Data from: Understanding the evolutionary potential of epigenetic variation: a comparison of heritable phenotypic variation in epiRILs, RILs and natural ecotypes of Arabidopsis thaliana

Increasing evidence for epigenetic variation within and among natural
plant populations has led to much speculation about its role in the
evolution of plant phenotypes. However, we still have a very limited
understanding of the evolutionary potential of epigenetic variation, in
particular in comparison to DNA sequence-based variation. To address this
question, we compared the magnitudes of heritable phenotypic variation in
epigenetic recombinant inbred lines (epiRILs) of Arabidopsis thaliana–
lines that mainly differ in DNA methylation but only very little in DNA
sequence – with other types of A. thaliana lines that differ strongly also
in DNA sequence. We grew subsets of two epiRIL populations with subsets of
two genetic RIL populations, of natural ecotype collections, and of lines
from a natural population, in a common environment and assessed their
heritable variation in growth, phenology and fitness. Among-line
phenotypic variation and broad-sense heritabilities tended to be largest
in natural ecotypes, but for some traits the variation among epiRILs was
comparable to that among RILs and natural ecotypes. Within-line phenotypic
variation was generally similar in epiRILs, RILs and ecotypes. Provided
that phenotypic variation in epiRILs is mainly caused by epigenetic
differences, whereas in RILs and natural lines it is largely driven by
sequence variation, our results indicate that epigenetic variation has the
potential to create phenotypic variation that is stable and substantial,
and thus of evolutionary significance.