Parental stressor exposure simultaneously conveys both adaptive and maladaptive larval phenotypes through epigenetic inheritance in the zebrafish (Danio rerio)

Abstract

Genomic modifications occur slowly across generations, whereas short-term epigenetic inheritance of adaptive phenotypes may be immediately beneficial to large numbers of individuals, acting as a bridge for survival when adverse environments occur. In the present study, crude oil was used as an example of an environmental stressor. Adult zebrafish (P 0) were dietarily exposed for 3 weeks to no, low, medium or high concentrations of crude oil. The F 1 offspring obtained from the P 0 groups were then assessed for transgenerational epigenetic transfer of oil-induced phenotypes. The exposure did not alter body length, body and organ mass or condition factor in the P 0 groups. However, the P 0 fecundity of both sexes decreased in proportion to the amount of oil fed. The F 1 larvae from each P 0 were then exposed from 3 hpf to 5 dpf to oil in their ambient water. Remarkably, F 1 larvae derived from oil-exposed parents, when reared in oiled water, showed a 30% enhanced survival compared with controls (P<0.001). Unexpectedly, from day 3 to 5 of exposure, F 1 larvae from oil-exposed parents showed poorer survival in clean water (up to 55% decreased survival). Additionally, parental oil exposure induced bradycardia (presumably maladaptive) in F 1 larvae in both clean and oiled water. We conclude that epigenetic transgenerational inheritance can lead to an immediate and simultaneous inheritance of both beneficial and maladaptive traits in a large proportion of the F 1 larvae. The adaptive responses may help fish populations survive when facing transient environmental stressors.

Phenotypic Switching Resulting From Developmental Plasticity: Fixed or Reversible?

“…Yet, the problem with this reversible/correctable semantic conundrum is that the term 'correctable' suggests that the modified phenotype resulting from developmental plasticity is actually sub-optimal (i.e., needs to be 'corrected'). In fact, the modified phenotype emerging from (enabled by) developmental plasticity might, of course, actually be advantageous under current environmental conditions -e.g., Toth and Hettyey (2018); Bautista and Burggren (2019), and Mendez-Sanchez and Burggren (2019). Not being able to resolve this issue here, this essay will nonetheless use the commonly acceptable term reversible with a parenthetical inclusion of correctable to remind the reader of the complexity of developmental plasticity.…”

Impacts of Petroleum, Petroleum Components, and Dispersants on Organisms and Populations

“…Second, what kind of genetic legacy, if at all, does DWH leave? There have been very few studies of the impacts on the heritability of genetic alterations induced by prolonged and widespread oil pollution (e.g., White et al, 1999;Bautista and Burggren, 2019). While some experiments with F 1 and F 2 generations were attempted, results have so far been equivocal.…”

Developmental Physiology: Grand Challenges

“…What emerges is that early life stages have often higher vulnerability to environmental toxicants than at later stages (Incardona and Scholz, 2018 ; Pasparakis et al, 2019 ). Yet, what is also becoming clear is that organisms can develop considerable resilience to toxicants that can transfer to their offspring through non-genetic mechanisms (Vandegehuchte and Janssen, 2014 ; Kishimoto et al, 2017 ; Bautista and Burggren, 2019 ). A challenge, then is to understand the limits and mechanisms underlying inheritance of this toxicant resistance and how this might alter both science and policy involving environmental contamination.…”