Click image to view a full-sized image. Twelve pairs of T. californicus populations that span a broad range of genetic and geographic distance were hybridized in the laboratory, and fitness components were measured in parents, F1 hybrids and F2 hybrids. Click image to view a full-sized image. Results of the 12 crosses show that both the non-recombinant F1 female backcrosses and the recombinant F1 male backcrosses show a decline in fitness relative to parentals. This implies that coadapted gene complexes may extend beyond single chromosomes, which may make outbreeding depression more difficult to purge than has often been assumed.
Future work is directed at further characterizing the extent of coadaptation.
Click image to view a full-sized image. Hybridization between populations is not always bad for fitness. In some cases it can increase fitness, making interpopulation transfers an important management tool. In collaboration with computer programmer Charles Timmerman we developed a computer model which can be used to test the consequences of population mixing using different parameters. Click image to view a full-sized image.