The social groups that initially inhabited the hyper arid core of the Atacama Desert of northern Chile during the late Pleistocene integrated a wide range of local, regional and supra regional goods and ideas for their social reproduction as suggested by the archaeological evidence contained in several open camps in Pampa del Tamarugal (PdT). Local resources for maintaining their every-day life, included stone raw material, wood, plant and animal fibers, game, and fresh water acquired within a radius of ~30 km (ca. 1-2 days journey). At a regional scale, some goods were introduced from the Pacific coast (60-80 km to the west, ca. 3-4 days journey), including elongated rounded cobbles used as hammer stones in lithic production, and shells, especially from non-edible species of mollusks. From the Andes (ranging 80-150 km to the east, ca. 5-8 days of journey), they obtained camelid fiber, obsidian and a high-quality chalcedony, in addition to sharing knowledge on projectile point designs (Patapatane and Tuina type forms). Pieces of wood of a tropical forest tree species (Ceiba spp.) from the east Andean lowlands (600 km away, ca. 30 days of journey) were also brought to the PdT. While local goods were procured by the circulation of people within the PdT, the small number of foreign items would have been acquired through some sort of exchange networks that integrated dispersed local communities throughout several ecosystems. These networks may have been a key factor behind the success exhibited by these early hunter-gatherers in the hyper arid ecosystems of the Atacama Desert at the end of the Pleistocene. Different lines of archaeological evidence including open camps, workshop-quarries, lithic artifacts, archaeofaunal remains, plant and animal fibers and textiles, archaeobotanical remains, and paleoecological data show that people of the PdT managed a wide range of cultural items from the Pacific coast, the Andean highland and the tropical forest, that were integrated with resources gathered locally within the socio-cultural systems established by the end of the Pleistocene. These results are interpreted as material expressions of multi-scalar networking for resource management and other social material and immaterial requirements, which in other words, means that these people were actively connected to regional (coastal and highland), and supra-regional (trans-Andean) exchange networks from and out of the PdT.

Los grupos sociales que inicialmente habitaban el núcleo hiperárido del Desierto de Atacama en el norte de Chile durante el Pleistoceno tardío integraron una amplia gama de bienes e ideas, locales, regionales y supra regionales, para su reproducción social, como lo sugieren las evidencias arqueológicas materiales recuperadas en varios campamentos al aire libre en Pampa del Tamarugal (PdT). Los recursos locales para mantener su vida diaria, incluían materias primas líticas, fibras de plantas y animales, presas de caza y agua dulce adquiridos en un radio de -30 km (ca. 1-2 días de viaje). A escala regional, se introdujeron algunos elementos desde la costa del Pacífico (60-80 km hacia el oeste, ca. 3 a 4 días de viaje), incluidos rodados redondeados alargados, utilizados como percutores en la producción lítica y conchas, especialmente de especies no comestibles de moluscos. Desde los Andes (80-150 km al este, ca. 5-8 días de viaje), obtuvieron fibra de camélido, obsidiana y una calcedonia de alta calidad, además de compartir conocimientos sobre diseños de puntas de proyectil (tipo Patapatane y Tuina). También se llevaron a la PdT trozos de madera de una especie de árbol de los bosques tropicales (Ceiba spp.) de las tierras bajas al este de los Andes (600 km de distancia, ca. 30 días de viaje). Mientras que los bienes locales fueron adquiridos por la circulación de personas dentro de la PdT, el pequeño número de artículos foráneos se adquirieron a través de redes de intercambio que integraron comunidades locales dispersas en varios ecosistemas; lo que debió ser un factor clave detrás del éxito demostrado por estos primeros cazadores-recolectores en los ecosistemas hiperáridos del Desierto de Atacama hacia el final del Pleistoceno. Diferentes líneas de evidencia arqueológica que incluyen campamentos al aire libre, talleres, canteras, artefactos líticos, restos arqueofaunales, fibras y textiles de plantas y animales, restos arqueobotánicos y datos paleoecológicos, muestran que la gente de la PdT manejaron una amplia gama de elementos culturales desde la costa del Pacífico, el altiplano andino y el bosque tropical, que se integraron a los recursos recolectados localmente dentro de los sistemas socioculturales establecidos al final del Pleistoceno. Estos resultados se interpretan como una expresión material de una red de múltiples escalas para la gestión de recursos y otros requisitos sociales e inmateriales, lo que en otras palabras, significaría que estos grupos sociales estaban conectados activamente con redes de interacción regionales (costa y tierras altas) y supra-regionales (transandinas) desde y hacia la PdT.

In this work we test for the putative association between facial fluctuating asymmetry (FFA) and hormone treatments, maxillofacial surgery, orthodontics, injuries, and malformations. A protocol of five photographs and photogrammetric reconstruction was implemented to place thirty-four 3D landmarks in 3162 individuals aged between 18 and 85 years, belonging to the CANDELA initiative. A Procrustes ANOVA test was used to obtain individual facial fluctuating asymmetry scores. One way ANOVA, Welch, and Levene tests were conducted to explore the potential differences between mean and variance of the response variables. Our results indicate that women who received some hormonal treatment showed higher fluctuating facial asymmetry scores in relation to the unaffected group, this being persistent once the effects of heterozygosity (genetic ancestry) and further variables had been statistically controlled. The shape changes corresponding to this association are focused on the chin, jaw, lower lip, prefrontal region, nose, and ears. Previous reports suggested a potential relationship between facial asymmetry and hormone levels, but to the best of our knowledge there are no reports indicating the causation underlying the association detected here. This report is one more evidence of the association between hormone intake and facial asymmetric features in urban admixed Latin American populations. Rev Arg Antrop Biol 20(1), 2018. doi:10.17139/raab.2018.0020.01.06

En este trabajo se evalúa la relación entre la asimetría fluctuante facial (AFF) y los tratamientos hormonales, cirugías maxilofaciales, ortodoncia, traumatismos y malformaciones. En el marco del proyecto CANDELA, se tomaron cinco fotografías faciales de 3162 voluntarios entre los 18 y 85 años. Por fotogrametría se colocaron 34 landmarks o puntos en 3D y mediante el método Procrustes ANOVA se obtuvieron valores individuales de asimetría fluctuante facial. Se realizó una prueba de ANOVA de una vía y la prueba de Welch y Levene para conocer las diferencias entre media y varianza de los valores de asimetría facial y las variables respuesta. También, se caracterizó la variación morfológica del componente asimétrico de la forma facial mediante técnicas multivariadas sobre los grupos que resultaran diferentes significativamente. Las mujeres que reportaron haber recibido algún tipo de tratamiento hormonal mostraron mayores valores de asimetría fluctuante facial respecto al grupo sin tratamiento. Esta asociación se mantuvo una vez removido el efecto de la heterocigosidad (como indicador de la ancestría) y sin interactuar con el resto de covariables incluidas en el análisis. Los cambios morfológicos asociados a este factor se concentran en el mentón, maxilar labio inferior, región perifrontal, región nasal y orejas. Algunos trabajos anteriores dieron cuenta de la posible relación entre la asimetría facial y los niveles de hormonas, pero no hay estudios que sustenten la relación causal o directa entre la asociación aquí planteada. El presente trabajo es una evidencia más de la asociación entre el consumo de hormonas y modificaciones de caracteres faciales en poblaciones urbanas mestizas latinoamericanas. Rev Arg Antrop Biol 20(1), 2018. doi:10.17139/raab.2018.0020.01.06

Abstract: Despite efforts made by numerous researchers, existing knowledge about the origin of the majority of Chilean ethnic populations continues to be fragmentary and partially contradictory. Our aim is to contribute to the clarification of this important aspect of Chilean history, from the perspective of historical genetics. We first examine the variation of pan-American haplogroups of mitochondrial DNA (A, B, C and D) in five natural regions of continental Chile: Norte Grande (Far North), Norte Chico (Near North), Central Zone, Southern Zone and Southernmost Zone. When evaluating the distribution of men and women of American ancestral origin, the predominance of women over men is noticeable. In contrast, when the gender distribution of individuals of European ancestral origin is analyzed, male predominance is consistently observed. Next we calculated genetic distances between representatives of different ethnic groups of the southern cone of South America, the natural regions of Chile and mixed populations of Brazil, Bolivia, Peru and Argentina. As expected, genetic distances indicate proximity between Quechua, Aymara, and Atacameño and the Norte Grande, and between Pehuenche, Mapuche, Huilliche, Tehuelche, Alacalufe, Yagan and Ona and the Southern and Southernmost Zone. In addition, displacements of groups and population mixing involving the Amazon, Central Andes and Argentina are revealed, contributing to a clearer understanding of the geographical origin of Chilean ethnic groups.

Resumen: A pesar del esfuerzo realizado por numerosos investigadores, el conocimiento existente acerca del origen de la mayoría de los pue- blos originarios chilenos continúa siendo fragmentario y parcialmente contradictorio. En consecuencia nos hemos propuesto como objetivo contribuir al esclarecimiento de este importante aspecto de la historia del pueblo chileno, ofreciendo un enfoque desde la perspectiva de la genética histórica. Examinamos, en primer lugar, la variación que presentan los haplogrupos pan-americanos de ADN mitocondrial (A, B, C y D) de poblaciones actuales de cinco regiones naturales de Chile continental: Norte Grande, Norte Chico, Zona Central, Zona Sur y Zona Austral. Al evaluar la distribución de hombres y mujeres de origen ancestral americano se observa una predominancia de mujeres sobre hombres, contrastando este hecho con la distribución de géneros en el grupo de origen europeo, donde se observa consistentemente predominancia del sexo masculino. Luego calculamos distancias genéticas entre representantes de diferentes grupos originarios del cono sur, las regiones naturales de Chile y poblaciones mixtas de Brasil, Bolivia, Perú y Argentina. Las distancias genéticas obtenidas indican, como era de esperar, proximidad genética entre los pueblos quechua, aimara, y atacameño y el Norte Grande y entre pehuenches, mapuches, huilliches, tehuelches, alacalufes, yaganes y onas y la Zona Sur y Austral y sugieren desplazamientos y mezcla poblacional de grupos de la Amazonia, los Andes Centrales, Chile y Argentina, que tomados en conjunto, contribuyen a entender con mayor claridad el origen geográfico de los grupos étnicos chilenos.

This review aims to summarize information about the genetic etiology of attention deficit disorder with hyperactivity (ADHD), with particular reference to the contributions of our research group. We also discuss the genetic comorbidity estimated from genome-wide single nucleotide polymorphisms (SNP´s) between ADHD and major psychiatric disorders such as schizophrenia (E), major depressive disorder (MDD), bipolar disorder (BD) and autism spectrum disorders (ASD). A high genetic comorbidity was found between E and BD (46%), a moderate comorbidity between MDD and E, MDD and BD and MDD and ADHD (18%, 22% and 10% respectively) and a low comorbidity between E and ASD (2.5%). Furthermore, we show evidence concerning the genetic determination of psychiatric diseases, which is significantly lower when it is estimated from genome-wide SNP´s rather than using traditional quantitative genetic methodology (ADHD = E = 23%, BD = 25%, MDD = 21% and ASD = 17%). From an evolutionary perspective, we suggest that behavioral traits such as hyperactivity, inattention and impulsivity, which play a role in ADHD and perhaps also other hereditary traits which are part of major psychiatric disorders, could have had a high adaptive value during the early stages of the evolution of Homo sapiens. However, they became progressively less adaptive and definitively disadvantageous, to the extreme that they are involved in frequently diagnosed major psychiatric disorders.

Background: Amerindian admixture is an important parameter to consider in epidemiological studies in American countries, to make a proper selection of cases and controls. Aim: To compare Amerindian admixture estimates obtained using ABO*A and ABO*O blood group alleles and ancestral identity markers (AIMs) in the mixed Chilean population. Subjects and Methods: Amerindian admixture rates were determined in 720 Chilean volunteers residing in Arica and born in the 15 regions of the country, using ABO*O and ABO*A alleles and 40 AIMs selected from more than 500,000 single nucleotide polymorphisms (SNPs). Results: Mean admixture estimates obtained using ABO*O and ABO*A alleles and AIMs were 35, 47% and 48% respectively. There was concordance in estimates, with the exception of the admixture based on ABO*O allele and AIMs. Conclusions: In Chile, Amerindian admixture estimates obtained using ABO*A could be used as an alternative to AIMs in justified cases provided the sample size is reasonably large.

Background: Studies performed in Andean populations living in high altitude, indicate that the reduced availability of oxygen could be associated to both a fetal growth retardation and a lower birth weight. These variables are predictive of morbidity and mortality during the first year of life. Aim: To study perinatal variables of newborns of mothers living at contrasting altitudinal levels, harboring different degrees of Aymara ancestry. Subjects and Methods: Review of medical records of 5,295 women whose deliveries occurred between February 2004 and August 2010. Information was obtained on place of residence, grouped into two categories: coast (150 to 3,000 m) and high plateau (3,000 to 4,300 m), ancestry was estimated using number of Aymara surnames that were homologated to percentages of Amerindian admixture, gestational age, birth weight, height, head circumference and obstetric variables. Results: Gestational age showed a tendency to increase and birth weight, height and head circumference to decrease with altitude of residence. Only weight reached statistical significance. Women with Aymara ancestry gave birth to children with a significantly higher gestational age, weight and cranial circumference. Conclusions: Altitude of residence is related to a decrease in perinatal variables that proved to be less pronounced in newborns of mothers with a higher degree of Aymara ancestry. Results suggest a genetic adaptation to hypoxia that could be related to candidate genes linked to the capture, transport or utilization of oxygen.

Background: The geographical distribution of genes plays a key role in genetic epidemiology. The Chilean population has three major stem groups (Native American, European and African). Aim: To estimate the regional rate of American, European and African admixture of the Chilean population. Subjects and Methods: Forty single nucleotide polymorphisms (SNP´s) which exhibit substantially different frequencies between Amerindian populations (ancestry-informative markers or AIM´s), were genotyped in a sample of 923 Chilean participants to estimate individual genetic ancestry. Results: The American, European and African individual average admixture estimates for the 15 Chilean Regions were relatively homogeneous and not statistically different. However, higher American components were found in northern and southern Chile and higher European components were found in central Chile. A negative correlation between African admixture and latitude was observed. On the average, American and European genetic contributions were similar and significantly higher than the African contribution. Weighted mean American, European and African genetic contributions of 44.34% ± 3 9%, 51.85% ± 5.44% and 3.81% ± 0.45%, were estimated. Fifty two percent of subjects harbor African genes. Individuals with Aymara and Mapuche surnames have an American admixture of 58.64% and 68.33%, respectively. Conclusions: Half of the Chilean population harbors African genes. Participants with Aymara and Mapuche surnames had a higher American genetic contribution than the general Chilean population. These results confirm the usefulness of surnames as a frst approximation to determine genetic ancestry.

This essay discusses hypotheses about the biological origin and the embalming techniques developed by Archaic Chinchorro maritime hunter-gatherers. Recent publications on this subject are critically analyzed and used as a starting point to put forward related hypotheses. Based on recent evidence, it is not possible to claim that the Chinchorro are direct descendants of Early Archaic Acha fishermen and reject a priori that they underwent possible miscegenation with neighboring groups ca. 7,000 BP. On the other hand, there is not sufficient evidence available to postulate that the embalming technique developed by the Chinchorro has a highland and / or tropical forest origin. Models proposed to explain the onset of embalming do not accommodate the fact that only some bodies underwent this process. This casts doubt on the idea that the Chinchorro were an egalitarian society and precludes discussion of the possible existence of social strata. The special characteristics of the interventions on the dead bodies could have allowed family members to extend the social death of their deceased relatives, moving them to small coves where they established their temporary residence on the coast. It is likely that the discontinuation of the practice of embalming was related to the arrival in the coastal valleys of highland groups, which introduced different lifestyles, including the first agricultural practices. The fact that the embalming techniques denote the emergence of early artistic activities of ideological nature, not directly related to the struggle for survival, is one of the most outstanding cultural features of the Chinchorro.

Este ensayo tiene por objetivo analizar y comentar información relacionada con el origen biológico y las técnicas de embalsamamiento que emplearon los grupos arcaicos costeros del norte de Chile. Publicaciones recientes sobre el tema son analizadas críticamente y utilizadas como punto de partida para plantear hipótesis relacionadas. No es posible asegurar, con base en evidencia reciente, que los Chinchorro son descendientes directos de los pescadores de Acha y descartar a priori una posible miscegenación con grupos vecinos alrededor del año 7.000 a.p. Por otra parte, tampoco existe suficiente evidencia que demuestre que las técnicas de embalsamamiento practicada por los Chinchorro tengan un origen altiplánico y/o transaltiplánico. Los modelos planteados hasta el momento para explicar el inicio de técnicas de embalsamamiento no proporcionan una respuesta al hecho que solo algunos cadáveres fueron sometidos al proceso de embalsamamiento. Este hecho pone en duda la idea de que los Chinchorro fueran una sociedad igualitaria y elude una discusión sobre la posible existencia de estratos sociales. Las especiales características de las intervenciones practicadas a los cuerpos de algunos difuntos, podría haber permitido a sus familiares prolongar su muerte social trasladándolos hacia caletas cercanas donde fijaban su residencia temporal. Es probable que la descontinuación de los embalsamamientos estuvo relacionada con la llegada de grupos poblacionales de regiones altiplánicas, que introdujeron en los valles nuevos estilos de vida incluyendo las primeras prácticas agrícolas. Señalamos que la emergencia de tempranas manifestaciones artísticas de naturaleza ideológicas, sin sentido utilitario estricto, es la característica cultural más relevante de los Chinchorro.

Background: The assessment of Attentional Deficit Hyperactivity Disorder (ADHD) among ethnic groups may reveal environmental or cultural variables that influence the appearance of this disorder. Aim: To assess the presence and characteristics of ADHD in two communities of the inland Arica valleys (Azapa and Lluta), where the Aymara population predominates. Material and Methods: Startingfrom a screening based on the Conner's test, we evaluated 79 children aged 8 to 13 years. Sixty children were of Aymara origin and 19 children were of non-Aymara origin. Twenty Aymara and 9 non-Aymara children had ADHD. They were compared with a group of patients from Santiago, Chile (110 children) that were previously assessed. Results: Patientsfrom Azapa/Lluta displayed similar characteristics to those from Santiago. However the former had significantly less psychiatric comorbidities than the latter. On the other hand, the non-Aymara subgroup of Azapa/ Lluta displayed an increased rate of comorbidities and was exclusively of the combined subtype, although their sample size is too small to draw strong conclusions. Conclusions: Although we cannot dismiss biological variables, the importance of family values and the respect to authorities may be protective factors for ADHD, associated to Aymara culture. Our findings suggest that the clinical characteristics of ADHD are not uniform among ethnic groups and cultures. The relative contribution of environmental and genetic factors in this variability remain to be determined.

Background: Worldwide diversity of alleles of D4 receptor gene (DRD4), linked to attention deficit hyperactivity disorder (ADHD), is mostly the result of length and single nucleotide polymorphisms in a 48-bp tandem repeat (VNTR). Alleles containing from two (2R) to eleven (11R) repeats have been identified. The most common are 4R, 7R and 2R. Aim: To study the association of ADHD risk with DRD4 genotypes in Chilean students. Subjects and Methods: ADHD risk data were obtained through the abbreviated Conner's Scale for School Teachers in 66 Aymara children (11 cases and 55 controls), 91 Rapa-Nui children (60 cases ad 31 controls) and 96 children from a mixed urban population from Santiago (51 cases and 45 controls). DNA extracted from saliva was amplified by polymerase chain reaction (PCR) to genotype the DRD4 VNTR. Results: The distribution of DRD4 alleles reveals that, beneath the 4R allele, 7R exhibits the second highest frequencies in Aymara and Santiago children. In Polynesian children, 2R ranks after 4R. A statistically significant association between ADHD risk and 2R/4R genotype was identified in Polynesian children (p < 0.05; odds ratio = 3.7). Conclusions: Different DRD4 genotypes are associated with ADHDphenotype in Chilean populations, probably as a consequence of their initial colonization history.

The study of complex funerary ritual development among hunters and gatherers societies should take into account how people made up for the continuity of their social system without the support of centralized organizations. This research integrates cultural and natural factors to explore how the Chinchorro carried on with their way of life isolated at geographically restricted perennial river mouths with fresh water along the Atacama Desert in the Pacific coast of South America. Within these rather crowded settlings, they created and maintained a social system catalyzed by a complex funerary tradition, embodied by a unique funerary ideological discourse that resulted in the creation of a sacred landscape or "spiritscape". We argue that the extreme hyperaridity of the coastal Atacama Desert (21° - 17.30° S), and the extraordinary biomass production of the marine littoral constituted a fundamental milieu for the maintenance of their long-term social system. The Chinchorro belief system lasted for several millennia (8,000-4,000 BP), but new ways of life and burial practices followed major changes in the coastal ecosystem they relied on, which would have influenced how the "old tradition" was manifested over time. Conversely, we sustain that these natural "constraints" faced by the Chinchorro along the coast of the Atacama Desert, were influential, in the course of their history or the way they socially organized themselves.

Es conveniente que el estudio de rituales funerarios complejos desarrollados por colectividades de cazadores recolectores considere la forma como éstas lograron mantener un sistema social sin la ayuda de organizaciones sociales centralizadas. Este estudio integra factores culturales y naturales para explorar cómo los Chinchorro manejaron su sistema de vida en localidades aisladas y geográficamente circunscritas a un pequeño número de desembocaduras de quebradas con agua fresca y algunas aguadas ubicadas a lo largo de la costa del Desierto de Atacama en América del Sur. En estos asentamientos, más bien sobrepoblados, los Chinchorro crearon y mantuvieron un sistema social caracterizado por una compleja tradición funeraria, representada por un sistema ideológico único que resultó en la creación de un paisaje sagrado o espiritual. Argumentamos que las condiciones de extrema hiperaridez de la costa del Desierto de Atacama (21° - 17.30° S) y la extraordinaria producción de biomasa del litoral marítimo constituyeron pilares fundamentales para la mantención a largo plazo de su sistema social. El sistema de creencias de los Chinchorro se mantuvo por varios milenios (8.000-4.000 a.p.), pero nuevas formas de vida y prácticas funerarias fueron experimentadas después que el ecosistema costero del que dependían sufriera cambios mayorers, que parecen haber dificultado la reproducción de la "vieja tradición". Consecuentemente, concluimos que los constreñimientos naturales de la costa del Desierto de Atacama fueron influyentes en el curso de la historia y la manera como los Chinchorro se organizaron socialmente.

For decades anthropologists have discussed how and when the Americas were peopled. The prevailing view is that the first Paleoindians, ancestors of the Amerindians, arrived from Asia and Beringia to the American continent using a Pacific coastal route in pre-Clovis times. In this article skeletal remains dated 9000-4000 BP, excavated from archaeological sites in northern, central and southern Chile, were analyzed using geometric morphometric and ancient mtDNA techniques. Results indicate that the ancient cranial material from southwestern South America exhibit a wide range of cranial vault shape variation which is independent of chronology. mtDNA restriction and sequence analysis performed on the same skeletal remains, revealed only the presence of the main four founding mtDNA haplogroups (A, B, C and D) as early as 9,000 BP. Our results using morphometric and molecular mtDNA haplogroup data show that human populations inhabiting the Americas during archaic times can not be considered as belonging to two different groups on the basis of analyzed data. These results are consistent with those recently obtained using complete sequence mtDNA analyses.

Durante décadas los antropólogos han discutido cómo y cuándo América fue poblada. El punto de vista predominante al respecto plantea que los primeros paleoindios, población amerindia ancestral, llegó en una época pre-Clovis desde Asia y Beringia utilizando como ruta la costa pacífica del continente. En el presente trabajo se analizan mediante morfometría geométrica y técnicas de ADNmt antiguo restos esqueletales de 9.000-4.000 años a.p., excavados de sitios arqueológicos del Norte, Centro y Sur de Chile. Nuestros resultados muestran que el material craneano arcaico del suroeste de América exhibe un amplio rango de variación de la forma de la bóveda, la cual es independiente de la cronología de los cráneos. El análisis del ADNmt realizado en los mismos restos esqueletales revela la presencia sólo de los cuatro haplogrupos fundadores (A, B, C y D) desde los 9.000 a.p. Los resultados obtenidos a partir de datos morfométricos y de mtDNA muestran que, considerando los rasgos analizados, las poblaciones humanas que habitaron América durante la época arcaica no constituyen dos grupos diferentes. Estos resultados son consistentes con los análisis de secuencias completas de DNA mitocondrial recientemente obtenidos.

Background: Attention deficit/hyperactivity disorder (ADHD) is a common, highly heritable neurobiological disorder of childhood onset, characterized by hyperactivity, impulsiveness or inattentiveness. Aim: To search for differences in risk for ADHD and its components among Chilean native and mixed populations and to look forpossible associations with dopamine receptor D4 (DRD4) and dopamine transporter 1 (DAT1) polymorphisms. Material and Methods: School teachers were requested to complete the Conners test, which uses DSM-IV criteria, to screen for ADHD risk among Aymara and Rapa-Nui students. Results: Rapa-Nui children from Easter Island had the highest risk of hyperactivity/impulsiveness. Aymara children from the Arica-Parinacota Region had lower scores. Although inattentiveness scores had lower differences between groups, overall ADHD score differences among studied populations were highly significant. DRD4 and DAT1 alleles had a heterogeneous distribution. Easter islanders had more divergent frequencies, mostprobably as a result of separate migration routes utilized at different timeperiods during the colonization of America and Polynesia. Conclusions: The comparison of ADHD risk parameters between Rapa-Nui and Aymara children showed marked differences. Allele distri-bution of dopamine polymorphisms in Easter Island was also significantly different from northern Chile, due probably to different colonization histories. These findings suggest that higher ADHD risk scores in Easter Island children may be linked to the presence of different DRD4 alleles.

Archaeological, ethnohistorical, and hioanthropological data from Late Intermediate and Late Periods (ca. A.D. 1,000-1,530) was cross-examined to evaluate whether people of the Lluta Valley organized their economy under the Third Case of John Murra model ofVerticality. To do this, we focused on the chaupiyunga sector a geographic ethnocategory of high valuation in the system of the ecological tiers between the coast and highlands, for its productive qualities and geographic connectivity. The cultural composition of this basin located in the western valleys sub area, of the South Central Andes was compared of what has been observed in the Chillón valleys, in the Central Andes. The archaeological arrangement in both zones combines a variety of cultural ceramic style components. While the Lluta valley shows a mixture of items from the lowlands, sierra, altiplano and Inka, the Chillón basin integrates coastal, chaupiyunga and high-Andean elements. For the Lluta case funerary and rock ark features. XVI and XVII century ethnohistorical sources, of different level of specificity, coincide for both regions the interrelation of several social entities. It is important to note that the heterogeneous scenario of the chaupiyunga is observed in similar ecological zones in Southern Peru, which contrasts with the homogeneity of the lower sections of the valleys. The state of the art does not allow to precise the mechanisms of interaction and complementarity to explain the variability of the archaeological records. First there is not correspondence with the idea of multiethnic "islands " differentiated by particular set features among themselves. On the contrary, the material is mixed in each of the studied sites, which seem to mean that several mechanisms of interaction were simultaneously or sequentially functioning. We conclude that chaupiyunga was a multiethnic ecological space co-habited, visited and or lead by social groups of diverse origin that access to this productive zone under different mechanisms of complementarity and interaction, which may have included verticality (with is modalities of coastal verticality, decentralized micro verticality, centralized vertical archipelago), horizontality simple exchange operations, military protection, married alliances through the exchange of spouses.

A partir de la confrontación de datos arqueológicos, etnohistóricos y bioantropológicos de los períodos Intermedio Tardío y Tardío (ca. 1.000-1.530 d.C), se evaluó si las poblaciones del valle de Lluta se organizaron económicamente bajo el Tercer Caso de Verticalidad de John Murra. Para ello centramos la atención en el sector chaupiyunga, etnocategoría geográfica de alta valorización en el sistema vertical de pisos ecológicos entre la costa y el altiplano. Se caracterizó la situación cultural en esta cuenca ubicada en la subárea Valles Occidentales del Centro Sur Andino y se comparó con la situación del valle de Chillón, Andes Centrales. El panorama arqueológico en ambas zonas integra una amplia variedad de componentes culturales que, en el caso del Lluta, comprende una mezcla de elementos de tierras bajas, sierra, altiplano e Inka, mientras que en el Chillón confluyen rasgos costeros, chaupiyunga y altoandinos. En el caso del Lluta, se agregan rasgos funerarios y de arte rupestre. Para ambas zonas, pero con distintos niveles de especificidad las fuentes etnohistóricas también señalan la concurrencia de varias entidades sociales. Lo importarte es que este heterogéneo escenario del chaupiyunga se repite en otras zonas chaupiyunga del sur de Perú y contrasta con los sectores bajos de los valles que tienden a ser culturalmente más homogéneos. El estado actual del conocimiento arqueológico no permite señalar con precisión el o los mecanismos concretos de interacción o complementariedad que expliquen la variabilidad observada en el registro arqueológico. Primeramente, éste no se corresponde con la idea de islas multiétnicas diferenciadas entre sí por conjuntos de rasgos propios. Por el contrario, los restos materiales de los diferentes componentes o referentes culturales aparecen mezclados en cada uno de los sitios, por lo que pueden representar varios mecanismos de interacción social que funcionaron paralela y secuencialmente. Se concluye que el chaupiyunga fue un espacio multiétnico, cohabitado, visitado y/o liderado por grupos sociales de distinto origen, que se hicieron presente en este ambiente productivo bajo distintos mecanismos de complementariedad o de interacción, que pudo incluir entre otros verticalidad (con sus modalidades de verticalidad costera, microverticalidad descentralizada, archipiélago vertical centralizado), horizontalidad, simples operaciones de intercambio de productos, protección militar y alianzas matrimoniales a través del intercambio de esposas o esposos.

Sophisticated molecular genetics techniques allow the typification and posterior comparison of antique haplogroups and mitochondrial DNA sequences from prehistoric groups with contemporary populations. This adds a chronological dimension to these studies and contributes to have a better knowledge of the genetic composition of the Chilean population. This article gives scientific support, using molecular methodology, to the alleged biological links that joined the descendants of proto historic Chango fishermen from Puposo cove, a place located 15 kilometers north of Taltal, with prehistoric fishermen from Chinchorro culture, that developed in Northern Chile and Southern Peru between 7900 and 4000 A.C.