Williams, Evelyn , FARRAR, DONALD R .
Population genetics and structure in morphologically diverse species of Botrychium s.s. (Ophioglossaceae).
Species in the genus Botrychium s.s. have underground gametophytes, which promote self-fertilization and high rates of inbreeding. This suggests that populations should be divergent, with individuals either selfing or outbreeding with physically close individuals. However, previous research on population structure in the genus and sister genera Botrypus and Sceptridium found consistent patterns of relatively high polymorphic loci, low population differentiation (FST),and high fractions of genetic variation occurring within populations. We used 207 AFLP loci to examine population structure of diploids Botrychium pallidum and Botrychium lanceolatum angustisegmentum and allotetraploid Botrychium matricariifolium in the Upper Peninsula of Michigan. FST was low (< 0.15) for each species, while genetic variation was high (AMOVA, >85%) within populations versus among populations. Analyses with the program STRUCTURE found no differentiation based on sampling location. The lack of population structure suggests rare but effective long-distance spore dispersal, as geographic distance and genetic distance were correlated for the diploid species. Genetic variation within populations of B.matricariifolium was not correlated with the wide range of morphological variation present. In addition, allotetraploid B. acuminatum individuals did not form distinct populations and were included in B. matricariifolium populations.The lack of correlation between genetics and morphology across multiple B. matricariifolium populations is found using allozymes as well. Using ten enzyme systems and 22 loci, we found no patterns that corresponded to morphotypes, including B. acuminatum, within B. matricariifolium. Although populations of B. matricariifolium and allotetraploid B. michiganense were genetically similar using AFLPs, allozyme analysis revealed parental differences between the two species. The complimentary use of AFLPs and allozymes confirmed patterns of population genetics and informed species delineation in this genus.
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1 - Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL, 60022, USA
2 - Iowa State University, Biology Dept, 353 Bessey Hall, Ames, IA, 50011, USA
long distance dispersal
Presentation Type: Oral Paper:Papers for Sections
Location: Union E/Hyatt
Date: Monday, July 9th, 2012
Time: 10:15 AM