Estado actual del conocimiento sobre el perfil genético de la población de Costa Rica

The population of Costa Rica has been considered historically as the product of the amalgamation of three ethnic groups: Europeans, Africans and Amerindians. In addition, it has been said that this population is highly inbred, mainly in the central regions of the country. In order to analyze these aspects of historical origin and the constitution of Costa Rica population, we have been conducting a series of studies that aim to unravel the genetic structure of that population. The results show that the Costa Rican population is certainly trihybrid, similar to those of other countries in Latin America, but differing from them in the proportions of gene flow from the ancestral populations. We found that while some specific regions inside the Central Valley maintain a high average inbreeding coefficient, the general trend towards a temporary decline over time. The percentage of inbreeding (alpha) remains high, but in general is not correlated positively with the alpha value. That suggest the existence of moderate emigrations and more unions between couples with the same geographical origin, but not consanguineous unions.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Velvet Worms (Onychophora) in Folklore and Art: Geographic Pattern, Types of Cultural Reference and Public Perception

Aims: To document and preserve folkloric beliefs and art inspired by velvet worms (Onychophora), rare invertebrates that are considered “living fossils”, have full placental organs and capture prey with a rough “net” built in a fraction of a second. Study Design: This study is a combination of field interviews, online surveys and automatic database search. Methods: We asked open-ended questions to farmers who know the worms, consulted experts and searched the Internet to document folkloric and artistic instances using all the names that these animals receive in English, Spanish and Portuguese (languages of the countries where they occur) as well as other languages, and automatic image search, in Web of Science, CrossRef, Google Scholar and Google. Results: We found more than 80 cases of direct references to velvet worms in folklore and art, mostly from the USA, Australia, Brazil, Costa Rica and New Zealand. Per capita the countries with more cases are New Zealand (24 cases per million inhabitants), Costa Rica (16 cases per million inhabitants) and Australia (3 cases per million inhabitants). The most frequent expressions are cartoons, followed by tourism agencies using velvet worms in their ads, products with velvet worm representations folkloric beliefs, and music bands or songs named after them. In almost all cases the animals are seen in a favorable light, inspiring folklore and art that highlight their extraordinary nature. Conclusion: The unique prey capture mechanism of velvet worms seems to have inspired an unexpected number of artistic and folkloric expressions, preserved for the future in the present article, which starts a totally new line of research: the effect of “living fossils” on human culture.Universidad Nacional de Costa Rica, Project 0095-14.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Caracterização citogenética de lucilia sericata (Meigen, 1826) (diptera: calliphoridae), cepa Bogotá, Colômbia

Introducción: Lucilia sericata es una especie de importancia médica y forense, utilizada en terapialarval para curar heridas crónicas y en estudios médico-legales empleada en la estimacióndel intervalo post mórtem y el traslado de cadáveres. No existen registros de las característicascitogenéticas de esta mosca en el neotrópico. El objetivo principal de este trabajo fue identificarlas características morfométricas cromosómicas y las estructuras primarias del cariotipo, a partirde especímenes de L. sericata de la cepa Bogotá, Colombia. Materiales y métodos: Se tomaronhuevos embrionados, que fueron previamente esterilizados en su superficie, se maceraron y luegofueron sembrados en el medio de cultivo L-15, suplementado con 20% de sfb, e incubados auna temperatura de 28 ºC, sin atmosfera de C02. La preparación de los cromosomas se obtuvo demonocapas celulares semiconfluentes, empleando diversas soluciones: antimitótica (Colchicina),hipotónica (KCl 0,075 M) y fijadora (Carnoy: metanol y ácido acético; 3:1). Se llevó a cabo la técnicade bandeo C para la identificación de regiones cromosómicas de heterocromatina constitutiva.Resultados: Se obtuvieron parámetros morfométricos de cada par cromosómico. El número diploidedel cariotipo obtenido de los cultivos celulares fue 2n = 12; éstos se clasificaron morfológicamente,de acuerdo con patrones previamente establecidos, así: los pares I, II, IV y V fueronmetacéntricos, y el par III fue submetacéntrico. A su vez, el par sexual fue heteromórfico, siendoel cromosoma X metacéntrico y el cromosoma Y submetacéntrico. El bandeo C fue positivo paratodos los pares cromosómicos. Conclusiones: Se establecieron las características citogenéticas deL. sericata, cepa Bogotá, Colombia, relacionadas con número, forma, tamaño, posición del centrómeroy regiones heterocromáticas de los cromosomas.Objective: Lucilia sericata is an important species for medical and forensic purposes, it is used inmaggot therapy in the treatment of chronic wounds and in medical-legal studies for establishingthe post-mortem interval and the transfer of corpses. Currently there are no records of thecytogenetic characteristics of this fly in Neotropical region. The main objective of this study wasto identify morphometric characteristics and primary structures from karyotype of L. sericatastrain Bogota, Colombia. Methods and materials: Embryonated eggs were taken, which werepreviously surface sterilized, macerated and then seeded in L-15 medium culture, supplementedwith 20% fbs and incubated at 28 ºC, without C02 atmosphere. The preparation of chromosomeswas obtained from semiconfluent monolayers, pretreated with various solutions: antimitotic (Colchicine),hypotonic (KCl 0.075 M) and fixative (Carnoy, methanol and acetic acid, 3:1). C-bandingtechnique was carried out to identify chromosomal regions of constitutive heterochromatin.Results: Morphometric parameters were obtained from each pair of chromosomes. The diploidkaryotype number obtained from cell cultures was 2n = 12; they were classified morphologically,according to patterns established previously, as follows: pairs I, II, IV and V were metacentricand pair III was submetacentric. On the other hand, the sexual pair was heteromorphic, beingX chromosome metacentric and Y chromosome submetacentric. C banding was positive for allchromosome pairs. Conclusions: The cytogenetic characteristics of L. sericata, strain Bogotá,were established according to number, shape, centromer position and heterochromatic regions.Introdução: Lucilia sericata é uma espécie de importência médica e forense, utilizada em terapialarval para curar feridas crônicas e em estudos médico-legais empregada na estimação do intervalopost morteme o traslado de cadáveres. Não existem registros das características citogéneticasdesta mosca no neotrópico. O objetivo principal deste trabalho foi identificar as característicasmorfométricas cromossômicas e as estruturas primárias do cariótipo, a partir de especímenes deL. sericata da cepa Bogotá, Colômbia. Materiais e métodos: Tomaram-se ovos embrionados, queforam previamente esterilizados em sua superfície, se maceraram e depois foram semeados nomédio de cultivo L-15, suplementado com 20% de SFB, e incubados a uma temperatura de 28°C, sem atmosfera de C02. A preparação dos cromossomas obteve-se de monocamadas celularessemiconfluentes, utilizando diversas soluções: antimitótica (Colchicina), hipotônica (KCl 0,075M) e fixadora (Carnoy: metanol y ácido acético; 3:1). Levou-se a cabo a técnica de bandas C paraa identificação de regiões cromossômicas de heterocromatina constitutiva. Resultados: Se obtiveramparâmetros morfométricos de cada par cromossômico. O número diplóide do cariótipoobtido dos cultivos celulares foi 2n = 12; estes se classificaram morfologicamente, de acordo compatrões previamente estabelecidos, assim: os pares I, II, IV e V foram metacêntricos, e o par IIIfoi submetacêntrico. Por sua vez, o par sexual foi heteromórfico, sendo o cromossoma X metacêntricoe o cromossoma Y submetacêntrico. As bandas C foram positivas para todos os parescromossômicos. Conclusões: Se estabeleceram as características citogenéticas de L. sericata, cepa Bogotá, Colômbia, relacionadas com número, forma, tamanho, posição do centrômero e regiõesheterocromáticas dos cromossomas

Parturition in onychophorans: new record and a review.

artículo (arbitrado) -- Universidad de Costa Rica. Escuela de Biología, 1988El parto en una especie costarricense de Epiperiparus tiene la siguiente secuencia: la madre presenta peristalsis y un hinchamiento del gonoporo, los lobopodios terminales se levantan y el neonato empieza a salir, a lo que ayuda caminando, una gota de material blanco se expele por el gonoporo. El neonato puede trepar al dorso de la madre. Cuatro juveniles midieron entre 1.2 y 1.8 mm, y pesaron entre 0.010 y 0.017 g, lo que representa en promedio el 5.9% del peso de la madre. Durante las primeras seis semanas los juveniles tienen un color más claro que los adultos. El parto en los onicóforos presenta una secuencia de eventos relativamente constante en el taxón, requiere entre 10 y 30 minutos y su frecuencia parece estar regulada por las condiciones ambientales. La distribución sistemática de los tipos de reproducción sugiere una creciente tendencia hacia el aumento de la inversión paterna.Parturition in a Costa Rican species of Epiperipatus has the following sequence: the mother shows peristalsis and a swollen gonopore, the terminal lobopods are raised and the neonate walks out, a drop of white material is expelled by the gonopore. The young may crawl to the mother’s back. Four young measured 1.2-1.8 1m in length and weighed 0.010-0.017 g (mean, 5.9% of mother’s weight). During the first six weeks young are more lightly coloured than adults. In onychophorans, the parturition sequence is relatively constant throughout the taxa, requires 10-30 mm and its frecuency appears to be influenced by environmental conditions. The systematic distribution of modes of reproduction suggests an increasing tendency towards greater parental investment.Universidad de Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Análisis de varios marcadores genéticos clásicos en la población de Costa Rica

Artículo científico -- Universidad de Costa Rica, Instituto de Investigaciones en Salud. 2001A study of several loci blood groups (ABO, Diego, Duffy, Kell, Kidd, Lewis, Lutheran, MNSs, P, Rhesus and Secretor), and Hp serum protein was carried out on a sample of 2 196 unrelated Costa Rican individuals of both sexes. Data was classified and analyzed according to geographic regions. Gene frequencies and the goodness of fit to Hardy-Weinberg equilibrium were estimated by the maximum likelihood method. A geographic structuring was observed in the Costa Rican population. All the regions of Costa Rica show higher heterozigosity values than the ones observed in the indigenous Costa Rican groups, but similar or slightly higher than the ones observed in the Spanish populations. The genetic distance analysis evidenced that the regions of Costa Rica group close to each other in intermediate positions between the Amerindians and the Spanish, fact that is coherent with the statement that atributes a intermediate origin to the general population of Costa Rica. The data contradicts the idea that the Central region has a radically different population than the rest of the country. The outcome of these markers revealed poor values of exclusion probability in forensic and paternity cases, which confirms the importance of their replacement for DNA markers in the outlines of human identification of judicial investigation systems. These results are similar to other studies made in Latin American populations.Se realizó un estudio de varios loci de grupos sanguíneos (ABO, Diego, Duffy, Kell, Kidd, Lewis, Lutheran, MNSs, P, Rhesus y Secretor) y de la proteína sérica haptoglobina en una muestra de 2 196 costarricenses no emparentados y de ambos sexos. Los datos fueron clasificados y analizados de acuerdo con la región geográfica de origen de los individuos. Se estimaron las frecuencias génicas y su bondad de ajuste al equilibrio de Hardy-Weinberg mediante el método de máxima verosimilitud. Se observó la existencia de una estructuración geográfica en la población de Costa Rica. Todas las regiones de Costa Rica presentan valores de heterocigosidad mucho mayores a los observados en los pueblos indígenas costarricenses, pero semejantes o ligeramente mayores a los encontrados en poblaciones de España. El análisis de distancias génicas evidenció que las regiones de Costa Rica se agrupan próximas entre sí, en posiciones intermedias entre las amerindias y las de España, hecho que es coherente con el planteamiento que atribuye un origen mestizo a la población general de Costa Rica. Además, los datos contradicen la idea de que la región Central tiene una población radicalmente diferente a las demás regiones del país. Estos marcadores revelan pobres valores de probabilidad de exclusión forense y de paternidad, lo que confirma la importancia de su reemplazo por marcadores de ADN en los esquemas de identificación humana de los sistemas de investigación judicial. Tales resultados son similares a los encontrados en otras poblaciones latinoamericanas.Universidad de Costa Rica, Instituto de investigaciones en SaludUniversidad de Costa Rica, Laboratorio Clínico Clodomiro PicadoUniversitat Pompeu Fabra, Barcelona, Unidad de Biología Evolutiva, Departamento de Ciencias de la Salud y de la VidaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

La genealogía de doña Isabel Jiménez. Una aproximación a la primera fase del mestizaje en Costa Rica

artículo (arbitrado) -- Universidad de Costa Rica. Escuela de Biología, 2012The genealogy of doña Isabel Jiménez is a evidence of Spanish-Amerindian admixture since the early Spanish Colony in Costa Rica. The observed a DNA lineage wich has an Amerindian ancestry in a a deep matrilineal genealogy. Such results point out that an Amerindian gene flow had occurred into the Spanish group during the first generations of colonial society. This conclusion do not support the current idea that the Spanish elite avoided interethnic marriages.Universidad de Costa Rica, Escuela de Biología y Centro de Investigaciones en Biología Celular y Molecular. GICYT (España), concesiones PB95-0267-C02-01 y PB98-1064. Generalitat de Ctalunya, Group de Rebeca Consolidat2000GR00093. Beca de la Agencia Española de Cooperación Internacional (AECI).UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Unexplored Character Diversity in Onychophora (Velvet Worms): A Comparative Study of Three Peripatid Species

Low character variation among onychophoran species has been an obstacle for taxonomic and phylogenetic studies in the past, however we have identified a number of new and informative characters using morphological, molecular, and chromosomal techniques. Our analyses involved a detailed examination of Epiperipatus biolleyi from Costa Rica, Eoperipatus sp. from Thailand, and a new onychophoran species and genus from Costa Rica, Principapillatus hitoyensisgen. et sp. nov.. Scanning electron microscopy on embryos and specimens of varying age revealed novel morphological characters and character states, including the distribution of different receptor types along the antennae, the arrangement and form of papillae on the head, body and legs, the presence and shape of interpedal structures and fields of modified scales on the ventral body surface, the arrangement of lips around the mouth, the number, position and structure of crural tubercles and anal gland openings, and the presence and shape of embryonic foot projections. Karyotypic analyses revealed differences in the number and size of chromosomes among the species studied. The results of our phylogenetic analyses using mitochondrial COI and 12S rRNA gene sequences are in line with morphological and karyotype data. However, our data show a large number of unexplored, albeit informative, characters in the Peripatidae. We suggest that analysing these characters in additional species would help unravel species diversity and phylogeny in the Onychophora, and that inconsistencies among most diagnostic features used for the peripatid genera in the literature could be addressed by identifying a suite of characters common to all peripatids.This study was supported by a Ph.D. fellowship of the Conselho Nacional de Desenvolvimento Cientı´fico e Tecnolo´gico (CNPq: 290029/2010-4) and by a SYNTHESYS grant (financed by the European Community Research Infrastructure Action - FP7 Integrating Activities Programme: http://www.synthesys.info/) to ISO. GM is a Research Group Leader supported by the Emmy Noether Programme of the German Research Foundation (DFG: Ma 4147/3-1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Oscillation of the velvet worm slime jet by passive hydrodynamic instability

The rapid squirt of a proteinaceous slime jet endows velvet worms (Onychophora) with a unique mechanism for defence from predators and for capturing prey by entangling them in a disordered web that immobilizes their target. However, to date, neither qualitative nor quantitative descriptions have been provided for this unique adaptation. Here we investigate the fast oscillatory motion of the oral papillae and the exiting liquid jet that oscillates with frequencies f~30–60 Hz. Using anatomical images, high-speed videography, theoretical analysis and a physical simulacrum, we show that this fast oscillatory motion is the result of an elastohydrodynamic instability driven by the interplay between the elasticity of oral papillae and the fast unsteady flow during squirting. Our results demonstrate how passive strategies can be cleverly harnessed by organisms, while suggesting future oscillating microfluidic devices, as well as novel ways for micro and nanofibre production using bioinspired strategies