The goal of the proposed research is to gain a better understanding of the demographics of hybrid speciation in the sunflower genus Helianthus. Three homoploid species were formed via hybridization between the same two parental species. It is thought that hybrid speciation in Helianthus may have been facilitated by founder events, but essentially nothing is known about the demography of hybrid speciation in these or other diploid hybrid species.
The specific aims are to 1) use coalescent methods and many loci spread throughout the genome to estimate ancestral effective population sizes and population growth rates in the hybrid species to determine if they conform to expectations of a founder event speciation model; 2) determine levels of introgression between hybrid and parental species and test the hypotheses that introgression rates are correlated with varying selective forces and chromosomal rearrangements in various genomic regions; 3) perform phylogeographic studies of the parental species to test the hypothesis that the introduction of bison to North America contributed to hybrid speciation by increasing dispersal and the potential for isolation in unique habitats; and 4) perform phylogeographic studies of hybrid species to test for range expansion.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
3F32GM072409-02S1
Application #
7469637
Study Section
Special Emphasis Panel (ZRG1-F08 (20))
Program Officer
Haynes, Susan R
Project Start
2005-08-01
Project End
2008-01-31
Budget Start
2007-08-01
Budget End
2008-01-31
Support Year
2
Fiscal Year
2007
Total Cost
$25,214
Indirect Cost
Name
Indiana University Bloomington
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
006046700
City
Bloomington
State
IN
Country
United States
Zip Code
47401
Sambatti, Julianno B M; Strasburg, Jared L; Ortiz-Barrientos, Daniel et al. (2012) Reconciling extremely strong barriers with high levels of gene exchange in annual sunflowers. Evolution 66:1459-73
Strasburg, Jared L; Sherman, Natasha A; Wright, Kevin M et al. (2012) What can patterns of differentiation across plant genomes tell us about adaptation and speciation? Philos Trans R Soc Lond B Biol Sci 367:364-73
Strasburg, Jared L; Rieseberg, Loren H (2011) Interpreting the estimated timing of migration events between hybridizing species. Mol Ecol 20:2353-66
Blackman, Benjamin K; Rasmussen, David A; Strasburg, Jared L et al. (2011) Contributions of flowering time genes to sunflower domestication and improvement. Genetics 187:271-87
Strasburg, Jared L; Kane, Nolan C; Raduski, Andrew R et al. (2011) Effective population size is positively correlated with levels of adaptive divergence among annual sunflowers. Mol Biol Evol 28:1569-80
Blackman, Benjamin K; Strasburg, Jared L; Raduski, Andrew R et al. (2010) The role of recently derived FT paralogs in sunflower domestication. Curr Biol 20:629-35
Strasburg, Jared L; Rieseberg, Loren H (2010) How robust are ""isolation with migration"" analyses to violations of the im model? A simulation study. Mol Biol Evol 27:297-310
Raduski, Andrew R; Rieseberg, Loren H; Strasburg, Jared L (2010) Effective population size, gene flow, and species status in a narrow endemic sunflower, Helianthus neglectus, compared to its widespread sister species, H. petiolaris. Int J Mol Sci 11:492-506
Strasburg, Jared L; Scotti-Saintagne, Caroline; Scotti, Ivan et al. (2009) Genomic patterns of adaptive divergence between chromosomally differentiated sunflower species. Mol Biol Evol 26:1341-55
Strasburg, Jared L; Rieseberg, Loren H (2008) Molecular demographic history of the annual sunflowers Helianthus annuus and H. petiolaris--large effective population sizes and rates of long-term gene flow. Evolution 62:1936-50