Los híbridos y las quimeras humanos de nuevo a debate / Hybrids and human chimeras again in debate

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Persistence of sunflower crop traits and fitness in Helianthus petiolaris populations.

Transgenic plants have increased interest in the study of crop gene introgression in wild populations. Genes (or transgenes) conferring adaptive advantages persist in introgressed populations, enhancing competitiveness of wild or weedy plants. This represents an ecological risk that could increase problems of weed control. Introgression of cultivar alleles into wild plant populations via crop-wild hybridisations is primarily governed by their fitness effect. To evaluate this, we studied the second generation of seven wild-crop interspecific hybrids between weedy Helianthus petiolaris and cultivated sunflower, H. annuus var. macrocarpus. The second generation comprised open-pollinated progeny and backcrosses to the wild parent, mimicking crosses that occur in natural situations. We compared a number of morphological, life history and fitness traits. Multivariate analysis showed that the parental species H. annuus and H. petiolaris differed in a number of morphological traits, while the second hybrid generation between them was intermediate. Sunflower crop introgression lowered fitness of interspecific hybrids, but fitness parameters tended to recover in the following generation. Relative frequency of wild/weedy and introgressed plants was estimated through four generations, based on male and female parent fitness. In spite of several negative selection coefficients observed in the second generation, introgressed plants could be detected in stands of <100 weedy H. petiolaris populations. The rapid recovery of fecundity parameters leads to prediction that any trait conferring an ecological advantage will diffuse into the wild or weedy population, even if F1 hybrids have low fitness.

La biotipología en el pronatalismo argentino (1930-1983) / No disponible

El objetivo central del presente trabajo consiste en revisar las propuestas pronatalistas argentinas del período 1930-1983 y evaluar las influencias que recibieran de la Biotipología de Nicola Pende. Esta disciplina, derivada de la Eugenesia de Francis Galton y funcional a regímenes autoritarios, tuvo gran aceptación en la ortodoxia eugénica de la Italia de Mussolini, la España de Franco y la Argentina de aquellos años. En torno a ella se articuló un discurso demográfico de claro sesgo tomista en el cual el fomento de la "natalidad seleccionada" fue, como veremos, uno de sus aspectos más destacados

The goal of this paper consists in the revision of argentinean pronatalist ideas of the period 190-1983 and so doing, in the evaluating the influences that they received from Nicola Pende´s Biotypology. This subject, derived from Francis Galton´s Eugenics, was usefull to autoritarian systems so it was very well accepted for the eugenic orthodoxic of Mussolini´s Italy, Franco´s Spain and the Argentina of those years. Around it, politics and demographers articulated a thomist speech with prominent emphasis in the promotion of a "selected natality"

Crossing species boundaries.

This paper critically examines the biology of species identity and the morality of crossing species boundaries in the context of emerging research that involves combining human and nonhuman animals at the genetic or cellular level. We begin with the notion of species identity, particularly focusing on the ostensible fixity of species boundaries, and we explore the general biological and philosophical problem of defining species. Against this backdrop, we survey and criticize earlier attempts to forbid crossing species boundaries in the creation of novel beings. We do not attempt to establish the immorality of crossing species boundaries, but we conclude with some thoughts about such crossings, alluding to the notion of moral confusion regarding social and ethical obligations to novel interspecies beings.