Human capital distribution, growth and convergence

This paper studies the dynamic relationship between distribution and endogenous growth in an overlapping generations model with accumulation of human and physical capital. It is shown how human capital can determine a relationship between per capita growth rates and inequality in the distribution of income. Family background effects and spillovers in the transmission of human capital generate a dynamics in which aggregate variables depend not only on the stock, but also on the distribution of human capital. The evolution of this distribution over time is then characterized under different assumptions on private returns and the form of the externality in the technology for humancapital. Conditions for existence, uniqueness and stability of a constant growth equilibrium with a stationary distribution are derived. Increasing returns, idiosyncratic abilities and the possibility of poverty traps are explicitely characterized in a closed form solution of the equilibrium dynamics, showing the role played by technology and preferences parameters.

RPS4Y gene family evolution in primates

Background: The RPS4 gene codifies for ribosomal protein S4, a very well-conserved protein present in all kingdoms. In primates, RPS4 is codified by two functional genes located on both sex chromosomes: the RPS4X and RPS4Y genes. In humans, RPS4Y is duplicated and the Y chromosome therefore carries a third functional paralog: RPS4Y2, which presents a testis-specific expression pattern. Results: DNA sequence analysis of the intronic and cDNA regions of RPS4Y genes from species covering the entire primate phylogeny showed that the duplication event leading to the second Y-linked copy occurred after the divergence of New World monkeys, about 35 million years ago. Maximum likelihood analyses of the synonymous and non-synonymous substitutions revealed that positive selection was acting on RPS4Y2 gene in the human lineage, which represents the first evidence of positive selection on a ribosomal protein gene. Putative positive amino acid replacements affected the three domains of the protein: one of these changes is located in the KOW protein domain and affects the unique invariable position of this motif, and might thus have a dramatic effect on the protein function.Conclusion: Here, we shed new light on the evolutionary history of RPS4Y gene family, especially on that of RPS4Y2. The results point that the RPS4Y1 gene might be maintained to compensate gene dosage between sexes, while RPS4Y2 might have acquired a new function, at least in the lineage leading to humans.

ORMDL proteins are a conserved new family of endoplasmic reticulum membrane proteins

Background: Annotations of completely sequenced genomes reveal that nearly half of the genes identified are of unknown function, and that some belong to uncharacterized gene families. To help resolve such issues, information can be obtained from the comparative analysis of homologous genes in model organisms. Results: While characterizing genes from the retinitis pigmentosa locus RP26 at 2q31-q33, we have identified a new gene, ORMDL1, that belongs to a novel gene family comprising three genes in humans (ORMDL1, ORMDL2 and ORMDL3), and homologs in yeast, microsporidia, plants, Drosophila, urochordates and vertebrates. The human genes are expressed ubiquitously in adult and fetal tissues. The Drosophila ORMDL homolog is also expressed throughout embryonic and larval stages, particularly in ectodermally derived tissues. The ORMDL genes encode transmembrane proteins anchored in the endoplasmic reticulum (ER). Double knockout of the two Saccharomyces cerevisiae homologs leads to decreased growth rate and greater sensitivity to tunicamycin and dithiothreitol. Yeast mutants can be rescued by human ORMDL homologs. Conclusions: From protein sequence comparisons we have defined a novel gene family, not previously recognized because of the absence of a characterized functional signature. The sequence conservation of this family from yeast to vertebrates, the maintenance of duplicate copies in different lineages, the ubiquitous pattern of expression in human and Drosophila, the partial functional redundancy of the yeast homologs and phenotypic rescue by the human homologs, strongly support functional conservation. Subcellular localization and the response of yeast mutants to specific agents point to the involvement of ORMDL in protein folding in the ER.

Shaping mechanisms of metal specificity in a family of metazoan Metallothioneins: evolutionary differentiation of Mollusc MTs.

Background: The degree of metal binding specificity in metalloproteins such as metallothioneins (MTs) can be crucial for their functional accuracy. Unlike most other animal species, pulmonate molluscs possess homometallic MT isoforms loaded with Cu+ or Cd2+. They have, so far, been obtained as native metal-MT complexes from snail tissues, where they are involved in the metabolism of the metal ion species bound to the respective isoform. However, it has not as yet been discerned if their specific metal occupation is the result of a rigid control of metal availability, or isoform expression programming in the hosting tissues or of structural differences of the respective peptides determining the coordinative options for the different metal ions. In this study, the Roman snail (Helix pomatia) Cu-loaded and Cd-loaded isoforms (HpCuMT and HpCdMT) were used as model molecules in order t o elucidate the biochemical and evolutionary mechanisms permitting pulmonate MTs to achieve specificity for their cognate metal ion. Results: HpCuMT and HpCdMT were recombinantly synthesized in the presence of Cd2+, Zn2+ or Cu2+ and corresponding metal complexes analysed by electrospray mass spectrometry and circular dichroism (CD) and ultra violet-visible (UV-Vis) spectrophotometry. Both MT isoforms were only able to form unique, homometallic and stable complexes (Cd6-HpCdMT and Cu12-HpCuMT) with their cognate metal ions. Yeast complementation assays demonstrated that the two isoforms assumed metal-specific functions, in agreement with their binding preferences, in heterologous eukaryotic environments. In the snail organism, the functional metal specificity of HpCdMT and HpCuMT was contributed by metal-specific transcription programming and cell-specific expression. Sequence elucidation and phylogenetic analysis of MT isoforms from a number of snail species revealed that they possess an unspecific and two metal-specific MT isoforms, whose metal specificity was achieved exclusively by evolutionary modulation of non-cysteine amino acid positions. Conclusion: The Roman snail HpCdMT and HpCuMT isoforms can thus be regarded as prototypes of isoform families that evolved genuine metal-specificity within pulmonate molluscs. Diversification into these isoforms may have been initiated by gene duplication, followed by speciation and selection towards opposite needs for protecting copper-dominated metabolic pathways from nonessential cadmium. The mechanisms enabling these proteins to be metal-specific could also be relevant for other metalloproteins.

Comparative genomic analysis of the odorant-binding protein family in 12 Drosophila genomes: purifying selection and birth-and-death evolution

Background: Chemoreception is a widespread mechanism that is involved in critical biologic processes, including individual and social behavior. The insect peripheral olfactory system comprises three major multigene families: the olfactory receptor (Or), the gustatory receptor (Gr), and the odorant-binding protein (OBP) families. Members of the latter family establish the first contact with the odorants, and thus constitute the first step in the chemosensory transduction pathway.Results: Comparative analysis of the OBP family in 12 Drosophila genomes allowed the identification of 595 genes that encode putative functional and nonfunctional members in extant species, with 43 gene gains and 28 gene losses (15 deletions and 13 pseudogenization events). The evolution of this family shows tandem gene duplication events, progressive divergence in DNA and amino acid sequence, and prevalence of pseudogenization events in external branches of the phylogenetic tree. We observed that the OBP arrangement in clusters is maintained across the Drosophila species and that purifying selection governs the evolution of the family; nevertheless, OBP genes differ in their functional constraints levels. Finally, we detect that the OBP repertoire evolves more rapidly in the specialist lineages of the Drosophila melanogaster group (D. sechellia and D. erecta) than in their closest generalists.Conclusion: Overall, the evolution of the OBP multigene family is consistent with the birth-and-death model. We also found that members of this family exhibit different functional constraints, which is indicative of some functional divergence, and that they might be involved in some of the specialization processes that occurred through the diversification of the Drosophila genus.

The profile of general practitioners (GPs) who publish in selected family practice journals

Background: Providing support for research is one of the key issues in the ongoing attempts to improve Primary Care. However, when patient care takes up a significant part of a GP's time, conducting research is difficult. In this study we examine the working conditions and profile of GPs who publish in three leading medical journals and propose possible remedial policy actions. Findings: The authors of all articles published in 2006 and 2007 in three international Family Medicine journals - Annals of Family Medicine, Family Practice, and Journal of Family Practice - were contacted by E-mail. They were asked to complete a questionnaire investigating the following variables: availability of specific time for research, time devoted to research, number of patients attended, and university affiliation. Only GPs were included in the study. Three hundred and ten relevant articles published between 2006 and 2007 were identified and the authors contacted using a survey tool. 124 researchers responded to our questionnaire; 45% of respondents who were not GPs were excluded. On average GPs spent 2.52 days per week and 6.9 hours per day on patient care, seeing 45 patients per week. Seventy-five per cent of GPs had specific time assigned to research, on average 13 hours per week; 79% were affiliated to a university and 69% held teaching positions. Conclusions: Most GPs who publish original articles in leading journals have time specifically assigned to research as part of their normal working schedule. They see a relatively small number of patients. Improving the working conditions of family physicians who intend to investigate is likely to lead to better research results.

ORMDL proteins are a conserved new family of endoplasmic reticulum membrane proteins

Background: Annotations of completely sequenced genomes reveal that nearly half of the genes identified are of unknown function, and that some belong to uncharacterized gene families. To help resolve such issues, information can be obtained from the comparative analysis of homologous genes in model organisms. Results: While characterizing genes from the retinitis pigmentosa locus RP26 at 2q31-q33, we have identified a new gene, ORMDL1, that belongs to a novel gene family comprising three genes in humans (ORMDL1, ORMDL2 and ORMDL3), and homologs in yeast, microsporidia, plants, Drosophila, urochordates and vertebrates. The human genes are expressed ubiquitously in adult and fetal tissues. The Drosophila ORMDL homolog is also expressed throughout embryonic and larval stages, particularly in ectodermally derived tissues. The ORMDL genes encode transmembrane proteins anchored in the endoplasmic reticulum (ER). Double knockout of the two Saccharomyces cerevisiae homologs leads to decreased growth rate and greater sensitivity to tunicamycin and dithiothreitol. Yeast mutants can be rescued by human ORMDL homologs. Conclusions: From protein sequence comparisons we have defined a novel gene family, not previously recognized because of the absence of a characterized functional signature. The sequence conservation of this family from yeast to vertebrates, the maintenance of duplicate copies in different lineages, the ubiquitous pattern of expression in human and Drosophila, the partial functional redundancy of the yeast homologs and phenotypic rescue by the human homologs, strongly support functional conservation. Subcellular localization and the response of yeast mutants to specific agents point to the involvement of ORMDL in protein folding in the ER.

The biological family from the perspective of kinship fostered adolescents

Background: Previous studies emphasise the importance of the biological family to the welfare of fostered adolescents. However, the majority of these studies only take into consideration the viewpoints of the professionals, foster parents and biological parents not those of the adolescents themselves. For this reason little is known about the perceptions the adolescents have and the needs they express. Method: This study has gathered data from 57 adolescents in kinship family fostering in Spain (AFE). The study applied qualitative reseach, using focus groups to gather data and the Atlas.ti programme to analyse the data. The qualitative data give us a more profound understanding of how the fostered adolescents relate to their biological families. Results: The results highlight the specific needs of these adolescents a) an understanding of their family history b) the impact of visits from and relationship with their biological family and c) the relationship between the biological family and the foster family. Conclusions: These findings reveal implications to consider when creating support programmes aimed at this group.

An Atkinson-Gini family of social evaluation functions

We investigate the properties of a family of social evaluation functions and inequality indices which merge the features of the family of Atkinson (1970) and S-Gini (Donaldson and Weymark (1980, 1983), Yitzhaki (1983) and Kakwani (1980)) indices. Income inequality aversion is captured by decreasing marginal utilities, and aversion to rank inequality is captured by rank-dependent ethical weights, thus providing an ethically-flexible dual basis for the assessment of inequality and equity. These ocial evaluation functions can be interpreted as average utility corrected for the illfare of relative deprivation. They can alternatively be understood as averages of altruistic well-being in a population. They moreover have a simple graphical interpretation.

Parental education and family characteristics: educational opportunities across cohorts in Italy and Spain

Drawing on data contained in the 2005 EU-SILC, this paper investigates the disparities in educational opportunities in Italy and Spain. Its main objective is to analyse the predicted probabilities of successfully completing upper-secondary and tertiary education for individuals with different parental backgrounds, and the changes in these probabilities across birth cohorts extending from 1940 to 1980. The results suggest that the disparities in tertiary education opportunities in Italy tend to increase over time. By contrast, the gap in educational opportunity in Spain shows a marked decrease across the cohorts. Moreover, by using an intuitive decomposition strategy, the paper shows that a large part of the educational gap between individuals of different backgrounds is “composed” of the difference in the endowment of family characteristics. Specifically, it seems that more highly educated parents are more able to endow their children with a better composition of family characteristics, which accounts for a significant proportion of the disparities in educational opportunity.

Desarrollo de una colección de Líneas Casi Isogénicas (NIL) para el estudio de caracteres de interés agronómico en especies del género Fragaria

Fragaria vesca posee varias características que la hacen interesante como especie modelo en la familia Rosaceae. Además, su naturaleza diploide permite sortear la complejidad genética de la fresa cultivada. Considerando que los genomas de las especies diploides y octoploides de Fragaria mantienen una relación de sintenia y colinearidad, estamos desarrollando una colección de Líneas Casi Isogénicas (NIL) en Fragaria diploide, usando Fragaria bucharica, una variedad asiática, como donante de introgresiones y Fragaria vesca var. Reine des Vallées, una variedad francesa comúnmente cultivada en España para usos industriales, como parental recurrente. Para obtener introgresiones de F. bucharica en un fondo genético homogéneo de F. vesca, se desarrolló un retrocruzamiento y se obtuvo una población BC1 que fue analizada para la presencia de alelos de F. bucharica a lo largo de los 7 grupos de ligamiento (LG) del mapa de referencia de Fragaria. Los individuos con bajo número de introgresiones de gran tamaño, que en conjunto abarcaron todo el genoma de F. bucharica, fueron seleccionados y retrocruzados con el parental recurrente. La descendencia fue analizada para los loci segregantes y los individuos BC2 con 1 ó 2 introgresiones fueron seleccionados como líneas donadoras de introgresiones de las NIL. Hasta el momento se han descrito tres fenotipos dominantes diferentes bajo condiciones de invernadero en varias NIL heterozigóticas: Las plantas con introgresiones en LG2 presentan estolones. Las plantas con introgresiones en LG1 y LG3 presentan floración temprana. Las plantas con introgresiones en LG6 presentan floración estacional. Actualmente se está trabajando en la selección y caracterización de introgresiones de pequeño tamaño mediante la autofecundación de las líneas seleccionadas. La caracterización fenotípica de los recombinantes seleccionados permitirá localizar y estimar los patrones de herencia de los genes implicados en los caracteres descritos, además de la identificación de nuevos caracteres recesivos que aparecerán en homozigosis.

Telomere characterization in the Asteraceae family

Asteraceae or Compositae constitute one of the largest families of the angiosperms, distributed over all continents but in Antarctica, particularly well represented in temperate zones and less frequent in tropical regions. The Asteraceae have been the object of a great deal of attention from all viewpoints for their scientific as well as economic interest. Telomeres sequences are highly conservated at the ends of chromosomes across the eukaryotes. In plants, generally are formed by tandemly repeated sequences named Arabidopsis type but several exceptions have been described. The objective of the present work is to study the telomeric characterization along the whole Asteraceae family and to find, if any, the relationships between these results and the evolutionary history in this family.

Family-based affirmative action? Subversion and resilience strategies of gay father families

The present doctoral dissertation is aimed at analyzing how and with what consequences gay father families and their children’s schools negotiate possible differences in the construction of family and gender at home and in the families’ social milieus. This objective fits in with the broader goal of researching how family-school interactons are influenced by the social context such as hegemonic masculinity (Connell, 2002). The thesis is based on qualitative fieldwork carried out with 18 nonheterosexual parent families in Spain, comprising 30 interviews with 44 people. The principal participant group were 14 de novo (adoptive and surrogacy) gay father families with resident preadolescent children. The findings revealed that all the de novo families assumed open communication strategies at school with inclusive consequences: apart from incidental questions and reactions of surprise, the children did not suffer homophobic bullying. The analisis showed that the necessary condition for inclusion was not the open communication but rather illocutionary orientation (Habermas, 1984; Soler & Flecha, 2010), understood as the parents’ sensitivity to the attitudes of their children and schools. The schools received the families in an inclusive manner, which, however, was only receptive and not proactive, therefore some of the families (reconstituted ones), coerced by the social context, got excluded. Gender relations at home were predominantly androgynous, and outside home predominantly traditional, yet the children negotiated this difference with inclusive consequences. They participated in hegemonic collective practices, thus confirming the thesis on the similarity between homo- and heterosexual-parent families (Golombok, 2006). Consistently, also the families’ identity politics was “assimilationist” and non-queer. Admittedly, the analisis showed that such a politics was increased by social expectations. Still, the findings suggest that educational and other family policies should draw on broad agendas of gender and family diversity rather than on the politics of difference and the unique status of LGB families.