Embryonic canalization and its limits—A view from temperature

Abstract

Many animals are able to produce similar offspring over a range of environmental conditions. This property of the developmental process has been termed canalization—the channeling of developmental pathways to generate a stable outcome despite varying conditions. Temperature is one environmental parameter that has fundamental effects on cell physiology and biochemistry, yet developmental programs generally result in a stable phenotype under a range of temperatures. On the other hand, there are typically upper and lower temperature limits beyond which the developmental program is unable to produce normal offspring. This review summarizes data on how development is affected by temperature, particularly high temperature, in various animal species. It also brings together information on potential cell biological and developmental genetic factors that may be responsible for developmental stability in varying temperatures, and likely critical mechanisms that break down at high temperature. Also reviewed are possible means for studying temperature effects on embryogenesis and how to determine which factors are most critical at the high‐temperature limits for normal development. Increased knowledge of these critical factors will point to the targets of selection under climate change, and more generally, how developmental robustness in varying environments is maintained.

Thermal regime during parental sexual maturation, but not during offspring rearing, modulates DNA methylation in brook charr (Salvelinus fontinalis)

“…The offspring used in this study were sampled at the fry (i.e. early exogenous feeding) stage, thus it is possible that brook charr may exhibit greater plasticity later in development, due to either strong parental effects during early life stages, or developmental canalization resulting in low plasticity during early life [ 88 ]. Other studies have identified long-lasting parental effects on gene expression [ 18 ] and offspring size [ 89 , 90 ] in brook charr, and a related study using Laval strain brook charr identified persistent parental effects on phenotype past stocking [ 57 ].…”

Targeting river operations to the critical thermal window of fish incubation: Model and case study on Sacramento River winter‐run Chinook salmon

“…Nor does it imply that the temperature T fully defines the window duration. Studies indicate that temperature stress weeks before hatching, in the gastrulation phase (Irvine, 2020; Mueller et al, 2015) could alter the efficiency of respiration and cellular development, which in turn could affect the coefficients in Equation ().…”

Thermal regime during parental sexual maturation, but not during offspring rearing, modulates DNA methylation in brook charr (Salvelinus fontinalis)

“…If inherited differences in DNA methylation affect offspring phenotype, epigenetic inheritance due to parental thermal regime could prove adaptive for brook charr due to gradual but predictable warming in Canada, but maladaptive if brook charr are unable to acclimate to and survive transient temperature extremes. The offspring used in this study were sampled at the fry (i.e., early exogenous feeding) stage, thus it is possible that brook charr may exhibit greater plasticity later in development, due to either strong parental effects during early life stages, or developmental canalization resulting in low plasticity during early life [83]. Other studies have identified long-lasting parental effects on gene expression [18] and offspring size [84,85] in brook charr, and a related study using Laval strain brook charr identified persistent parental effects on phenotype past stocking [54].…”