Offspring development and life‐history variation in a water flea depends upon clone‐specific integration of genetic, non‐genetic and environmental cues

Abstract

Summary1. Theory predicts that offspring developmental strategies involve the integration of genetic, non-genetic and environmental 'cues'. But it is unclear how cue integration is achieved during development, and whether this pattern is general or genotype specific. 2. In order to test this, we manipulated the maternal and offspring environments of three genetically distinct clones of the water flea Daphnia magna taken from different populations. We then quantified the effect that the genotype, maternal environment and the offspring environment had on the development and life histories of the three different clones. 3. Mothers responded to the same maternal environments in different ways, resulting in clonespecific maternal effects on neonate size. Offspring responses to maternal cues varied according to the trait in question and were also clone specific. The integration of these maternal effects during development was highly context dependent in two clones but more consistent across environments in the third. 4. Genetic, non-genetic and environmental cues contributed to offspring phenotypic variation in all three clones, but there was no general pattern linking traits to specific cues. In fact, two clones used different combinations of cues at different points in development to achieve similar phenotypic outcomes. Reaction norms for the age and size at which maturation was initiated differed among genotypes, between maternal environments and across current environments. Developmental transitions such as the decision to mature may thus play an important role in determining patterns of cue integration. 5. Considering multiple traits during development demonstrated that variation in the integration of genetic, non-genetic and environmental cues was an important determinant of life-history variation among D. magna genotypes. This variation is likely to influence phenotypic evolution.

Chromatin structure changes in Daphnia populations upon exposure to environmental cues – or – The discovery of Wolterecks “Matrix”

“…It's developmental dynamics [24] and even the genes that are differently expressed [25] are now known. It is also recognized that genetic, non-genetic and environmental elements interact to bring about phenotypic variation in daphnia populations [26], a phenomenon that is probably applicable to all eukaryotes and that we have recently conceptualized as a systems biology view on inheritance [27]. Daphnia possess bearers of epigenetic information such as modified histones [28], and DNA methylation [29] of the classical mosaic type [30].…”

Chromatin structure changes inDaphniapopulations upon exposure to environmental cues – or – The discovery of Wolterecks “Matrix”

“…(Rozenberg et al 2015)) are now known. It is also recognized that genetic, non-genetic and environmental elements interact to bring about phenotypic variation in daphnia populations (Harney et al 2017), a phenomenon that is probably applicable to all eukaryotes and that we have recently conceptualized as a systems biology view on inheritance (Cosseau et al 2016). Daphnia possess bearers of epigenetic information such as modified histones (Robichaud et al 2012), and DNA methylation (Kvist et al 2018) of the classical mosaic type (Aliaga et al 2019).…”

Embryogenesis plasticity and the transmission of maternal effects in Daphnia pulex

“…The incorporation of nongenetic mechanisms into evolutionary thinking is changing our assumptions about how populations respond to rapid environmental change (Bonduriansky 2012;Hallsson, Chenoweth, & Bonduriansky, 2012), and driving an incentive to understand how the integration of genetic, nongenetic, and environmental cues during development generate persistent phenotypic variation that we observe in offspring and later descendants (Bonduriansky & Day, 2018;Day & Bonduriansky, 2011;Leimar & McNamara, 2015). From an empirical perspective, parthenogenetic organisms are useful for studying the integration of developmental cues, because genetic and nongenetic effects can easily be separated, and large numbers of genetically identical individuals can be reared across different environments and over multiple generations (Harney, Paterson, & Plaistow, 2017;Harris, Bartlett, & Lloyd, 2012;Plaistow, Shirley, Collin, Cornell, & Harney, 2015). As a result, there is already a large body of work in Daphnia demonstrating that parental effects influence the life histories of offspring in various ways including effects on offspring size (Glazier, 1992;Harney et al, 2017), offspring size and age at maturity (Harney et al, 2017), inducible predator defenses (Tollrian, 1995), strain-specific immunity (Little, O'Connor, Colegrave, Watt, & Read, 2003), mode of reproduction (LaMontagne & McCauley, 2001), the development of resistance to heavy metals (Bossuyt & Janssen, 2003) and pesticides (Brausch & Smith, 2009), and the onset and rate of senescence (Plaistow et al, 2015).…”

“…From an empirical perspective, parthenogenetic organisms are useful for studying the integration of developmental cues, because genetic and nongenetic effects can easily be separated, and large numbers of genetically identical individuals can be reared across different environments and over multiple generations (Harney, Paterson, & Plaistow, 2017;Harris, Bartlett, & Lloyd, 2012;Plaistow, Shirley, Collin, Cornell, & Harney, 2015). As a result, there is already a large body of work in Daphnia demonstrating that parental effects influence the life histories of offspring in various ways including effects on offspring size (Glazier, 1992;Harney et al, 2017), offspring size and age at maturity (Harney et al, 2017), inducible predator defenses (Tollrian, 1995), strain-specific immunity (Little, O'Connor, Colegrave, Watt, & Read, 2003), mode of reproduction (LaMontagne & McCauley, 2001), the development of resistance to heavy metals (Bossuyt & Janssen, 2003) and pesticides (Brausch & Smith, 2009), and the onset and rate of senescence (Plaistow et al, 2015). However, the mechanisms linking parental environment and/or state to offspring phenotypic variation remain unknown.…”

“…After leaving the maternal brood pouch, neonates still have to grow and mature, and genetic, nongenetic, and environmental cues all contribute to this process (Harney et al, 2017). However, a mechanistic understanding of the clone-specific integration of developmental cues (Harney et al, 2017) requires the ability to link changes in parental environments or states to changes in egg development patterns and the effect that this then has on offspring phenotypic variation. To date, studies of Daphnia embryogenesis have focussed on the staging of development (reviewed in Mittmann, Ungerer, Klann, Stollewerk, & Wolff, 2014;Toyota et al, 2016) and ecotoxicity testing (Sobral et al, 2001).…”