Dynamic interplay of maternal and paternal contributions to offspring phenotype in Eurasian perch.

Parental contributions to offspring phenotype extend beyond genetic inheritance, encompassing non-genetic factors that influence early development. However, the interplay between maternal and paternal effects remains poorly understood. This study investigates these contributions in Eurasian perch (Perca fluviatilis) - a valuable model to study parental effect in finfishes - by analyzing early life traits and transcriptomic profiles of larvae resulting from crosses between wild and domesticated parents. Maternal effects dominated key developmental traits, including hatching success, growth, and swim bladder inflation. Transcriptomic analysis revealed a complex regulatory interplay, with 573 genes under exclusive maternal control, while no genes were solely influenced by paternal input. Maternal-effect genes were primarily associated with metabolic, developmental, and stress-response pathways, shaping early larval physiology. Further analysis identified Eurasian-perch-specific candidate maternal-effect genes, such as crtac1, slc16a7, cox5b, kdr, cald1, and bin2, highlighting their potential role in early development. Although paternal contributions were limited, a subset of genes exhibited conditional paternal influence, suggesting a nuanced parental interplay in gene expression regulation. These findings challenge the traditional perspective of strictly coordinated parental contributions, instead revealing a dynamic parental interplay over gene expression and offspring traits. The dominance of maternal effects suggests a primary role in shaping early development, while paternal factors may modulate expression patterns in a context-dependent manner. This study enhances our understanding of parental effects in fish, providing valuable insights for aquaculture breeding strategies and evolutionary biology research.