Frequency of Hybrids between Introduced and Native Populations of the Salamander Plethodon jordani in Their First Generation of Sympatry
Highton R. 1998. Frequency of Hybrids between Introduced and Native Populations of the Salamander Plethodon jordani in Their First Generation of Sympatry. Herpetologica. 54(2):143-153
Reciprocal transplantation of the southern Appalachian salamander Plethodon jordani between the Great Smoky Mountains and the Balsam Mountains, in field competition experiments by Nelson G. Hairston, Sr. in 1974-1978, provided an opportunity for observing the genetic interactions between the two populations in their first generation of sympatry. Native individuals in both mountain ranges can be identified by their coloration (red cheeks in the Great Smoky Mountain population, gray cheeks in the Balsam Mountain population) and F1 hybrids can usually be identified by diagnostic alleles at four allozyme loci that have large frequency differences (>0.8) between the two populations. Based on electrophoretic comparisons of 22 protein loci, the Nei genetic distance between the two populations is 0.27. The frequency of F, hybrids in experimental plots in both mountain ranges was much less than expected from random mating of the two forms, indicating that either strong selection against hybrids or positive assortative mating (or both) occurred in the first generation of sympatry. This result might be expected between populations that are so divergent genetically. Twenty-three of the 32 individuals classified as F1 hybrids possess an average of about half the amount of red on their cheeks as individuals of the pure Great Smoky Mountain P jordani, but in nine individuals the red cheek pigment was absent.
- Type
- Journal Article
- Authors
- Highton, Richard
- Units
- GRSM
- Keywords
- allozymes, Balsam Mountain, deficiency of F hybrids, geographic genetic differentiation, GRSM-00104, Hybridization, Plethodon, Plethodontidae, Salamanders, Taywa Creek
- Subjects
- Ecological Framework: Biological Integrity | Focal Species or Communities | Amphibians and Reptiles