Transgenerational Phenotypic Plasticity in Fishes

Abstract

Phenotypic plasticity, which is sometimes referred to as an environmental driven phenotypic variation, is the capacity of a genotype to create a variety of phenotypes under different environmental conditions. It is critical to include both the genetic architecture and environmental sources of phenotypic variation when examining the trait since environmental change can alter the genetic makeup and plasticity of traits. As a capacity for quick genetic adaptation, plasticity is vital in helping organisms to cope with rapidly changing environments. Transgenerational plasticity refers to a parent’s capacity to modify their offspring’s phenotype without introducing genetic modifications into the offspring. The environmental experiences of the parent generation and/or prior generations have an impact on this genotype (TGP). Through this phenotypic transition, offspring can prime their physiology to more closely fit the environmental circumstances. Parents can modify the offspring’s phenotype that is cued by the environmental experiences in parental generation and/or previous ancestors without involving a genetic change in offspring termed transgenerational plasticity (TGP). Offspring are primed to adapt their physiology to the environment through this phenotypic shift. Transgenerational plasticity provides a real-time compensatory response to environmental fluctuations which is likely to be advantageous by increasing the fitness of species since the climate is changing more rapidly than natural selection that can keep up with adaptation. Recently, TGP is increasingly recognised as a mechanism by which organisms can act much quicker in environmental changes. Several studies have reported that parental exposure to environmental stressors has beneficial effects on offspring. Moreover, transgenerational plasticity and immune priming can be used for the development of novel strategies for producing the robust progenies. Enhanced resistance against various pathogens and abiotic stressors can be developed within and even across generations of offspring which will provide a huge possibility for commercial applications in the fisheries and aquaculture sector. Although there is ample proof that the environment has an impact to phenotypic variation, the underlying mechanisms are still not entirely understood. Mechanistically, parental effects and epigenetic inheritance (DNA methylation, histone modifications and RNA-mediated modifications) have been proposed in facilitating the transgenerational plasticity and programming of the offspring. Understanding the molecular processes by which environmental information is received to switch genes for alternate phenotypes in the context of global climate change and disease outbreaks in the culture system is therefore of highest importance. In this chapter, we have introduced the concept of transgenerational phenotypic plasticity, summarised the evidence of transgenerational plasticity in fishes and highlighted the potential molecular mechanisms.