Abstract
Phenotypic flexibility is critical in determining fitness. As conditions change during ontogeny, continued responsiveness is necessary to meet the demands of the environment. Studies have shown that subsequent ontogenetic periods of development can interact with one another and shape developmental outcomes. The role genetic variation within populations plays in shaping these outcomes remains unclear. Four full-sib families of zebrafish Danio rerio were raised under for dietary regimes: high food rations for 60 days (HH), low food rations for 60 days (LL), high food rations for 30 days followed by low food rations for 30 (HL), and low food rations for 30 days followed by high food rations for 30 (LH). While the low ration diet significantly reduced body length at 30 days, diet was no longer a significant factor at day 60. Only family level variation influenced body length. Furthermore, there was significant family level variation in the manner in which swimming performance responded to fluctuating dietary conditions. Some families increased swimming performance in response to dietary change, while others did not. These results suggest that plastic responsiveness to subsequent environmental changes can be trait specific and vary significantly within populations.
Highlights
Phenotypic plasticity is a critical aspect of organismal development
To elucidate the role genetic variation plays in determining responses to ontogenetic dietary fluctuations, we examined body size and swim performance in the zebrafish Danio rerio
This resulted in four feeding treatments: high food rations for 60 days (HH), low food rations for 60 days (LL), high food rations for 30 days followed by low food rations for 30 (HL), and low food rations for 30 days followed by high food rations for 30 (LH)
Summary
Phenotypic plasticity is a critical aspect of organismal development. As conditions change during ontogeny, continued responsiveness is necessary to meet the demands of the environment. We found that fish tested in normoxia displayed phenotypes that were altered by development in early hypoxia. Numerous studies have demonstrated that plastic responses vary across genotypes (DeWitt and Scheiner, 2004). This variation provides the raw material for selection to optimize developmental plasticity (West-Eberhard, 2005). Much of our current understanding of the genetics of developmental plasticity comes from studies tracking genotypes across one instance of environmental change. As the environment can change multiple times during ontogeny, it becomes increasingly important to characterize the role genetic variation plays in more complex environments
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