Hauk, Warren , Gibson, K. , Masters, T. .
An evaluation of genetic variation in Sceptridium biternatum and S. lunarioides using ISSR markers.
Species of Sceptridium, commonly called the grapeferns, are found through much of North America, with the continental center of diversity in the Eastern United States. Of the four Sceptridium species with distributions reaching the Gulf Coast, S. biternatum is perhaps the most widely recognized and commonly encountered. S. lunarioides is less common, in part because its prostrate growth form makes it inconspicuous. Although assessments of genetic variation have been conducted on more northern Sceptridium species, little information is available about the amount and patterning of genetic variation in southern species. To assess genetically based variation in S. biternatum and S. lunarioides, we sampled populations across much of the ranges of the two species and used ISSR (Inter-Simple Sequence Repeat) markers to assess within-species genetic variation. For each species we surveyed, three ISSR primers generated approximately 30 reproducible loci. In S. biternatum, Bayesian analyses (Hickory 1.0) produced an estimate of FST of 0.30 and of FIS of 0.88. Preliminary neighbor joining (NJ), maximum parsimony (MP), and UPGMA cluster analyses showed that individuals from a single population did not associate consistently with other members of the same population or geographic region. In S. lunarioides, Bayesian analyses produced an estimate of FST of 0.53 and of FIS of 0.60. NJ, MP, and UPGMA cluster analyses that individuals from a single population were more likely to associate with other individuals from the same population or geographic region. Thus, analyses of ISSR data showed evidence of genetic structuring in S. lunarioides, and less evidence of genetic structuring in S. biternatum. Based on Bayesian FIS estimates, S. biternatum is predominately inbreeding, and S. lunarioides may have a more mixed breeding system.
1 - Denison University, Department of Biology, Granville, Ohio, 43023, USA
Presentation Type: Paper
Location: Superior B (Cliff Lodge)
Date: Monday, August 2nd, 2004
Time: 3:45 PM