Different Cranial Ontogeny in Europeans and Southern Africans

Modern human populations differ in developmental processes and in several phenotypic traits. However, the link between ontogenetic variation and human diversification has not been frequently addressed. Here, we analysed craniofacial ontogenies by means of geometric-morphometrics of Europeans and Southern Africans, according to dental and chronological ages. Results suggest that different adult cranial morphologies between Southern Africans and Europeans arise by a combination of processes that involve traits modified during the prenatal life and others that diverge during early postnatal ontogeny. Main craniofacial changes indicate that Europeans differ from Southern Africans by increasing facial developmental rates and extending the attainment of adult size and shape. Since other studies have suggested that native subsaharan populations attain adulthood earlier than Europeans, it is probable that facial ontogeny is linked with other developmental mechanisms that control the timing of maturation in other variables. Southern Africans appear as retaining young features in adulthood. Facial ontogeny in Europeans produces taller and narrower noses, which seems as an adaptation to colder environments. The lack of these morphological traits in Neanderthals, who lived in cold environments, seems a paradox, but it is probably the consequence of a warm-adapted faces together with precocious maturation. When modern Homo sapiens migrated into Asia and Europe, colder environments might establish pressures that constrained facial growth and development in order to depart from the warm-adapted morphology. Our results provide some answers about how cranial growth and development occur in two human populations and when developmental shifts take place providing a better adaptation to environmental constraints

Diversity among African Pygmies

Although dissimilarities in cranial and post-cranial morphology among African pygmies groups have been recognized, comparative studies on skull morphology usually pull all pygmies together assuming that morphological characters are similar among them and different with respect to other populations. The main aim of this study is to compare cranial morphology between African pygmies and non-pygmies populations from Equatorial Africa derived from both the Eastern and the Western regions in order to test if the greatest morphological difference is obtained in the comparison between pygmies and non-pygmies. Thirty three-dimensional (3D) landmarks registered with Microscribe in four cranial samples (Western and Eastern pygmies and non-pygmies) were obtained. Multivariate analysis (generalized Procrustes analysis, Mahalanobis distances, multivariate regression) and complementary dimensions of size were evaluated with ANOVA and post hoc LSD. Results suggest that important cranial shape differentiation does occur between pygmies and non-pygmies but also between Eastern and Western populations and that size changes and allometries do not affect similarly Eastern and Western pygmies. Therefore, our findings raise serious doubt about the fact to consider African pygmies as a homogenous group in studies on skull morphology. Differences in cranial morphology among pygmies would suggest differentiation after divergence. Although not directly related to skull differentiation, the diversity among pygmies would probably suggest that the process responsible for reduced stature occurred after the split of the ancestors of modern Eastern and Western pygmies

Los cuerpos indígenas entre textos y silencios. El caso de una niña Aché

The organization of collections of human remains of different “races”, during the end of the XIX century and the beginning of the XX century, was associated with archival work that enabled to certificate the authenticity of the specimens. These files contain individual data, such as the origin, sex, age and name, but also data about the collector or donor. This study analyses the different material and textual strategies carried out on a young Aché indigenous woman by the German anthropologist Robert Lehmann-Nitsche (1872-1938), responsible of the Sección Antropológica of the Museo de La Plata (Argentina); strategies through which the anthropologist built the epistemological value of the indigenous body and his own scientific authority. We also discuss how certain practices were inspired in written and non-written instructions, but sometimes personal motivations interrupted procedures for elaborate scientific objects, leaving “silences” that can only recently be interpreted in light of the claims existing over museums that house human remains.La formación de colecciones de restos humanos de distintas “razas”, hacia fines del siglo XIX y comienzos del XX, se asoció con la elaboración de un corpus documental que permitiese acreditar la autenticidad de los especímenes. En estos archivos constan datos individuales, como la procedencia, sexo, edad y el nombre, pero también sobre el colector o donante. A partir de las prácticas materiales y textuales efectuadas sobre una joven indígena Aché por el antropólogo alemán Robert Lehmann-Nitsche (1872-1938), jefe de la Sección Antropológica del Museo de La Plata (Argentina), este trabajo analiza las distintas estrategias para otorgar valor epistemológico al cuerpo indígena y la autoridad científica del propio investigador. Se discute además cómo algunas prácticas estuvieron inspiradas en instrucciones escritas o no escritas, pero a veces las motivaciones personales condujeron a interrumpir los procedimientos de producción de objetos de estudio, dejando “silencios” que solo recientemente pueden ser interpretados a la luz de los cuestionamientos que existen sobre los museos que albergan restos humanos

Insulin-like growth factor 2 (IGF2) protects against Huntington's disease through the extracellular disposal of protein aggregates

Impaired neuronal proteostasis is a salient feature of many neurodegenerative diseases, highlighting alterations in the function of the endoplasmic reticulum (ER). We previously reported that targeting the transcription factor XBP1, a key mediator of the ER stress response, delays disease progression and reduces protein aggregation in various models of neurodegeneration. To identify disease modifier genes that may explain the neuroprotective effects of XBP1 deficiency, we performed gene expression profiling of brain cortex and striatum of these animals and uncovered insulin-like growth factor 2 (Igf2) as the major upregulated gene. Here, we studied the impact of IGF2 signaling on protein aggregation in models of Huntington's disease (HD) as proof of concept. Cell culture studies revealed that IGF2 treatment decreases the load of intracellular aggregates of mutant huntingtin and a polyglutamine peptide. These results were validated using induced pluripotent stem cells (iPSC)-derived medium spiny neurons from HD patients and spinocerebellar ataxia cases. The reduction in the levels of mutant huntingtin was associated with a decrease in the half-life of the intracellular protein. The decrease in the levels of abnormal protein aggregation triggered by IGF2 was independent of the activity of autophagy and the proteasome pathways, the two main routes for mutant huntingtin clearance. Conversely, IGF2 signaling enhanced the secretion of soluble mutant huntingtin species through exosomes and microvesicles involving changes in actin dynamics. Administration of IGF2 into the brain of HD mice using gene therapy led to a significant decrease in the levels of mutant huntingtin in three different animal models. Moreover, analysis of human postmortem brain tissue and blood samples from HD patients showed a reduction in IGF2 level. This study identifies IGF2 as a relevant factor deregulated in HD, operating as a disease modifier that buffers the accumulation of abnormal protein species

Héctor Mario Pucciarelli, 1939-2018

ObituarioObituar

Influencia de la deformación artificial indeterminada en las comparaciones craneanas interpoblacionales

Consultar dentro del archivo del trabajo

Influencia de la deformación artificial indeterminada en las comparaciones craneanas interpoblacionales

Consultar dentro del archivo del trabajo

Influencia de la deformación artificial indeterminada en las comparaciones craneanas interpoblacionales

Consultar dentro del archivo del trabajo

Debates y decisiones políticas en torno de la exhibición de restos humanos en el Museo de La Plata / Debates and political decisions on the exhibition of human remains in the Museum of La Plata

Desde hace algunas décadas, el Museo de La Plata (Universidad Nacional de La Plata, Argentina) ha recibido reclamos por parte de comunidades aborígenes que solicitan la restitución de restos humanos, así como su retiro de las salas de exhibición. Conjuntamente con la aparición de normativas que reconocen derechos en los pueblos originarios y el debate de la propia comunidad académica, se ha desarrollado en los últimos años una política integral en relación con el manejo de restos humanos dentro de la institución. El objetivo de este trabajo es presentar los acontecimientos, debates y decisiones acerca de la modalidad de exhibición de restos humanos en el Museo de La Plata. El principal cambio se produjo en 2006, cuando se decidió retirar de exhibición las momias y partes esqueletarias de poblaciones aborígenes de América y, paralelamente, la elaboración de mensajes a los visitantes según estas decisiones políticas. El nuevo guión de la exposición gira en torno a la evolución humana, contemplando la inclusión de un sector especialmente dedicado a la reflexión sobre el significado de prácticas y representaciones sobre la muerte y los muertos, el valor del estudio científico sobre este tipo de evidencias y los derechos de las comunidades sobre sus muertos. Palabras clave: política; comunidades aborígenes; visitantes; museo Since some decades, aboriginal communities have been demanding to the Museo de La Plata that human remains be restored to the communities they belong to and removed from public exhibition. Regulations that recognize the rights of indigenous people, together with debates within the academic community, have contributed to the development of institutional policies on the treatment and care of human remains. The goal of this work is to present the events, debates and decisions related to the modes of exhibition of human remains in the Museum de La Plata. The main shift occurred in 2006 when it was decided that all mummies and skeletal parts belonging to American aborigines must be removed from exhibition. It was also considered necessary that the institution put up messages conveying these political decisions to visitors. The curation of the new exhibition is based on human evolution and includes a sector devoted to reflection on the meaning of the practices and representations about death and the dead, the scientific value of the study of human remains, and the rights of the communities to claim bodies. Keywords: policies; aboriginal communities; visitors; museu