Genetic admixture estimates by Alu elements in Afro-Colombian and Mestizo populations from Antioquia, Colombia.

AIM: This work was intended to gain insights into the admixture processes occurring in Latin American populations by examining the genetic profiles of two ethnic groups from Antioquia (Colombia). SUBJECTS AND METHODS: To analyse the genetic variability, eight Alu insertions were typed in 64 Afro-Colombians and a reference group of 34 Hispanics (Mestizos). Admixture proportions were estimated using the Weighted Least Squares and the Gene Identity methods. The usefulness of the Alu elements as Ancestry Informative Markers (AIMs) was evaluated through differences in weighted allelic frequencies (delta values) and by hierarchical analysis of the molecular variance (AMOVA). RESULTS: The Afro-Colombian gene pool was largely determined by the African component (88.5-88.8%), but the most prominent feature was the null contribution of European genes. Mestizos were characterized by a major European component (60.0-63.8%) and a comparatively low proportion of Amerindian (19.2-20.7%) and African (17.0-19.3%) genes. Five of the Alu loci examined (ACE, APO, FXIIIB, PV92 and TPA25) showed an adequate resolving power to differentiate between continental groups, as indicated by delta values and AMOVA results. CONCLUSIONS: The peculiarity of the Afro-Colombian gene pool seems to be associated with intense genetic drift episodes that occurred in isolated communities founded by small groups of runaway slaves. ACE, APO, FXIIIB, PV92 and TPA25 could be efficiently utilized in studies dealing with demographic history and biogeographical ancestry in human populations.

Evaluación del polimorfismo por microsatélites en individuos de Piaractus brachypomus (Characidae, Serrasalminae) provenientes del río Meta, Colombia / Polymorphism evaluation by microsatellites in individuals of Piaractus brachypomus (Characidae, Serrasalminae) from Meta river, Colombia

En este estudio, cuatro microsatélites (Pme4, Pme5, Pme20, Pme21) fueron utilizados para tipificar treinta individuos de Piaractus brachypomus, provenientes del río Meta, tributario de la cuenca del río Orinoco. Los resultados mostraron un promedio de cuatro alelos por locus; se reportan seis alelos nuevos (Pme5202, Pme5204, Pme20201, Pme20211, Pme20217 y Pme21258), no descritos en la especie de referencia Piaractus mesopotamicus; el valor promedio de heterocigosidad esperado fue de 46.8 por ciento y el observado de 54.2 por ciento. El grupo de individuos no estuvo afectado por fenómenos genéticos de poblaciones como entrada o salida de individuos, mutación o selección artificial. Estos microsatélites podrían ser utilizados para el análisis genético en esta especie, dentro de los programas de conservación y selección de reproductores en zonas de cultivo.