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HOW DISCRETE ARE OAK SPECIES? INSIGHTS FROM A HYBRID ZONE BETWEEN QUERCUS GRISEA AND QUERCUS GAMBELII
Daniel J. Howard,
Ralph W. Preszler,
Joseph Williams,
Sandra Fenchel,
William J. Boecklen,
Daniel J. Howard
Department of Biology, New Mexico State University, Las Cruces, New Mexico, 88003
Search for more papers by this authorRalph W. Preszler
Department of Biology, New Mexico State University, Las Cruces, New Mexico, 88003
Search for more papers by this authorJoseph Williams
Department of Biology, New Mexico State University, Las Cruces, New Mexico, 88003
Department of Genetics, University of Georgia, Athens, Georgia, 30602
Search for more papers by this authorSandra Fenchel
Department of Biology, New Mexico State University, Las Cruces, New Mexico, 88003
Search for more papers by this authorWilliam J. Boecklen
Department of Biology, New Mexico State University, Las Cruces, New Mexico, 88003
Search for more papers by this authorDaniel J. Howard,
Ralph W. Preszler,
Joseph Williams,
Sandra Fenchel,
William J. Boecklen,
Daniel J. Howard
Department of Biology, New Mexico State University, Las Cruces, New Mexico, 88003
Search for more papers by this authorRalph W. Preszler
Department of Biology, New Mexico State University, Las Cruces, New Mexico, 88003
Search for more papers by this authorJoseph Williams
Department of Biology, New Mexico State University, Las Cruces, New Mexico, 88003
Department of Genetics, University of Georgia, Athens, Georgia, 30602
Search for more papers by this authorSandra Fenchel
Department of Biology, New Mexico State University, Las Cruces, New Mexico, 88003
Search for more papers by this authorWilliam J. Boecklen
Department of Biology, New Mexico State University, Las Cruces, New Mexico, 88003
Search for more papers by this authorAbstract
The white oaks Quercus gambelii and Q. grisea overlap in distribution in New Mexico and Arizona. Within the region of overlap, there are numerous instances of contact between the two taxa. In some areas of contact morphologically, intermediate trees are common, whereas in others, morphologically intermediate trees are rare or absent. We describe a set of RAPD markers that distinguish between the two species and use these markers to examine patterns of gene exchange in an area of contact in the San Mateo Mountains of New Mexico. The markers are highly coincident with morphology and confirm that hybridization between the two species takes place. Despite the occurrence of hybrids, both species remain distinct, even in areas of sympatry, and marker exchange appears to be limited.
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