Kingston, S. E., University of Maryland College Park, Program in Behavior, Ecology, Evolution, and Systematics, College Park, USA, kingstons@si.edu
Fagan, W. F., University of Maryland College Park, Program in Behavior, Ecology, Evolution, and Systematics, College Park, USA, bfagan@umd.edu
Braun, M. J., University of Maryland College Park / National Museum of Natural History, Smithsonian Institution, College Park / Suitland, USA, braunm@si.edu

GENOME-WIDE LEVELS OF INTROGRESSION AND DIVERGENCE ACROSS MEXICAN TOWHEE HYBRID ZONES

Hybrid zones are unique interfaces that can help us understand both population level and species level evolutionary processes. A genome-scale approach to identifying and quantifying gene flow across hybrid zones is vital, and now possible. Collared and Spotted Towhees (Pipilo ocai and P. maculatus) hybridize along several gradients in montane habitat in Mexico. These hybrid zones are well characterized morphologically, but at a limited number of genetic loci. We completed a genome survey across one hybrid zone transect (n=167 birds in 11 populations) using AFLP markers (377 polymorphic loci). Inferring cline shape parameters from the spatial changes in allele frequency across a hybrid gradient can provide an estimate of variation among loci in introgression. Cline parameters (i.e. width, center) were estimated from the AFLP loci in order to compare among loci and compile a genomic distribution of parameters. The analysis revealed a variety of cline shapes, not just steep, concordant clines. This suggests that some portion of loci in the genome may be free to cross porous species boundaries, while other loci may be restricted by selective pressure.

Oral presentation

Session #:G56
Date: Thursday, 8/7/08
Time: 4:45 PM

Presentation is given by student: Yes