4GEvolved

4GEvolved, short for Fourth-Generation Evolution, is a theoretical framework describing how adaptive change may arise through interactions across multiple layers and generations. It envisions evolution as a four-stage process in which genetic variation, regulatory network remodeling, epigenetic and non-genetic inheritance, and ecological context feed back into one another to produce rapid phenotypic shifts beyond what single-generation selection would predict.

The term is used in speculative discussions and some models rather than as a formal, widely adopted theory in primary literature. It serves to highlight how non-genetic inheritance and environment-driven feedback can shape evolutionary trajectories over successive generations.

The four components are: (1) genetic variation generated by mutation and recombination; (2) gene regulatory network remodeling that changes how genes are expressed; (3) epigenetic and non-genetic inheritance, including DNA methylation, histone modifications, small RNAs, and cytoplasmic factors; and (4) ecological context and niche construction that alter selection pressures and transmission of inherited states. Interactions among these layers can produce adaptive change across generations, not solely through DNA sequence alterations.

Applications of the concept include discussions of rapid adaptation in microbial populations, plant responses to environmental stress, and host–pathogen coevolution where feedbacks between organisms and their environment influence heritable traits.

Critics caution that empirical support for stable, transgenerational non-genetic inheritance remains contested and that 4GEvolved risks recasting well-established ideas such as phenotypic plasticity, evolvability, and niche construction without clear distinctions. It is typically treated as a heuristic rather than a settled theory.

See also: Evolution; Epigenetics; Niche construction; Phenotypic plasticity; Evolvability.