Genomic Signatures for Domestication in European Seabass (Dicentrarchus
labrax L.) Underscoring a Potential Key Role for Epigenetic Regulation
in Adaptation to Captivity
Abstract
Genome scans offer a comprehensive method to explore genome-wide
variation associated with traits under study. However, connecting
individual genes to broader functional groupings and pathways is often
challenging, yet crucial for understanding the evolutionary mechanisms
underlying these traits. This task is particularly relevant for
multi-trait processes such as domestication, which are influenced by
complex interactions between numerous genetic and non-genetic factors,
including epigenetic regulation. As various traits within the broader
spectrum of domestication are selected in concert over time, this
process offers an opportunity to identify broader functional overlaps
and understand the integrated genetic architecture underlying these
traits. In this study, we analyzed approximately 600,000 SNPs from a
Pool-Seq experiment comparing eight natural-origin and 12 farmed
populations of European seabass in the Mediterranean Sea region. We
implemented two genome scan approaches and focused on genomic regions
supported by both methods, resulting in the identification of 96
candidate genes, including nine CpG islands, highlighting potential
epigenetic influences. Many of these genes and CpG islands are in
linkage groups previously associated with domestication-related traits.
The most significantly overrepresented molecular function was
‘oxidoreductase activity’. Furthermore, a dense network of interactions
was identified, connecting 22 of the candidate genes. Within this
network, the most significantly enriched pathways and central genes were
involved in ‘chromatin organization’, highlighting another potential
epigenetic mechanism. Altogether, our findings underscore the utility of
interactome-assisted pathway analysis in elucidating the genomic
architecture of polygenic traits and suggest that epigenetic regulation
may play a crucial role in the domestication of European seabass.