Evaluación preliminar de la diversidad genética del leoncillo <em>Callithrixpygmaea</em> (Primates: Cebidae: Callithrichinae) mediante microsatélites (SSR: Short Sequence Repeat)

Abstract

The pygmy marmoset (Callithrix pygmaea) is one of the most specialized Ecuadorian primate species. Its high specialization in habitat and diet, and the increase of human activities in the Amazon region may cause pygmy marmosets to go through population bottle necks, losing genetic diversity. To estimate the magnitude of this threat, since 2008 we carried out a pilot study for evaluating the genetic diversity of four wild groups of this species in a population located on the margins of the Aguarico river. For the genetic analyses we used 50 fecal samples collected from September 2008 to February 2009; 50 % of the samples belonged to group P4, groups P1, P2 and P5 provided the remaining 50 %. We extracted DNA from the feces using the QIAamp DNA Stool Mini Kit (QIAGEN). With PCR we amplified 9 microsatellite primers reported for a related species of Callitrichinae. DNA bands were visualized in polyacrylamide (6 %) and urea (5M) gels. Statistical analyses were carried out with GenAlEx 6 software. Three to eight alleles were found per locus. The Hardy-Weinberg equilibrium test suggested that inbreeding may be occurring in group P4. Expected heterocigocity in groups P1 and P2 is 0.5, while in group P4 ranges from 05. to 0.836. Nei's genetic distance between groups P1 and P2 is 1.211, whereas group P4 differs 0.612 and 0.485 from groups P2 and P1, respectively. This is the first study of this type for this species in Ecuador and elsewhere, the results point out the need to evaluate human impact on the genetic diversity of Ecuadorian species. Keywords. Callithrix pygmaea, genetic diversity, microsatellites (SSR). ResumenEl leoncillo (Callithrix pygmaea) es uno de los primates ecuatorianos con mayor grado de especialización de hábitat y de dieta. Esta alta especialización y la intensificación de las actividades humanas en la Amazonía ecuatoriana podrían causar que las poblaciones del leoncillo atraviesen por cuellos de botella y pierdan su diversidad genética. Con el fin de estimar la magnitud de esta amenaza, desde el año 2008, se realizó un estudio piloto para evaluar el nivel de variabilidad genética de cuatro grupos de esta especie de una población a orillas del río Aguarico. Para la realización del análisis genético se utilizó un total de 50 muestras de heces, colectadas durante el período de septiembre 2008 y febrero 2009; el 50 % de las muestras correspondió al grupo P4, los grupos P1, P2 y P5 aportaron con el restante 50 %. A partir de estas muestras se extrajo ADN con el kit QIAamp DNA Stool Mini Kit (QIAGEN). Mediante la técnica de PCR se amplificaron nueve primers de microsatélites reportados para otra especie de Callitrichinae. La visualización de bandas se realizó en geles denaturantes de poliacrilamida al 6 % y Urea 5M. El análisis estadístico fue realizado con el programa GenAlEx 6. Los resultados obtenidos muestran que existen de 3 a 8 alelos/locus, la prueba de equilibrio Hardy-Weinberg sugiere que en el grupo P4 puede estar sucediendo endogamia, la heterocigocidad esperada en los grupos P1 y P2 ...

Conservation ofNeotropical primates:Ecuador – a case study

“…Also in the 1990s, the author with her research team began a long‐term study of several populations of the Pygmy marmoset Callit. pygmaea in northern and central Amazonian Ecuador (de la Torre et al ., , ; de la Torre & Snowdon, , ; Yépez, de la Torre & Snowdon, ; Nieto et al ., ). There have been fewer studies of the primate species that occur west of the Andes.…”

“…This project includes an environmental education and training component for local communities (PRIMENET, ). Finally, in the long‐term study of several populations of the Pygmy marmosets in north‐eastern Ecuador, information has been provided on feeding ecology, communication, reproduction and the effects of tourism, human traffic and forest fragmentation on the demography, behaviour, genetic variability and conservation status of this species (de la Torre et al ., , ; de la Torre & Snowdon, , ; Yépez, de la Torre & Snowdon, ; Nieto et al ., ). Based on this information, Pygmy marmosets were included in the Red List of threatened mammal species of Ecuador in 2011.…”

“…A pioneer study of habitat preferences and basic demography of the primate community in the Cuyabeno Reserve was carried out by Ulloa (). Research with Hapalinae species has provided information about habitat use, diet, social organization, reproductive behaviour, communication and conservation status of Pygmy marmosets (de la Torre et al ., , ; de la Torre & Snowdon, , ; Yépez, de la Torre & Snowdon, ; Nieto et al ., ), Graell's tamarins Sag. graellsi (de la Torre et al ., ) and Golden‐mantled tamarins Sag.…”

“…All the studies mentioned previously were based on field work. To date, very few studies have combined laboratory and field work to analyse the genetic variability of primate species (di Fiore, ; Nieto et al ., ), and there are no reports of studies carried out with captive populations (such as populations in zoos). This bias against laboratory and research in captivity could be partially explained by the higher economic and logistic costs of these types of studies, which involve the maintenance of captive populations and the acquisition of specialized equipment, compared with the relatively lower costs and high possibility of observing and studying wild primate populations in their natural habitats.…”

Los primates ecuatorianos, estudios y perspectivas

“…En el 2009 iniciamos un estudio de marcadores moleculares con ADN extraído de heces para evaluar la variabilidad genética en esta población de leoncillos y estimar cómo ésta es afectada por la fragmentación de los hábitats. Los resultados de este estudio piloto sugieren que los grupos que están más aislados por la fragmentación muestran una variabilidad genética reducida y una menor heterocigosidad que sugiere la existencia de endogamia [53].…”