Estimation and utilization of inbreeding and dominaxce genetic Effects in genetic evaluation of purebred american swine

Genetic evaluation in swine is currently conducted utilizing additive genetic models. Historical studies have examined the relative influence of inbreeding on phenotypic performance; however, until recently estimation of dominance genetic effects fi-om large populations have proven prohibitive. Utilizing Method R, single-trait estimation of inbreeding and dominance genetic effects were conducted for a population of purebred American Yorkshire swine. The traits analyzed included number born alive (NBA), 21.day litter weight (LWT), days to 104.5 kg (DAYS), and backfat at 104.5 kg (BF). Dominance and inbreeding were found to have sizeable influence for the reproductive and growth traits analyzed. Subsequent analysis analyzed the changes in prediction of additive breeding values when including inbreeding or dominance and inbreeding effects in the genetic prediction model. Inbreeding had greatest influence on prediction of additive breeding value for inbred individuals or families. On average, inclusion of dominance genetic effects seemed to influence smaller changes

Nasal physiological changes during pregnancy

Rhinitis in pregnancy has been previously investigated with variable results. This study examines all the variables of the nasal airway simultaneously for the first time. Eighteen women were recruited in the first trimester of pregnancy and followed through to the postpartum period to monitor the changes that occurred. Measurements of the nasal airway included anterior rhinoscopy (AnR), peak inspiratory nasal flow, acoustic rhinometry, anterior rhinomanometry (ARM), and the saccharin test with rhinitis questionnaire scores providing a symptomatic measurement. All the tests showed a trend consistent with decreasing nasal patency when expressed as an average for the group as a whole, although only AnR, ARM, mucociliary clearance time and rhinitis questionnaire scores were statistically significant (P < or = 0.05). This confirms the effect of pregnancy on the nasal mucosa and coincides with the rise in the serum concentration of the female sex hormones with gestational age, returning to normal postpartum. Pharmacological antagonism of oestrogens may therefore relieve nasal congestion and is currently under further research

Comparação de métodos de seleção em populações simuladas de frangos de corte Comparison of selection methods in simulated populations of broilers

Populações de frangos de corte foram simuladas utilizando-se o programa GENESYS, com o objetivo de avaliar a seleção com base no método da melhor predição linear não-viesada (BLUP - best linear unbiased prediction), a seleção individual para três tamanhos efetivos de população e três sistemas de acasalamento dos reprodutores selecionados. Simulou-se um genoma constituído de uma característica quantitativa, com valor de herdabilidade igual a 0,30, em seleção praticada durante 15 gerações consecutivas, com 30 repetições por geração. Para um mesmo tamanho efetivo e sistema de acasalamento, o BLUP foi sempre superior à seleção individual nas 15 gerações de seleção avaliadas.<br>Populations of broilers were simulated by using the program Genesys, in order to evaluate the selection based on BLUP (best linear unbiased prediction), and the individual selection for three effective population sizes, and three mating systems of the selected reproducers. The simulated genome was constituted by a quantitative trait, which had heritability of 0.30, in a selection made during 15 consecutive generations, and 30 cycles for generation. BLUP was always superior to the individual selection during all generations evaluated with the same effective size and mating system

Seleção tradicional e associada a marcadores moleculares na avaliação genética animal Traditional and associated selection with molecular markers in the genetic evaluation of animals

O objetivo deste trabalho foi comparar a seleção, utilizando valores genéticos preditos pelo BLUP clássico (BLUP), BLUP marcadores (BLUPM) e pela seleção individual (SI), usando simulação com o programa Genesys. Para obter a matriz de similaridade genética utilizada no BLUPM, foram simulados cem marcadores moleculares do tipo microssatélite (SSR - Simple Sequence Repeat), por meio de um coeficiente de similaridade correspondente à distância euclideana média para dados quantitativos. A fim de comparar os diferentes métodos, utilizaram-se populações com tamanho efetivo de 66,66 e média de 30 repetições, avaliando-se os valores fenotípicos médios. Os ganhos ao longo das 20 gerações de seleção foram maiores para o BLUP em relação ao BLUPM, e este foi superior à SI. Quanto ao ganho obtido nas cinco primeiras gerações, o BLUPM apresentou ganhos semelhantes ao BLUP e superiores à SI. Diferentes sistemas de acasalamento dos reprodutores selecionados não revelaram diferenças em ganho genético nos métodos baseados no BLUP.<br>The objective of this work was to compare selection based on breeding values predicted by classical best linear unbiased prediction (BLUP), BLUP associated with molecular markers (BLUPM) and individual selection (IS) using data simulated with the Genesys program. To obtain the genetic similarity matrix to be used in BLUPM, a hundred microsatellite markers (simple sequence repeats) were simulated using a similarity coefficient corresponding to the mean Euclidean distance between quantitative data. The different selection methods were compared using populations of an effective size of 66.66 and a mean of 30 repetitions, and mean phenotypic values were determined. Genetic gain obtained over 20 generations of selection was higher for BLUP than BLUPM, which in turn was superior to IS. Similar genetic gains were obtained for BLUPM and BLUP only when the gain for the first five generations was considered, and these gains were higher than those obtained with IS. Selected reproducers mating systems did not lead to differences in genetic gain for the BLUP-based methods

Biosynthesis of secondary metabolites in sugarcane

A set of genes related to secondary metabolism was extracted from the sugarcane expressed sequence tag (SUCEST) database and was used to investigate both the gene expression pattern of key enzymes regulating the main biosynthetic secondary metabolism pathways and the major classes of metabolites involved in the response of sugarcane to environmental and developmental cues. The SUCEST database was constructed with tissues in different physiological conditions which had been collected under varied situation of environmental stress. This database allows researchers to identify and characterize the expressed genes of a wide range of putative enzymes able to catalyze steps in the phenylpropanoid, isoprenoid and other pathways of the special metabolic mechanisms involved in the response of sugarcane to environmental changes. Our results show that sugarcane cDNAs encoded putative ultra-violet induced sesquiterpene cyclases (SC); chalcone synthase (CHS), the first enzyme in the pathway branch for flavonoid biosynthesis; isoflavone synthase (IFS), involved in plant defense and root nodulation; isoflavone reductase (IFR), a key enzyme in phenylpropanoid phytoalexin biosynthesis; and caffeic acid-O-methyltransferase, a key enzyme in the biosynthesis of lignin cell wall precursors. High levels of CHS transcripts from plantlets infected with Herbaspirillum rubri or Gluconacetobacter diazotroficans suggests that agents of biotic stress can elicit flavonoid biosynthesis in sugarcane. From this data we have predicted the profile of isoprenoid and phenylpropanoid metabolism in sugarcane and pointed the branches of secondary metabolism activated during tissue-specific stages of development and the adaptive response of sugarcane to agents of biotic and abiotic stress, although our assignment of enzyme function should be confirmed by careful biochemical and genetic supporting evidence.<br>Este trabalho foi realizado com os objetivos de gerar uma coleção de genes relacionados ao metabolismo secundário da cana de açúcar e investigar o padrão de expressão gênica de enzimas chaves reguladoras das principais vias biossintéticas ativas nos diferentes tipos de tecidos e situações de estresse físico-químico e biológico a que estão submetidas plantas cultivadas em casas de vegetação, campo ou in vitro. A estratégia de mineração dos dados da database de sequências expressas de cana de açúcar, SUCEST, usando ferramentas de bioinformática, focalizou classes de compostos como isoprenóides e fenilpropanóides que comprovadamente desempenham um papel na resposta de plantas a variações ambientais. Foram identificados e caracterizados genes que codificam enzimas chaves para a síntese de terpenóides, como a sesquiterpeno ciclase (SC); (CHS) para síntese de flavonóides; isoflavona sintase (IFS) envolvida na biossíntese de isoflavonóides que desempenharm importante papel na defesa de plantas e nodulação de raízes; isoflavona redutases (IFR) enzimas chaves para a síntese de fenilpropanóide fitoalexinas, bem como enzimas relacionadas à síntese de precursores de lignina, como a enzima ácido caféico- O- metiltransferase. O efeito do estresse causado por bactérias como Herbaspirillum rubri e Gluconacetobacter diazotroficans também foi avaliado tendo sido constatada a indução da expressão de chalcona sintase (CHS) em plântulas infectadas com esses agentes, sugerindo a ativação da via de flavonóides em resposta a este estresse biológico. Esses resultados apontam para o fato de que as vias do metabolismo de isopropanóides e de fenilpropanóides em cana de açúcar são ativadas de acordo com o estágio de desenvolvimento, especificidade de tecidos e em resposta a situações de estresse. Essas observações deverão ser confirmadas por meio de experimentação genética e bioquímica