PARENT SESSION
OOS 1: Genetic Explorations of the Seascape: Using Molecules and Experiments to Understand Marine Biodiversity.
Organized by: E Sotka and R Thacker
Monday, August 2, 8:00 AM to 11:30 AM, Meeting Room E 141 .

Testing for adaptive population divergence in the tidepool copepod Tigriopus californicus.

Edmands, Suzanne^*,1, ¹ University of Southern California, Los Angeles, CA, USA

ABSTRACT- Despite seemingly high potential for dispersal, populations of the tidepool copepod Tigriopus californicus show extreme molecular differentiation over short geographic distances. For example, populations only 10 km apart can have up to 17% divergence in mitochondrial DNA. Two lines of evidence suggest that this high level of molecular differentiation is accompanied by relatively low levels of adaptive differentiation. First, fitness measurements under common garden conditions show significant effects of environment (temperature and salinity effects), but no significant population x environment interactions. Second, molecular population subdivision for 5 microsatellite markers was found to be considerable higher than quantitative trait subdivision for life history and morphometric characters (F_ST = 0.80, Q_ST = 0.30). The unusual pattern in T. californicus might be attributed to either restricted quantitative evolution or enhanced molecular evolution, both of which may be related to the harsh and variable physical conditions of the high intertidal habitat.

Key words: adaptation, stress, copepod, molecular