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United States Department of Agriculture

Agricultural Research Service

Title: Microsatellite DNA Variation in Iris Hexagona Walter

Authors
item MEEROW, ALAN
item Gideon, Michael - GOULDS, FL
item Clayton, Jason

Submitted to: Botanical Society of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: July 5, 2003
Publication Date: August 3, 2003
Citation: Meerow, A.W., Gideon, M., Clayton, J.R. 2003. Microsatellite DNA variation in Iris hexagona walter. Botanical Society of America Proceedings.

Interpretive Summary: Iris hexagona is reportedly the only native iris species in Florida. It is a member of the section Hexagonae, a small complex of 4-5 species and numerous hybrid populations known popularly as Lousiana iris. I. hexagona occurs mostly in open, freshwater swamps in Texas, Louisiana, Mississipi, Alabama, Georgia, South Carolina and Florida, although this broad range assumes synonomy of I. giganti-caerulea with I. hexagona. I. hexagona achieves its broadest geographic range in Florida, occurring throughout the peninsula. One of us (M.G.) has observed populations of this species throughout Florida, and has documented much broader variation in morphology and habitat than has been previously associated with this species. He has identified unusual populations in Highlands County, Florida that occurs in much drier habitats than usually associated with the species. We have a developed a DNA marker library from I. hexagona. Currently, we have completed a survey of 30 populations of the species, 27 from Florida and 3 from Louisiana using these markers. Populations of I. hexagona within any major Florida drainage system represent unique genetic assemblages then radiated from refuges during inter-glacial periods of flooding when Florida was reduced to a series of islands. I. hexagona has also been influenced by pre-Columbian human migration patterns in the state.

Technical Abstract: Iris hexagona is reportedly the only native iris species in Florida. It is a member of the section Hexagonae, a small complex of 4-5 species and numerous hybrid populations known popularly as Lousiana iris. I. hexagona occurs mostly in open, freshwater swamps in Texas, Louisiana, Mississipi, Alabama, Georgia, South Carolina and Florida, although this broad range assumes synonomy of I. giganti-caerulea with I. hexagona. I. hexagona achieves its broadest geographic range in Florida, occurring throughout the peninsula. One of us (M.G.) has observed populations of this species throughout Florida, and has documented much broader variation in morphology and habitat than has been previously associated with this species. He has identified unusual populations in Highlands County, Florida that occurs in much drier habitats than usually associated with the species. We have a developed a microsatellite DNA library from I. hexagona. Currently, we have completed a survey of 30 populations of the species, 27 from Florida and 3 from Louisiana, across 8 SSR loci. An additional sixteen loci are in process. Our hypothesis is that populations of I. hexagona within any major Florida drainage system represent unique genetic assemblages then radiated from refugia during inter-glacial periods of indundation when Florida was reduced to a series of islands. It is also possible that the northernmost populations within the state represent unique and perhaps more resent entries from contiguous states, while southern Florida populations may have radiated from relict populations that survived on highland islands during the last period of inundation. Moreover, we hypothesize that I. hexagona has also been influenced by pre-Columbian human migration patterns in the state. We will present the results of analysis of our data across these 30 populations.

Last Modified: 9/10/2014
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