Chapter 5: Experimental Evolutionary Domestication Pedro Semōes, Josiane Santos, Margarida Matos Presentation by Priya Singha, UC, Irvine

Some questions for you to think about: O What is domestication? How do different factors influence domestication? O What do we know about fruit fly (Drosophila) and it’s domestication? O What is the best way to study evolution in domestication?

Egyptian domestication of animals: Domestication is the longest running experimental evolution project On The Origin of Species: Darwin’s study of pigeon and dog domestication. Domestication: Selection directed to a single goal. Evolutionary change Human controlled environment

Drosophila as a model organism for evolutionary experiments Drosophila repleta O High genetic variation O Allows characterization of evolutionary dynamics at local adaption O Convergent and divergent evolution O Comparative approach and real-time studies O Some disagreements among studies

Evolutionary domestication: Real-time studies in Drosophila subobscura Phylogeny tree of the populations used Experiment design: O 5 populations were used from different times of foundation (NB, NW, TW, AR, FWA) O One generation = 28 days O Control of medium, temperature and population density was carried out. O Population sizes ~1200

Results: Graph for fecundity Long-term evolutionary domestication Fecundity: O Clear, though not very quick, process of adaptivity in early fecundity Starvation resistance: O Old population (NB) shows decline– due to inbreeding depression? O No significant change in new populations Graph for starvation resistance

Shorter-term effects: Fecundity: O Significant linear improvement O Comparison of 2001 population with 1998’s pattern Starvation resistance: O No significant temporal change compared to old populations Results: Therefore, generalizing from shorter-term studies may be misleading. This explains disparities in results at different studies of domestication.

Conclusion of real-time studies O Clear adaptation to laboratory condition is reached. This is indicated by steady increase in early fecundity. O Inbreeding depression may play a role in changes in domestication. O Long-term studies show that old population reach an adaptive plateau (shown by decline in evolution rate) O Odd feature: FEMALE STARVATION RESISTANCE

Comparative studies of domestication O It uses comparison of laboratory adaptation versus analysis preciously discussed. O They compare populations which have been in the labs versus the ones recently introduced from the wild. O They do not give data on evolutionary dynamics. Tree of Life Source: Wikipedia

Examples of comparative studies: O Woodworth et al (2000) Effects of both adaptation and inbreeding during evolutionary domestication Benign and wild conditions O Latter and Mulley (1995) Effects of adaptation and inbreeding on reproductive ability in competitive and non-competitive environments

GENERAL ISSUES: O Complex evolutionary trajectories O Application to conservation Lab Wild

Lessons in domestication from experimental evolution: