Transgenerational Effects Across Diverse Environments:A Meta-analysis And An Experimental Study

Our study contained two parts.The first part was a meta-analysis about the anticipatory transgenerational effect.The second part was an experimental study about the transgenerational effect in Arabidopsis thaliana.The definition of the transgenerational effect is the influence of parental environment on offspring phenotype,without any genetic changes.Recent evidences have drawn increasing attention to the transmission of non-genetic information,as understanding the magnitude of non-genet:ic inheritance can help us better understand the mechanisms of adaptation.However,the evidence is equivocal and appears to be context-dependency(i.e.,change across environment and species).To synthesizing the current evidence of non-genetic transmission,we conducted a meta-analysis on the transgenerational effects by characterizing different factors.For instance,we classified environmental contexts as stressful,less stressful(benign),favorable and less favorable conditions(benign).We summarized 1174 effect sizes from 142 studies and contained 114 kinds of species.The main research achievements in meta-analysis:we found that transgenerational effects generally enhanced offspring performance in response to both stressful and more benign conditions.The strongest effects were in annual plants and invertebrates,whereas vertebrates appear to benefit mostly under benign conditions,and perennial plants showed hardly any transgenerational responses at all.These differences among taxonomic/life-history groups possibly because vertebrates could avoid stressful conditions through their mobility,and longer-lived plants had alternative strategies,in particular,greater within-generation plasticity.Besides environmental contexts and taxonomic/life-history groups,the strengths of transgenerational effects also varied among traits and developmental stages of ancestors and offspring,but effects were similarly strong when tested across three generations offspring.Furthermore,transgenerational effects were found significantly impact all three offspring generations in the analysis,with no decay in the effect sizes.Our analyses thus suggested that transgenerational effects were widespread,strong and persistent.Our meta-analysis showed that transgenerational effect could enhance offspring performance across favorable and stress environment in annual plants.To verified this ideal,we employed an experimental study about transgenerational effect by using A rabidopsis thaliana which is an annual model species with a short life-cycle.We were also curious about if the transgenerational effects in Arabidopsis thaliana would respond differently to the environment depend on genetic background.So we selected 14 ecotypes with different phenotype and climate origin.To begin with,we put these ecotypes in the control environment for two generations to get rid of the influence of their origin environment on our experiment result.Then,we cultured these genotypes in 11 kinds of different environments for one generation,their offspring all experienced a control environment.We tested the influence of environment and ecotype on within and trans-generational plasticity.We found that both genetic background and environment influence within generational plasticity,but transgenerational plasticities primarily influenced by genetic background.We observed a strong genotype-specific transgenerational effects and they are not diverse randomly.For the short flowering type(early summer annuals),offspring showed a neutral transgenerational effect in life history trait or delayed flowering.Furthermore,these ecotypes tended to decrease their reproduction output when parents experienced a changing environment.However,for long flowering types(late summer annuals and winter annuals),offspring tended to flower earlier,increase fruits and increase their reproduction output when parents experienced a changing environment.These phenomena could be explained by different life history strategy in genotypes.Genotype-specific transgenerational effect also correlated with Arabidopsis’s origin climate.Genotypes from regions with low precipitation prolonged flowering time after parental drought.Genotypes from regions with large temperature range prolonged flowering time after parental nutrient.Since different genotypes adapted to their origin climate and they might be more tolerant to a climate factor or sensitive to other factors.Thus,genotypes from different climate origin had a different magnitude of transgenerational effects.In meta-analysis,we found that the context-dependency of transgenerational effect was introduced by systematic factors,including environmental contexts of experiments,taxonomic/life-history groups and traits measured.Overall,transgenerational effects were common and beneficial for organisms,particularly for organisms with a fast lifecycle and limited dispersal ability.Furthermore,transgenerational effect could be stable with a few generations,could contribute to rapid adaption in a fluctuating environment.The transgenerational effect in Arabidopsis thaliana demonstrated genotype-specific transgenerational effect could be associated with life history strategies and climate origin.Future study can pay more attention to multigenerational effects,and transgenerational effects in fluctuating environments,especially favorable environments.Our study gave a new aspect to explain the magnitude of genotype-specific transgenerational effects and this still needs more evidence to prove the connection between life history strategies and transgenerational plasticities.