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Abstract Background The high fecundity of fish species allows intense selection to be practised and therefore leads to fast genetic gains. Based on this, numerous selective breeding programmes have been started in Europe in the last decades, but in general, little is known about how the base populations of breeders have been built. Such knowledge is important because base populations can be created from very few individuals, which can lead to small effective population sizes and associated reductions in genetic variability. In this study, we used genomic information that was recently made available for turbot (Scophthalmus maximus), gilthead seabream (Sparus aurata), European seabass (Dicentrarchus labrax) and common carp (Cyprinus carpio) to obtain accurate estimates of the effective size for commercial populations. Methods Restriction-site associated DNA sequencing data were used to estimate current and historical effective population sizes. We used a novel method that considers the linkage disequilibrium spectrum for the whole range of genetic distances between all pairs of single nucleotide polymorphisms (SNPs), and thus accounts for potential fluctuations in population size over time. Results Our results show that the current effective population size for these populations is small (equal to or less than 50 fish), potentially putting the sustainability of the breeding programmes at risk. We have also detected important drops in effective population size about five to nine generations ago, most likely as a result of domestication and the start of selective breeding programmes for these species in Europe. Conclusions Our findings highlight the need to broaden the genetic composition of the base populations from which selection programmes start, and suggest that measures designed to increase effective population size within all farmed populations analysed here should be implemented in order to manage genetic variability and ensure the sustainability of the breeding programmes.

Abstract Background Genomic relationship matrices are used to obtain genomic inbreeding coefficients. However, there are several methodologies to compute these matrices and there is still an unresolved debate on which one provides the best estimate of inbreeding. In this study, we investigated measures of inbreeding obtained from five genomic matrices, including the Nejati-Javaremi allelic relationship matrix (F NEJ ), the Li and Horvitz matrix based on excess of homozygosity (F L&H ), and the VanRaden (methods 1, F VR1, and 2, F VR2) and Yang (F YAN ) genomic relationship matrices. We derived expectations for each inbreeding coefficient, assuming a single locus model, and used these expectations to explain the patterns of the coefficients that were computed from thousands of single nucleotide polymorphism genotypes in a population of Iberian pigs. Results Except for F NEJ , the evaluated measures of inbreeding do not match with the original definitions of inbreeding coefficient of Wright (correlation) or Malécot (probability). When inbreeding coefficients are interpreted as indicators of variability (heterozygosity) that was gained or lost relative to a base population, both F NEJ and F L&H led to sensible results but this was not the case for F VR1, F VR2 and F YAN . When variability has increased relative to the base, F VR1, F VR2 and F YAN can indicate that it decreased. In fact, based on F YAN , variability is not expected to increase. When variability has decreased, F VR1 and F VR2 can indicate that it has increased. Finally, these three coefficients can indicate that more variability than that present in the base population can be lost, which is also unreasonable. The patterns for these coefficients observed in the pig population were very different, following the derived expectations. As a consequence, the rate of inbreeding depression estimated based on these inbreeding coefficients differed not only in magnitude but also in sign. Conclusions Genomic inbreeding coefficients obtained from the diagonal elements of genomic matrices can lead to inconsistent results in terms of gain and loss of genetic variability and inbreeding depression estimates, and thus to misleading interpretations. Although these matrices have proven to be very efficient in increasing the accuracy of genomic predictions, they do not always provide a useful measure of inbreeding.

El paradigma histórico-cultural y la teoría de la actividad representan un modelo teórico-metodológico para realizar investigación educativa. Este enfoque ofrece una visión dialéctica y dinámica sobre el proceso del desarrollo del niño y el rol de la educación en sus diversos niveles. El método fundamental de investigación de este enfoque es el experimento formativo, que fue denominado como genético-experimental por el propio Vigotsky, así como la evaluación educativa que se puede realizar desde el análisis estructural de la actividad. En este artículo se analizan los avances obtenidos en las investigaciones educativas aplicadas a los participantes de edad preescolar, la edad escolar y adultos. Las investigaciones se realizaron como proyectos de tesis doctorales, sus resultados se presentaron en ponencias, artículos y capítulos en libros. Se discuten las aportaciones originales desde este modelo teórico-metodológico.