Search

Abstract Background Meat quality and composition traits have become valuable in modern pork production; however, genetic improvement has been slow due to high phenotyping costs. Combining genomic information with multi-trait indirect selection based on cheaper indicator traits is an alternative for continued cost-effective genetic improvement. Methods Data from an ongoing breeding program were used in this study. Phenotypic and genomic information was collected on three-way crossbred and purebred Duroc animals belonging to 28 half-sib families. We applied different methods to assess the value of using purebred and crossbred information (both genomic and phenotypic) to predict expensive-to-record traits measured on crossbred individuals. Estimation of multi-trait variance components set the basis for comparing the different scenarios, together with a fourfold cross-validation approach to validate the phenotyping schemes under four genotyping strategies. Results The benefit of including genomic information for multi-trait prediction depended on the breeding goal trait, the indicator traits included, and the source of genomic information. While some traits benefitted significantly from genotyping crossbreds (e.g., loin intramuscular fat content, backfat depth, and belly weight), multi-trait prediction was advantageous for some traits even in the absence of genomic information (e.g., loin muscle weight, subjective color, and subjective firmness). Conclusions Our results show the value of using different sources of phenotypic and genomic information. For most of the traits studied, including crossbred genomic information was more beneficial than performing multi-trait prediction. Thus, we recommend including crossbred individuals in the reference population when these are phenotyped for the breeding objective.

Abstract Background Egg production traits are economically important in poultry breeding programs. Previous studies have shown that incorporating genomic data can increase the accuracy of genetic prediction of egg production. Our objective was to estimate the genetic and phenotypic parameters of such traits and compare the prediction accuracy of pedigree-based random regression best linear unbiased prediction (RR-PBLUP) and genomic single-step random regression BLUP (RR-ssGBLUP). Egg production was recorded on 7422 birds during 24 consecutive weeks from first egg laid. Hatch-week of birth by week of lay and week of lay by age at first egg were fitted as fixed effects and body weight as a covariate, while additive genetic and permanent environment effects were fitted as random effects, along with heterogeneous residual variances over 24 weeks of egg production. Predictions accuracies were compared based on two statistics: (1) the correlation between estimated breeding values and phenotypes divided by the square root of the trait heritability, and (2) the ratio of the variance of BLUP predictions of individual Mendelian sampling effects divided by one half of the estimate of the additive genetic variance. Results Heritability estimates along the production trajectory obtained with RR-PBLUP ranged from 0.09 to 0.22, with higher estimates for intermediate weeks. Estimates of phenotypic correlations between weekly egg production were lower than the corresponding genetic correlation estimates. Our results indicate that genetic correlations decreased over the laying period, with the highest estimate being between traits in later weeks and the lowest between early weeks and later ages. Prediction accuracies based on the correlation-based statistic ranged from 0.11 to 0.44 for RR-PBLUP and from 0.22 to 0.57 for RR-ssGBLUP using the correlation-based statistic. The ratios of the variances of BLUP predictions of Mendelian sampling effects and one half of the additive genetic variance ranged from 0.17 to 0.26 for RR-PBLUP and from 0.17 to 0.34 for RR-ssGBLUP. Although the improvement in accuracies from RR-ssGBLUP over those from RR-PBLUP was not uniform over time for either statistic, accuracies obtained with RR-ssGBLUP were generally equal to or higher than those with RR-PBLUP. Conclusions Our findings show the potential advantage of incorporating genomic data in genetic evaluation of egg production traits using random regression models, which can contribute to the genetic improvement of egg production in turkey populations.

Abstract Background While the adoption of genomic evaluations in livestock has increased genetic gain rates, its effects on genetic diversity and accumulation of inbreeding have raised concerns in cattle populations. Increased inbreeding may affect fitness and decrease the mean performance for economically important traits, such as fertility and growth in beef cattle, with the age of inbreeding having a possible effect on the magnitude of inbreeding depression. The purpose of this study was to determine changes in genetic diversity as a result of the implementation of genomic selection in Angus cattle and quantify potential inbreeding depression effects of total pedigree and genomic inbreeding, and also to investigate the impact of recent and ancient inbreeding. Results We found that the yearly rate of inbreeding accumulation remained similar in sires and decreased significantly in dams since the implementation of genomic selection. Other measures such as effective population size and the effective number of chromosome segments show little evidence of a detrimental effect of using genomic selection strategies on the genetic diversity of beef cattle. We also quantified pedigree and genomic inbreeding depression for fertility and growth. While inbreeding did not affect fertility, an increase in pedigree or genomic inbreeding was associated with decreased birth weight, weaning weight, and post-weaning gain in both sexes. We also measured the impact of the age of inbreeding and found that recent inbreeding had a larger depressive effect on growth than ancient inbreeding. Conclusions In this study, we sought to quantify and understand the possible consequences of genomic selection on the genetic diversity of American Angus cattle. In both sires and dams, we found that, generally, genomic selection resulted in decreased rates of pedigree and genomic inbreeding accumulation and increased or sustained effective population sizes and number of independently segregating chromosome segments. We also found significant depressive effects of inbreeding accumulation on economically important growth traits, particularly with genomic and recent inbreeding.

La relación del sujeto con el conocimiento es una cuestión esencial en el marco del desarrollo acelerado de la ciencia y la tecnología, razón que ha instituido el aprender a aprender como uno de los pilares de la educación. Las formas de adquisición del conocimiento, son diversas, pero una de las más cotidianas y connaturales es la resolución de problemas. Un contexto tan complejo, en el que de forma acelerada se genera un enorme volumen de información, hace pensar en la necesidad de comprender y valorar el papel de la resolución de problemas como acto epistemológico, que favorece la incorporación de nuevos saberes al sistema de conocimientos del sujeto. Pero, ¿mediante qué procederes se propicia desde la docencia la resolución de problemas para que el estudiante alcance nuevos saberes? Se consultan diversas fuentes de información pertinentes al tema a la par que se muestran varias de las tendencias o perspectivas más sobresalientes en el tratamiento de la resolución de problemas como situación de aprendizaje y sus regularidades. Con este trabajo se expone una visión sintética de los recursos existentes para el tratamiento de la resolución de problemas desde un enfoque epistemológico, lo que propicia un mejor aprovechamiento de esta situación de aprendizaje orientado al aprender a aprender.

Heidegger, in his 1925 work, History of the Concept of Time: Prolegomena, provides a review of the phenomenological proposal within the philosophical tradition, recovering the discoveries through this research: intentionality, categorical intuition, and the original sense of the «a priori», as well as presenting the importance of the Husserl´s work for the development of the philosophical research. The concept of the categorical intuition becomes relevant for Heidegger, and is characteristic of his own research. What I intend to do here is to present an interpretation of this notion from the perspective of the world´s idea as the dimension of the constitution of the appearance of beings. As the world is a fundamental theme in the Heidegger’s phenomenology, I shall try to outline the way of understanding the world since the fundamental ontology, through attunement, Befindlichkeit in German. Therefore, I will be able to analyze the specificity of the Heidegger´s phenomenology, and at the same time demonstrate conceptual similarities between Heidegger and Husserl, by means of two concepts: reflection and epoché, but always in relation to the world.

Lonza began as a small Swiss electricity company and it has successfully adapted to change throughout its history to become a global custom manufacturing company serving the needs of the life-science industry. One of the crucial decisions and changes in its development was the implementation of biotechnology. This article outlines briefly the history of change during Lonza's development, some of the problems that confronted the chemical industry approximately a decade ago and how they affected the area of biotransformation. There are still many chemical reactions that are difficult, inefficient and environmentally unfriendly. Lonza believes that some of these problems can be solved by biotechnology if the biocatalytic platform can be widened and improved so that the biocatalysts can be easily integrated into a chemical process.