|
|
||||||||
Population Biology |
2Centro 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, 58190 Michoacán, México; 3Centro de Educación Ambiental e Investigación Sierra de Huautla, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, Cuernavaca, 62210, Morelos, México; 4Departamento de Biología, Facultad de Ciencias, Universidad Nacional Autónoma de México, México, D.F. 04510, México
Quercus affinis and Q. laurina are two closely related Mexican red oaks with partially overlapping distributions. Within the area of overlap, there are localities where morphological intergradation occurs. A previous hypothesis explained this pattern as a result of secondary contact between the two species, followed by hybridization and introgression. This possibility was analyzed here by examining foliar and genetic variation in 16 localities situated along a macrogeographic gradient, which included morphologically representative populations of both species and populations from within the area of overlap. Maximum-likelihood hybrid index scores calculated from nine semi-diagnostic RAPD markers indicated a shift in the genetic composition of populations from one species to the other along the macrogeographic gradient, with genetically intermediate populations situated in the area of overlap. Foliar variation followed a partially congruent pattern, but Q. laurina-like morphology predominated in some of the genetically intermediate populations. There were several instances of correlated frequency changeovers of single RAPD markers and morphological characters along the macrogeographic gradient and a few cases of markedly parallel patterns between markers. The results were interpreted as consistent with a hypothesis of secondary contact between the two oak species that has resulted in some differential introgression among markers.
Key Words: hybrid zones hybridization Quercus affinis Quercus laurina RAPD markers
This article has been cited by other articles:
![]() |
F. Gugerli, J.-C. Walser, K. Dounavi, R. Holderegger, and R. Finkeldey Coincidence of Small-scale Spatial Discontinuities in Leaf Morphology and Nuclear Microsatellite Variation of Quercus petraea and Q. robur in a Mixed Forest Ann. Bot., April 1, 2007; 99(4): 713 - 722. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Tovar-Sanchez and K. Oyama Natural hybridization and hybrid zones between Quercus crassifolia and Quercus crassipes (Fagaceae) in Mexico: morphological and molecular evidence Am. J. Botany, September 1, 2004; 91(9): 1352 - 1363. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |