Rebekah A. Mohn Miami University, Oxford, Ohio mohnra@miamioh.edu Mentor: Christine E. Edwards
• “A separately evolving metapopulation lineage” where lineage refers to an “ancestor -descendent lineage.” (De Queiroz, 2007) De Queiroz. 2007. Systematic Biology
D. exaltatum distribution from USDA Plants Database • The Appalachian and Ozark disjunction. (400 miles) • Causes of disjunction: • Long-distance dispersal • Glaciation • Recolonization from refugia • A hot and dry period following glacial retreat Raven. 1972. Annals of Botany
D. exaltatum distribution from USDA Plants Database Delphinium exaltatum Aiton • Perennial herb with disjunct distribution. • Flowers insect pollinated and self-compatible. • Seeds are gravity or water dispersed. • Conservation status: vulnerable.
• How is genetic variation structured in Delphinium exaltatum ? • What biogeographical factors have affected patterns of genetic structure? • Do patterns of genetic structure reflect the disjunction between the two groups of Delphinium exaltatum? • Is there evidence that D. exaltatum may contain more than one species?
• Null hypothesis: Genetic structure does not reflect the disjunction between the two groups of Delphinium exaltatum. • Genetic structure reflects the disjunction between the two groups of Delphinium exaltatum supporting distinction taxonomically of the two groups.
Abbr. Voucher County, State n a MO1 S. Farrington, et al. 12-16 (MO) Howell, MO 22 MO2 E. Haglund, et al. OZAR 43809 (ONSR*) Shannon, MO 24 MO3 E. Haglund, et al. OZAR 43810 (ONSR*) Shannon, MO 24 MO4 G. Yatskievych, et al. 12-054 (MO) Shannon, MO 17 MO5 G. Johnson, et al. s.n. (MO) Shannon, MO 10 NC1 Y. Johnson s.n. (MO) Watauga, NC 22 NC2 Y. Johnson s.n. (MO) Durham, NC 22 PA1 S.P. Grund 6219 (MO) Huntington, PA 13 TN1 R. Cook s.n. (MO) Anderson, TN 23 VA1 A. Hyduke, et al. 11 (MO) Montgomery, VA 21 WV1 P. J. Harmon, et al. 3490 (MO) Mecer, WV 23
Microsatellite : Small base pair repeats in the nuclear DNA. Locus : A specific microsatellite (or other genetic fragment) that is usually isolated with a primer. Diploid : every individual has two alleles per locus. Allele : The number of base pairs at a microsatellite. Homozygote : an individual with two of the same allele. Heterozygote : an individual with two different alleles. PCR : Polymerase Chain Reaction.
Results Data Analysis • Structure Data Scored • Clumpak • Microsatellites scored • MSA • Genepop DNA amplified • BOTTLENECK • PCR • INEST • Yale analyzed • Arlequin • FSTAT DNA extraction • Genodive • CTAB Sample collection
Genetic Divergence
Genetic Divergence Figure A: Distribution map with structure results. Figure B: K=2 through K=5 Structure results.
Genetic Divergence An unrooted tree calculated with Nei’s genetic distance
Genetic Divergence MO1 MO2 MO3 MO4 MO5 NC1 NC2 PA1 TN1 VA1 WV1 Obs. MO1 0 MO2 0 MO3 0 MO4 0 MO5 0 NC1 0 NC2 0 PA1 0 TN1 0 VA1 0 WV1 0 Patterns of pairwise genetic structure in D. exaltatum. The genetic distance calculated by Jost’s D is reported above the diagonal (P67 was not included in the Jost’s D calculation)
Genetic Divergence Obs. MO1 MO2 MO3 MO4 MO5 NC1 NC2 PA1 TN1 VA1 WV1 MO1 0 0.219 0.103 0.057 0.069 0.676 0.572 0.623 0.298 0.700 0.606 MO2 0.219 0 0.107 0.258 0.289 0.709 0.491 0.697 0.323 0.771 0.819 MO3 0.103 0.107 0 0.145 0.180 0.714 0.508 0.674 0.402 0.778 0.754 MO4 0.057 0.258 0.145 0 0.150 0.660 0.548 0.632 0.247 0.677 0.575 MO5 0.069 0.289 0.180 0.150 0 0.794 0.472 0.952 0.388 0.786 0.766 NC1 0.676 0.709 0.714 0.660 0.794 0 0.819 0.248 0.716 0.280 0.243 NC2 0.572 0.491 0.508 0.548 0.472 0.819 0 0.639 0.307 0.682 0.755 PA1 0.623 0.697 0.674 0.632 0.952 0.248 0.639 0 0.629 0.377 0.247 TN1 0.298 0.323 0.402 0.247 0.388 0.716 0.307 0.629 0 0.490 0.530 VA1 0.700 0.771 0.778 0.677 0.786 0.280 0.682 0.377 0.490 0 0.114 WV1 0.606 0.819 0.754 0.575 0.766 0.243 0.755 0.247 0.530 0.114 0 Patterns of pairwise genetic structure in D. exaltatum. The genetic distance calculated by Jost’s D is reported above the diagonal (P67 was not included in the Jost’s D calculation)
Genetic Divergence Percent of Variation {MO1, MO2, MO3, MO4, MO5} vs. {VA1, WV1, NC1, NC2, PA1, TN1} Among groups 20.06 Among populations within groups 32.28 Within populations 47.66 Percent of Variation {MO1, MO2, MO3, MO4, MO5, TN1, NC2} vs. {VA1, WV1, NC1, PA1} Among groups 40.15 Among populations within groups 17.7 Within populations 42.15
Genetic Divergence • Genetic variation and structure is not according to the biogeographical boundaries and taxonomic distinction based on the disjunction is not supported. • Divergence potentially to the level of speciation may have occurred between {PA1, WV1, VA1, NC1} and {MO1, MO2, MO3, MO4, MO5, NC2, TN1}. • {NC2} has also diverged from {MO1, MO2, MO3, MO4, MO5, TN1}, possibly to the point of distinction.
• {PA1, WV1, VA1, NC1} • Northern • Higher Elevations • Eastern • {NC2, TN1} • {MO1, MO2, MO3, MO4, • Southern MO5} • Lower Elevations • Southern • Eastern • Lower Elevations • Western
East-West Disjunction Long-Distance Dispersal Recolonization from coastal refugia Hot and dry climate • {MO1, MO2, MO3, • {PA1, WV1, VA1, NC1, MO4, MO5} TN1, NC2} • Western • Eastern
• {PA1, WV1, VA1, NC1} • Northern • Higher Elevations Genetic Divergence Appalachian uplift Glaciation • {MO1, MO2, MO3, MO4, MO5, NC2, TN1} • Southern • Lower Elevations
• Genetic Divergence • The genetic structure does not reflect the biogeographical distribution and does not support taxonomic separation of Missouri from the Appalachian populations of Delphinium exaltatum . • Speciation may have occurred between the northern and southern populations. • Future Research • Determine whether morphometric analyses support distinguishing the two groups as separate species. • Add an Ohio population to the genetic analysis to further explain the biogeographic and genetic distributions of various groups.
• Special thanks to Joel Swift, Burgund Bassüner, Alex Linan, George Yatskievych, Peter Hoch, David Bogler, Allison Miller, and the many other individuals who made this program possible. Thanks to NSF for funding and the Missouri Botanical Garden for hosting the REU. • Thank you to Chrstopher T. Frye, Maile Neel, Tanja Schuster, Kerry Wixted, Donald Rohrback, Susan Farrington, Randall J. Evans, Grace Johnson, Dan Drees, Paul McKenzie, Liz Olson, Randy Evans, Erin Haglund, Yari Johnson, Steven Grund, Rebecca Cook, Abigail Hyduke, Tom Wieboldt, Paul J. Harmon, and Jeff Hajenga for collecting the vouchers and samples for DNA.
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