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Centro de Investigaciones Biológicas del Noroeste (CIBNOR) 2013

Análisis de la estructura genética poblacional de la pitaya agria (Stenocereus gummosus) en el Desierto Sonorense

Lozano Garza, Oscar Adrián

Titre : Análisis de la estructura genética poblacional de la pitaya agria (Stenocereus gummosus) en el Desierto Sonorense

Auteur : Lozano Garza, Oscar Adrián

Etablissement de soutenance : Centro de Investigaciones Biológicas del Noroeste (CIBNOR)

Grade : Maestría en Ciencias en el Uso, Manejo y Preservación de los Recursos Naturales 2013

Résumé
Stenocereus gummosus (Englem.) Gibson and Horak is a Mexican endemic columnar cactus with the vernacular name of "sour pitahaya" and a natural distribution in the western half of the Sonoran Desert, mostly found all along the Baja California Peninsula. The plants ofthis region have been scarcely investigated in terms of genetic structure, while speciation and phylogeography for this area have been explained mainly by vicariant events. Although some ofthose events have been recognized by phylogeographical breaks, there is no geological evidence for them, which is why the debate about this matter is opened. The absence of certainty about the reproduction strategy usage for S. gummasus has lead to suspect that its genetic diversity may be compromised because of its clonal reproduction ability. In addition, it has been supposed that the postglacial wanming process could have facilitated a recent northward expansion range to complete its current distribution, as it has been found happens to other plant communities on the north hemisphere. Through the analysis of microsateIlite molecular markers to infer about the population structure of the sour pitahaya, it has been found that its genetic diversity follows a pattern of isolation by distance, coherent with a population expansion with restricted genetic flow by organism dispersa !. No strong structuration due to geographic barriers has been detected, and results al so suggest the participation of long distance dispersal events during the colonization. Even though genetic diversity was higher at the southern peninsular region, a potential model of multiple refugees during the last glacial maximum is discussed.

Mots Clés : Stenocereus gummosus, microsatélites, estructura poblacional

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Page publiée le 13 décembre 2017