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Molecular Analysis of Nyssa sylvatica |
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Molecular Analysis of Nyssa sylvatica in Eastern North America: a Systematic Study on Species History, Postglacial Dispersal, and Species Phylogeny
Nyssa sylvatica (Cornaceae) is a common deciduous tree species found in temperate forests ranging in the eastern United States from Maine to Florida and as far west as Texas. Commonly referred to as black gum, N. sylvatica occurs in the Piedmont, Coastal, and Mountain ecosystems within the Carolinas. Several varieties have been recognized for this species.
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Nyssa biflora Nyssa sylvatica |
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However, this phenotypic information is inadequate to distinguishamoung the varieties, and between N. sylvatica and N. biflora, which often overlap in geographical range. In this study, we compare sequences of DNA regions from both chloroplast and nuclear genomes to help clarify the relationships among these taxa. We have examined several DNA regions from these genomes, including matK, trnH-K, antR, leafy, and ITS. The sequence data will be analyzed using phylogenetic and population genetic methods to deduce the species evolutionary history and gene flow to uncover the genetic divergence among similar ecotypes, and to examine the species delineation. |
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Distribution of Nyssa sylvatica
(from Kenneth W. Outcalt)
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This sampling also includes a variety of Nyssa species including many from the eastern United States and eastern Asia for testing the species boundary. DNA sequences from the same species are expected to be more closely related to one another than they are to other species, which is tested by using phylogenetic analysis and constructing phylogenetic trees. Also, post-glacial migration of the species may be deduced by examining the DNA haplotype genealogy to determine areas of refugia and recent colonization.
Through this project we will increase our knowledge in the overall evolutionary history of temperate forests in eastern North America by understanding the evolutionary history and the dispersal patterns of individual species within the temperate forest. Our results will promote a comparative study between the evolution of forests in eastern North America to that in eastern Asia. This comparison is relevant because these two forests have many similar characteristics but have been isolated from each other for millions of years. The end results should provide additional information to better understand the classification and phylogenetic relationships amount varieties of species within this genus.
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