaches for analyzing population data are constantly being developed—unfortunately, often without proper model testing and evaluation of type-I and type-II error. Because the common Wright-Fisher assumptions underlying such models are generally violated in natural populations, this statistical testing is critical. Thus, my dissertation has two distinct but related themes: 1) evaluating methods of statistical inference in population genetics, and 2) utilizing these methods to analyze the evolutionary history of humans and our closest relatives. The resulting collection of work has not only provided important biological insights (including some of the first strong evidence of selection on human-specific epigenetic modifications (Shulha, Crisci, Reshetov, Tushir et al. 2012, PLoS Bio), and a characterization of human-specific genetic changes distinguishing modern humans from Neanderthals (Crisci et al. 2011, GBE)), but also important insights in to the performance of population genetic methodologies which will motivate the future development of improved approaches for statistical inference (Crisci et al, in review).

[pt] No presente estudo, foi investigada a ocorrência da resposta de congelamento de defesa durante o período pré- e pós-choque empregado no protocolo para a criação seletiva das linhagens de ratos Cariocas alto- e baixo-congelamento condicionado na PUC-Rio. Além disso, para obter uma maior clareza da estrutura deste comportamento defensivo e sua relação com as duas linhagens, foi realizada uma extração de componentes. Foram detectadas diferenças significativas entre as linhagens nos períodos pré- e pós-choque, com a diferença no período pré-choque sendo proporcional à encontrada no fenótipo. A análise fatorial revelou 4 componentes, o primeiro relacionado ao fenótipo, o segundo à parcela final do período pré-choque, o terceiro ao período pós-choque e o quarto à parcela inicial do período pré-choque. Estes resultados demonstram que o protocolo empregado foi capaz de produzir diferenças significativas nas linhagens selecionadas para alto e baixo congelamento condicionado em paradigmas de ansiedade incondicionada, indicando um mutualismo genético por trás destes mecanismos, observado pela primeira vez com ratos selecionados apenas pelo medo contextual condicionado. O componente que carregou a parcela final do período de habituação (pré-choque) mostrou-se mais responsável por explicar a variação individual do que a parcela inicial ou o pós-choque, indicando que este período dos minutos 5 a 8 é um intervalo ideal para obter de forma mais eficaz o traço comportamental do animal. / [en] The present study investigated freezing behavior patterns during the selective breeding protocol employed in the creation of the Cariocas High- and Low- Conditioned Freezing in PUC-Rio s Neuroscience Laboratory. There were significant differences found in the baseline, post-shock and retrieval (phenotype) freezing means of the High-, Low- and Control lines over the generations of selective breeding. A Principal Component Analysis of the freezing means in each minute of the contextual fear conditioning protocol revealed four components, the First loading the freezing in the retrieval period, the Second the final half of the baseline period, the Third loads the 3 minutes of freezing measured after foot shocks are received and the Fourth loads the first half of the baseline period. The analysis of the means shows that the selective breeding protocol employed successfully produced differences in anxiety in the selected lines. It s the first time this baseline difference in freezing is observed in Rats. Indicates that there s a genetic pleiotropy behind the underlying mechanisms that allow for a stronger or smaller fear response in response to contextual cues, conditioned or unconditioned. We hypothesize that this might be related to genetic differences in fear related spatial learning modulated by the selection process. Finally, the Second component loading the final half of the baseline period shows that this period (between 5 and 8 minutes) is better at producing a stable behavior pattern which more aptly reproduces the rat s individual identity.

In eubacteria, ribosome stalling on broken messenger RNA transcripts can lead to cell death. The trans-translation quality control mechanism rescues many of these stalled ribosomes. In this process, tmRNA enters stalled ribosomes by mimicking a transfer RNA, accepting the stalled nascent peptide. The ribosome then releases the broken mRNA and resumes translation on a coding region within tmRNA itself. Translation of tmRNA marks the nascent peptide for destruction by the addition of a short proteolysis tag and the ribosome is released at a stop codon within the tmRNA open reading frame. An intriguing aspect of trans-translation is that the ribosome synthesizes one protein from two RNA templates. How is the proper site chosen on tmRNA to resume translation? Do the conserved pseudoknot structures help set the reading frame? Using a genetic selection to assay libraries of tmRNA mutants, we found that stable hairpin structures can functionally replace pseudoknot 1. We conclude that the role of pseudoknot 1 in tmRNA function is purely structural. Our results demonstrate that the inactivity of an RNA mutant designed to destroy a given structure should not be interpreted as proof that the structure is necessary for RNA function. Such mutations may only destabilize a global fold that could be formed equally well by an entirely different, stable structure. Broken mRNAs are not the only cause of ribosome stalling; stalling can also result from nascent peptide interactions with the ribosomal exit tunnel that inhibit peptidyl-transferase activity. SecM, TnaC, and ErmCL all stall ribosomes to regulate the expression of downstream genes. What other peptide sequences can cause ribosome stalling? We modified our tmRNA-based selection to screen libraries of random peptides and identified a number of novel stalling peptides, including the sequence FxxYxIWPP. This sequence interacts with the exit tunnel differently than SecM and TnaC as seen in studies using mutant ribosomes. Like SecM, stalling occurs on this sequence with the next aminoacyl tRNA trapped in the A site but unable to react with the nascent peptide. These results show that a variety of peptides can interact in the exit tunnel and peptidyl-transferase center to regulate ribosome activity.

Que l’on parle de « technosemen », de « cyborg babies » ou de « techno-birth », force est de constater que le recours aux nouvelles technologies de reproduction participe d’une reconfiguration des processus biologiques. On assiste à une technicisation du corps qui entraine sa parcellisation et rend possibles son exploitation et sa commercialisation en pièces détachées. Or, la mise en valeur des substances biologiques est souvent accompagnée de leur rematérialisation dans l’imaginaire social. En nous intéressant à l’industrie du don de gamètes, nous cherchons à comprendre comment elle marchandise les substances reproductives en reconstituant le corps du donneur. La littérature est abondante sur la participation des nouvelles technologies de reproduction au renouveau identitaire et sociétal. Nous souhaitons donc décaler le regard et réfléchir sur la manière avec laquelle la sélection génétique opérée en clinique de reproduction nous révèle des schémas sociaux qui interviennent dans la dimension identitaire du corps. Dans le cadre de ce mémoire, il s’agira d’analyser les discours entourant le recrutement et la présentation des donneurs sur les sites internet de banques de gamètes au Canada et aux États-Unis. Nous montrerons que l’industrie du don de sperme et d’ovules, qui s’insère dans ce que l’on appelle la bioéconomie, participe à la reproduction d’une vision des formations sociales qui est à la fois genrée, racialisée et stratifiée par classes sociales. / Whether we talk about “technosemen”, “cyborg babies” or “techno-birth”, it all comes down to one thing: the use of the latest reproductive technologies is part of a redesign of the biological processes. What we are witnessing is that the body is being technified and ultimately broken down in such a way that it can be exploited and marketed in spare parts. However, because they’re being valued, the biological substances are often also rematerialized in the social consciousness. In looking at the gamete donation industry, we are trying to understand how it treats the reproductive substances as commodities in reconstructing the donor’s body. There is plenty of literature on how the new reproductive technologies are contributing to the identity and societal renewal. Our goal is therefore to look beyond and reflect on how much the genetic selection performed in fertility clinics says about the social patterns that enter in the identity dimension of the body. This thesis analyses the rhetoric used on the websites of sperm and egg banks in Canada and in the United States to recruit and present the donors. We will show that sperm and egg donations, which come within what is now called the bioeconomy, replicate a certain vision of social groups which are altogether classified by gender, race and social class.

Há tempos os melhoristas tentam prever as performances de híbridos a partir de informações das suas linhagens parentais. A aplicação mais promissora dos marcadores moleculares no melhoramento de plantas é sua utilização na seleção. A produção de grãos é o caráter de maior interesse para os melhoristas e caracteriza-se por ser controlado por grande número de locos, sofrendo acentuado efeito ambiental. Ela é função direta dos seus componentes e, como esses caracteres são correlacionados com a produção, eles podem ser utilizados na seleção indireta para aumentar a produção. Os objetivos desse estudo foram: estimar coeficientes de correlação entre linhagens S1 de milho e seus testecrosses; mapear QTL e verificar a congruência destes nas linhagens e nos testecrosses; obter médias preditas das linhagens com base em informações de marcadores moleculares; e verificar a possibilidade de selecionar testecrosses com base nas médias preditas das linhagens, para diversos caracteres. Foram avaliadas 256 linhagens S1 e 512 testecrosses dessas linhagens com dois testadores, em experimentos em látices simples 16x16 em seis ambientes. Foram avaliados os caracteres produção de grãos, acamamento e quebramento, florescimento masculino e feminino, intervalo entre florescimentos, altura da planta e da espiga, posição relativa da espiga, e os componentes da produção nas linhagens. Para o mapeamento de QTL nas linhagens e nos testecrosses foi utilizado um mapa genético com 177 marcadores microssatélites e o modelo de mapeamento por intervalo composto expandido para múltiplos ambientes. Além das médias fenotípicas das duas gerações, foram obtidas médias preditas das linhagens com base nos efeitos dos QTL e também com base em todos os marcadores do genoma. Os coeficientes de correlação entre as médias fenotípicas das linhagens e dos testecrosses variaram de reduzidos para produção de grãos até moderados para os caracteres de ciclo e estatura. Considerando os componentes da produção das linhagens e a produção dos testecrosses, a maioria das correlações não foram significativas e, quando foram, as magnitudes destas foram baixas. A congruência de QTL detectados nas linhagens e nos testecrosses foi pequena para todos os caracteres considerados. As correlações entre as médias preditas das linhagens e as médias fenotípicas dos testecrosses apresentaram resultados semelhantes àqueles obtidos considerando as médias fenotípicas das linhagens. As maiores coincidências de linhagens S1 e testecrosses superiores selecionados foram observadas para os caracteres de ciclo e estatura e, as menores, ocorreram para produção de grãos e seus componentes. Portanto, mesmo utilizando-se informações de marcadores moleculares, só é possível prever a performance de testecrosses a partir de informações das linhagens para os caracteres menos complexos e com reduzido efeito de dominância, além de não ser possível praticar seleção indireta para a produção dos testecrosses baseada nos componentes das linhagens. Nestes casos, as informações dos marcadores devem ser obtidas diretamente nos testecrosses. Mesmo utilizando informações de marcadores, a seleção pode ser iniciada durante a obtenção das linhagens para alguns caracteres mas, para outros, a seleção deve ser realizada pela avaliação das linhagens em cruzamentos. / For a long time breeders have been trying to predict the performance of hybrids based on the performance from their parental lines. The most promising application of molecular markers in plant breeding is their use in selection. Grain yield is the most important trait to breeders and it is controlled by a large number of loci undergoing accentuated environmental effect. It is a direct function of its components and as these traits are correlated with yield, they can be used for indirect selection to increase grain yield. The objectives of this research were to estimate correlations between S1 maize lines and their testcrosses; map QTL and verify its congruence in lines and testcrosses; predict means of the lines by using information from molecular markers; and verify the possibility to select testecrosses from the predict means of the lines for several traits. Two-hundred and fifty six S1 lines and five-hundred and twelve testcrosses of these lines with two testers were evaluated in simple lattice 16x16 design in six environments. The traits analyzed were grain yield, plant lodging, days to anthesis, days to silking, anthesis-silking interval, plant and ear height, ear placement, and the yield components in the lines. A genetic map with 177 microsatellite markers and the multiple-environmental composite interval mapping model were used to map QTL in the lines and in their testcrosses. In addition to the phenotypic means of the two generations, the predicted means of the lines based on QTL effects and based in all markers were obtained. The correlation coefficients between the phenotypic means of the lines and of the testcrosses ranged from low to grain yield to moderate for cycle and stature traits. Considering the grain yield components of the lines and yield of the testcrosses, most of the correlations were not significant and, when they were, their magnitudes were low. The congruence of QTL detected in the lines and testcrosses were small for all traits. The correlations between the predict means of the lines and the phenotypic means of the testcrosses showed similar results with those obtained by the lines phenotypic means. The highest coincidences of selected superior S1 lines and testcrosses were observed for cycle and stature traits and the lowest for grain yield and its components. Therefore, even by using molecular markers information, it is only possible to predict the testcrosses performance from the lines information to less complex traits and with small dominance effects, as well as not being possible to carry out indirect selection to testcrosses yield based on the components of the lines. For these cases, the markers information must be obtained directly from the testcrosses. Even by using markers information, selection may be initiated during lines development for some traits, but to others, the selection must be made by evaluation of the lines in crosses.