Revista de Biología Tropical (Mar 2008)
Diversidad genética y relaciones de parentesco de las poblaciones silvestres y cultivadas de pejibaye (Bactris gasipaes, Palmae), utilizando marcadores microsatelitales
Abstract
Se evaluó la diversidad genética en cuatro microsatélites de ADN de pejibaye (Bactris gasipaes Kunth) para relacionarlos con su evolución y domesticación. Se analizaron 258 muestras procedentes de siete poblaciones silvestres y once razas cultivadas. Todos los loci eran polimórficos y se identificaron 50 alelos en total. La diversidad genética fue alta (0.67). Todas las poblaciones reunidas obtuvieron una alta diferenciación genética (Fst=0.16), pero cuando se separaron en poblaciones occidentales y orientales fue menor (Fst=0.13 para ambas). El flujo genético presente en las poblaciones occidentales fue mayor (Nm=1.71) que en las orientales (Nm=1.62). Por otra parte, se encontró que las razas de Putumayo, Yurimaguas, Vaupés, Tucurrique, y Guatuso aparentemente han sido sometida a una intensa selección humana. Además, la existencia de poblaciones híbridas es el resultado del intercambio entre pueblos del neotrópico e introgresiones con poblaciones silvestres y cultivadas. Se estimó la distancia genética Dm para generar un dendograma por el método del vecino más cercano. Definimos tres grupos de poblaciones: Maracaibo (B. caribaea, B. macana var veragua y B. macana var arapuey), Amazonía Oriental (Tembe, Pará y Acre) y el grupo compuesto por dos subgrupos, Occidental (Azuero, Chontilla, Tuira, Cauca, Tucurrique y Guatuso) y Alto Amazonas (B. dahlgreniana, Puerto Ayacucho, Solimões, Vaupés y Putumayo). La relación genética coincide con la hipótesis de que la palmera del pejibaye ha sido domesticada independientemente por lo menos en tres regiones.Genetic diversity and kin relationships among wild and cultivated populations of the pejibaye palm (Bactris gasipaes, Palmae) using microsatellite markers. The genetic diversity of the peach palm (Pejibaye, Bactris gasipaes Kunth) was evaluated using four nuclear DNA microsatellites in an effort to elucidate the evolution and domestication of this crop. A total of 258 samples from seven wild populations and eleven races were analyzed. All loci were polymorphic and a total of 50 alleles were identified. Average genetic diversity (0.67) and genetic differentiation among populations (Fst=0.16) were high when all populations were considered. Genetic differentiation was lower when the populations were grouped according to their origin into Western and Eastern populations (Fst=0.13 for both). Gene flow was slightly higher among Western populations (Nm=1.71) than among Eastern populations (Nm=1.62). The Putumayo, Yurimaguas, Vaupés, Tucurrique and Guatuso races seem to have been subjected to intense human selection. Hybrid populations exist in Azuero, Tuira, Cauca, vaupés, Puerto Ayacucho and Solimões, probably resulting from exchange and introgressions among sympatric wild and cultivated populations. Genetic distance (Dm) was estimated to determine the degree of relationship among populations using the neighbor-joining method; the wild populations from Maracaibo were used as the outgroup. The populations were divided into three general groups: Maracaibo (B. caribaea, B. macana var veragua and B. macana var arapuey), Eastern Amazon (Tembe, Pará and Acre) and a third group with two subgroups, Western (Azuero, Chontilla, Tuira, Cauca, Tucurrique and Guatuso) and Upper Amazon (B. dahlgreniana, Puerto Ayacucho, Solimões, vaupés and Putumayo). The genetic relationships strongly support the hypothesis that peach palm was brought into cultivation independently in no less than three areas: the Western Andes (extending into lower Central America); Upper Amazon (extending into the Solimões and its tributaries), and the Eastern Amazon (extending from Bolivia to the lower Amazon through the Madeira River). Rev. Biol. Trop. 56 (1): 217-245. Epub 2008 March 31.
