Data from: Experimental evidence of rapid heritable adaptation in the absence of initial standing genetic variation

The success of genetically depauperate populations in the face of
environmental change is contrary to the expectation that high genetic
diversity is required for rapid adaptation. Alternative pathways such as
environmentally induced genetic modifications and non-genetic heritable
phenotypes have been proposed mechanisms for heritable adaptation within
an ecologically relevant timeframe. However, experimental evidence is
currently lacking to establish if, and to what extent, these sources of
phenotypic variation can produce a response. To test if adaptation can
rapidly occur in the absence of initial standing genetic variation and
recombination in small populations, we (i) exposed replicate monoclonal
populations of the microzooplankton Brachionus calyciflorus to a
culturing regime that selected for phenotypic variants with elevated
population growth with either high or low phosphorus food for a period of
55 days and (ii) examined population-level response in two fully factorial
common garden experiments at day 15 and 35 of the exposure experiment.
Within six generations, we observed heritable local adaptation to nutrient
limitation. More specifically, populations with a history of exposure to
P-limited food exhibited higher population growth rates under low P food
conditions than populations with a high P exposure history. However, the
capacity for such a response was found to vary among clones. Our study
finds that although standing genetic variation is considered essential for
rapid heritable adaptation, the rapid emergence of de
novo genetic variation or alternative sources of phenotypic
variation could aid in the establishment and persistence of low diversity
populations.