Data from: Proteomic evidence of a paedomorphic evolutionary process within a marine snail species: a strategy for adapting to extreme ecological conditions?

The exposed and sheltered ecotypes of the marine snail Littorina saxatilis
from European rocky shores are considered a key model system to study
adaptation and ecological speciation. Previous studies showed that two
ecotypes (RB and SU) of this species in NW Spain have differently adapted
to different shore levels and microhabitats. In order to understand how
this divergent adaptive process has been accomplished, we followed a
quantitative proteomic approach to investigate the proteome variation in a
number of different biological factors, i.e. ecotype, ontogeny and their
interactions. This approach allowed testing the hypothesis that one of the
ecotypes has evolved by paedomorphosis, and also whether or not the
molecular mechanisms related to ecotype differentiation are set up in
early developmental stages. Additionally the identification of some
candidate proteins by mass spectrometry provides some functional insights
about these evolutionary processes. Results from this study provided
evidence of higher ontogenetic differentiation at proteome level in the RB
(metamorphic) than in SU (paedomorphic) ecotype that point to the
possibility of juvenile stage retention in this latter ecotype. The level
of protein expression (proteome) differences between ecotypes maintained
nearly constant from late embryonic stages to adulthood, although some
proteins involved in these changes considerably differed in embryonic
compared to other ontogenetic stages. Paedomorphosis may be the
evolutionary response of the SU ecotype of solving the trade-off during
sexually immaturity that is caused by the evolution of small size arising
from adaptation to the wave exposed habitat. Some potential candidate
genes of adaptation related to energetic metabolism have been identified,
providing a promising baseline for future functional analyses.