A framework for the integration of development and evolution: The forgotten legacy of James Meadows Rendel.

The historical challenges to bridge the gaps between developmental biology and population or statistical genetics under the explanatory dominance of the Modern Evolutionary Synthesis during the 20th century have been thoroughly documented. However, although several attempts to integrate these fields have been made, most have been deemed unsuccessful. As an example of those efforts, in this paper I discuss the work of James Meadows Rendel, a student of J. B. S. Haldane and disciple of Conrad Hal Waddington. I present his largely forgotten or unrecognized, but innovative, ideas about canalization and the role of development in phylogeny as a valuable piece to connect these fields that could still have important ramifications for today's evolutionary biology. In fact, it is expected that the legacy of J. M. Rendel will be rediscovered, and more importantly, incorporated and extended by future researchers, in light of the growth of evolutionary developmental biology in the last decades. What is more, this case offers a chance to critically revisit standard historiographies about the dichotomy between developmental and population genetics research frameworks in 20th century biology.

Stage- and thermal-specific genetic architecture for preadult viability in natural populations of Drosophila melanogaster.

Studying the processes affecting variation for preadult viability is essential to understand the evolutionary trajectories followed by natural populations. This task requires focusing on the complex nature of the phenotype-genotype relationship by taking into account usually neglected aspects of the phenotype and recognizing the modularity between different ontogenetic stages. Here, we describe phenotypic variability for viability during the larval and pupal stages in lines derived from three natural populations of Drosophila melanogaster, as well as the variability for phenotypic plasticity and canalization at two different rearing temperatures. The results indicate that the three populations present significant phenotypic differences for preadult viability. Furthermore, distinct aspects of the phenotype (means, plasticity, canalization, plasticity of canalization) are affected by different genetic bases underlying changes in viability in a stage- and environment-specific manner. These findings explain the generalized maintenance of genetic variability for this fitness trait.

From collective health to "personalized" medicine: bioethical challenges in preimplantation genetic testing from a North-South perspective. / De la salud colectiva a la medicina "personalizada": desafíos bioéticos de la evaluación genética preimplantatoria desde la perspectiva norte-sur.

This article examines the scope and limitations of the precision medicine paradigm and its relationship with the collective health approach. To that end, it takes preimplantation genetic testing (PGT) as a paradigmatic example of technologies aimed at the "individualization" of health processes. In this regard, we review the characteristics and scientific and regulatory foundations of PGT technologies in Argentina, and discuss the next steps for their bioethical analysis. More specifically, we shed light on some of the conditions for their implementation from a north-south perspective. We propose three themes or problematic aspects as a synthesis of our analysis, related to biases in the production of knowledge, the values and interests underlying its uses, and the underlying epistemological assumptions of these technologies. Throughout the article, we review these dilemmas and suggest some issues that should be taken into account in future research.

El artículo se interroga por los alcances y los límites del paradigma de la medicina de precisión y su relación con el enfoque de la salud colectiva. Para ello, se toma la evaluación genética preimplantatoria o PGT (preimplantation genetic testing) dado que constituye un ejemplo paradigmático de tecnologías que apuntan a la "individualización" de los procesos de salud. En esta dirección, se revisan las características y los fundamentos científico-normativos acerca de las tecnologías PGT en Argentina, y el camino que queda por recorrer para su análisis bioético. De manera más específica, se visibilizan algunas de las condiciones de posibilidad para su implementación desde la perspectiva norte-sur. Como síntesis del análisis, proponemos tres ejes o nudos problemáticos relacionados con los sesgos en la producción de conocimiento, los valores e intereses subyacentes a sus usos y los presupuestos epistemológicos que operan en la base de estas tecnologías. A lo largo de este trabajo, presentamos estos dilemas y sugerimos algunas recomendaciones para ser tenidas en cuenta en futuras investigaciones.

Phenotypic decanalization driven by social determinants could explain variance patterns for glycemia in adult urban Argentinian population.

Type 2 diabetes, one of the major causes of death and disability worldwide, is characterized by problems in the homeostasis of blood glucose. Current preventive policies focus mainly on individual behaviors (diet, exercise, salt and alcohol consumption). Recent hypotheses state that the higher incidence of metabolic disease in some human populations may be related to phenotypic decanalization causing a heightened phenotypic variance in response to unusual or stressful environmental conditions, although the nature of these conditions is under debate. Our aim was to explore variability patterns of fasting blood glucose to test phenotypic decanalization as a possible explanation of heightened prevalence for type 2 diabetes in some groups and to detect variables associated with its variance using a nation-wide survey of Argentinian adult population. We found patterns of higher local variance for fasting glycemia associated with lower income and educational attainment. We detected no meaningful association of glycemia or its variability with covariates related to individual behaviors (diet, physical activity, salt or alcohol consumption). Our results were consistent with the decanalization hypothesis for fasting glycemia, which appears associated to socioeconomic disadvantage. We therefore propose changes in public policy and discuss the implications for data gathering and further analyses.