Molecular Ecology and Evolution
Mccauley, Ross A. , Cortes-Palomec, Aurea C. , Oyama, Ken .
Phylogeography and historical gene flow patterns in disjunct Quercus across the Sierra Madre Occidental and southern Cordillera of Mexico.
Quercus L. Section Lobatae Loudon Subsection Racemiflore A. Camus is a small group of four species of Red Oak (Q. conzattii Trel., Q. radiata Trel., Q. tarahumara Spellenb., J.R. Bacon, & Breedlove, Q. urbanii Trel.) extending from Chihuahua to Oaxaca and occurring between 1000 and 2600 m in elevation. The four species are closely related and united by their production of fruits on long racemose inflorescences, a unique trait within the Red Oaks. While the group has a relatively wide distribution it is largely restricted to small habitat "islands" due to an affinity for exposed mineralized soils. Coupled with the patchy occurrence of the group, two species, Q. urbanii and Q. conzattii exhibit widely bicentric distributions. Quercus urbanii exhibits a disjunction in its range of approximately 700 km from mountain slopes near the Balsas Depression to the western Sierra Madre in Sinaloa and adjacent Durango. Extending this pattern further, Q. conzattii exhibits a disjunction of approximately 850 km from its southern area of distribution in the mountains of Oaxaca to the southern Sierra Madre Occidental in northern Jalisco, southern Durango, and western Zacatecas. Using a combination of chloroplast and nuclear microsatellites, we are surveying the genetic variation within 48 populations of the four species of Racemiflorae across the entire range of the group to identify unique species and regional haplotypes. Using this data we can infer phylogeographic patterns and identify regions of high levels of historical gene flow among the four species providing clues to the present day bicentric distribution.
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1 - Centro de Investigaciones en Ecosistemas, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex-Hacienda de San José de la Huerta, Morelia, Michoacán, 58190, México
Presentation Type: Oral Paper:Papers for Topics
Location: Boulevard B/Hilton
Date: Wednesday, July 11th, 2007
Time: 8:45 AM