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Universidad Autónoma de Nuevo León (2014)

Variación genética en poblaciones de pinus pinceana del Noreste de México

Aguirre Limón, Verónica Adriana

Titre : Variación genética en poblaciones de pinus pinceana del Noreste de México.

Auteur : Aguirre Limón, Verónica Adriana

Université de soutenance : Universidad Autónoma de Nuevo León

Grade : Doctor en Ciencias con acentuación en Manejo y Administración de Recursos Vegetales UANL, 2014.

Pinus pinceana Gordon is a Mexican pine, which belongs to subsection Cembroides (pinyon pines). Is distributed in mountainous and arid areas in the Sierra Madre Oriental. It is known from at least 21 populations, which are small, restricted, isolated and severely fragmented. They occur in three main areas : Northern, Central and southern parts of its range. Is listed on the Mexican National Red List (Norma Oficial Mexicana) as a rare and a species requiring special protection (NOM.059-ECOL-2001). In order to evaluate the genetic diversity between populations, the gene flow as well as genetic distance of P. pinceana, 180 samples were obtained from Northern localities within its range of distribution in the Sierra Madre Oriental and analysed using random amplified polymorphic DNA (RAPD). The five primers tested for the analysis showed banding patterns with very high reproducibility and clear band resolution. These five primers produce a total of 76 distinct bands, 72 of which were polymorphic across the whole sample. The genetic diversity in the populations was high with a percentage of polymorphism of 94.7% and degree of diversity measured by the Shannon index of 48%. The total variation found between the populations was 14.8% (p = 0.001). Most of the variation was found within populations (85.18). The gene flow measured by the coefficient of migration was 2.76 per generation. Contrary to expectations, the level of genetic variation found in the populations was high but differentiation between them low (Gst 0.15). This suggests that even though the species has a restricted and fragmented distribution through the Sierra Madre Oriental the gene flow between populations has been sufficient to say that P. pinceana is not in a genetic extinction vortex. The genetic distance shows the formation of two groups one with populations from the state of Coahuila and the other with Nuevo Leon and Zacatecas, which indicate a higher gene flow between these, regarding to Coahuila and probably the influence of some physiographic barriers within the Sierra Madre Oriental.


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