Variation in plastic responses to ocean acidification has also been seen in diatoms and dinoflagellates (Kremp et al. 2012).
There is significant intraspecific variation in plastic responses, so that lineage sorting is expected to occur under ocean acidification.
Given the knowledge that there is considerable intraspecific variation in plastic responses, it is prudent that future studies incorporate both intra- and interspecific variation.
This trade-off could result in the evolution of a single, fixed plastic response across a population, variation in plastic responses across genotypes within a population (genotype-by-environment interactions; 'GxE'), or nonplastic, environmental specialist phenotypes (Pigliucci 2001).
In the green alga Ostreococcus tauri, the plastic responses among 16 strains to manipulated pCO2 concentrations were as large as the variation in plastic responses observed between genera (Schaum et al. 2013).
A few of them have considered populations from native and invaded parts of their range to assess whether there are differences in plastic responses to the different environmental conditions encountered in invasive situations.
Based on the results of a common-garden experimental protocol, this timeframe was sufficient to allow for population differences to emerge in plastic responses of several early-life traits to temperature (Haugen and Vøllestad 2000).
This variation in plastic responses within species strongly suggests that there is variation in evolutionary potential within species as well, and that it is important to take intraspecific diversity into account both in physiological and evolutionary studies aimed at understanding natural populations.
We find 27 differentially regulated miRNAs after mating in young flies and 22 in old flies; and 17 miRNAs differentially regulated with aging in virgin flies and 28 in mated flies, with considerable overlap in plastic responses of miRNAs among the four physiological conditions (Additional file 5: Figure S2).
However, differences in plastic responses were higher between environments within origin than gene expression variation between origins for both rearing environments, suggesting that phenotypic plasticity is not the only cause of phenotypic variation in eel, yet its contribution to the process remains overwhelming in front of (epi) genetic differences related to sampling location.
