Influence Of Maternal Effects Research Articles

Direct and maternal genetic parameters for growth traits in Jersey crossbred cattle

Abstract Growth data on Jersey crossbred calves, maintained at ICAR-National Dairy Research Institute, Eastern Regional Station, Kalyani, Nadia, West Bengal, India, were collected and analysed to assess the influence of maternal effects on growth traits of calves. Traits considered for this study were birth weight (BW) and weights at 3 months (W3M), 6 months (W6M), 9 months (W9M) and 12 months (W12M) of age. Least-squares analyses were employed to obtain the effects of non-genetic factors on the traits of interest. Determination of influence of maternal effects on growth traits was estimated by fitting three univariate animal models (including or excluding maternal effects) using Bayesian approach. The most appropriate model for each trait was selected based on Deviance Information Criterion. Direct heritability (h2) estimates for BW, W3M, W6M, W9M and W12M were 0.31 ± 0.08, 0.26 ± 0.10, 0.48 ± 0.10, 0.44 ± 0.11 and 0.39 ± 0.14, respectively, under the best model. Permanent environmental maternal effects (c2) varied from 0.04 to 0.12 for all traits. Existence of maternal effects for all ages reflects the importance of maternal components for these traits. Moderate to high heritability estimates for growth traits indicate the possibility of modest genetic progress for these traits through selection under prevalent management system.

Influence of maternal effects and temperature on fecundity of Sebastes fasciatus on the Flemish Cap

The conservation of a sufficient reproductive potential of an exploited stock is one of the goals of fisheries management, as it ensures sustainable productivity. However, there is evidence that spawning stock biomass (SSB) does not represent well the variation in stock reproductive potential, often leading to impaired stock-recruitment relationships. In this study we show that fecundity of Sebastes fasciatus on Flemish Cap is not proportional to SSB and shows temporal fluctuation influenced by maternal effects. Females were collected in 23 research surveys between 1996 and 2020. An autodiametric calibration model was developed for S. fasciatus for the first time to estimate fecundity. Mean potential fecundity was estimated as 36000 oocytes and mean relative fecundity as 79 oocytes g–1. Potential fecundity varied significantly with female length, age, condition index, gonadosomatic index and environmental variability. Mixed-effect linear models were fitted to assess the effect of maternal traits and bottom temperature on fecundity. Fecundity increased significantly with condition factor and sea bottom temperature. Relative fecundity also increased significantly with length, age and gonadosomatic index, indicating that older, larger and better-conditioned females produce more eggs per female gram. This suggests that SSB is not a good proxy to stock reproductive potential so it is unsuitable for use in stock assessment and scientific advice. Considering that S. fasciatus is a viviparous species, future research should focus on maternal effects on offspring and on building time series of reproductive potential indexes that take into account maternal effects.

Seed coat colour of Indian mustard [Brassica juncea (L.) Czern. and Coss.] is associated with Bju.TT8 homologs identifiable by targeted functional markers.

Seed coat colour is an important trait in Indian mustard. Breeding for seed coat colour needs precise knowledge of mode of inheritance and markers linked to it. The present study was focussed on genetics and development of functional markers for seed coat colour. F1s (direct and reciprocal) and F2 populations were developed by crossing two contrasting parents for seed coat colour (DRMRIJ-31, brown seeded and RLC-3, yellow seeded). Phenotypic results have shown that the seed coat colour trait was under the influence of maternal effect and controlled by digenic-duplicate gene action. Further, Bju.TT8 homologs of both parents (DRMRIJ-31 and RLC-3) were cloned and sequenced. Sequencing results of Bju.TT8 homologs revealed that in RLC-3, gene Bju.ATT8 had an insertion of 1279bp in the 7th exon; whereas, gene Bju.BTT8 had an SNP (C→T) in the 7th exon. These two mutations were found to be associated with yellow seed coat colour. Using sequence information, functional markers were developed for both Bju.TT8 homologs, validated on F2 population and were found highly reliable with no recombination between the markers and the phenotype. Further, these markers were subjected to a germplasm assembly of Indian mustard, and their allelic combination for the seed coat colour genes has been elucidated. The comparative genomics of TT8 genes revealed high degree of similarity between and across the Brassica species, and the respective diploid progenitors in tetraploid Brassica species are the possible donors of TT8 homologs. This study will help in the marker-assisted breeding for seed coat colour, and aid in understanding seed coat colour genetics more precisely.

Elucidating genotype by environment interaction over the growth trajectory of Malpura sheep in the semi-arid region of India through Random regression model

The Presence of genotype by environment (GxE) interaction over different ages across growth trajectory in different environments leads to alteration in sires ranking, it may cause problem in any breeding program by affecting efficiency of selection. The objective of the present study was to compare the random regression models (RRM) and conventional animal models and also to plot the trajectory of the growth curve using Legendre polynomial (LP) function of the RRM for better genetic evaluation for growth traits of the Malpura sheep. The data was collected from 8299 animals descended from 2529 dams and 525 sires for growth traits of Malpura sheep, selected over 45 years (1975–2019) maintained at the Animal Genetics and Breeding Division, ICAR-Central Sheep and Wool Research Institute (CSWRI), Avikanagar, Rajasthan, India. The Legendre polynomial based random regression models (LP-RRM) was more robust as compared to conventional animal model and it included direct genetic, direct maternal, maternal permanent environmental and animal permanent environmental effects as a random effects in different orders of fit. The estimates for the additive direct heritability (h2) using best LP-RRM (4444) were 0.176 ± 0.022, 0.367 ± 0.024, 0.314 ± 0.021, 0.323 ± 0.023 and 0.314 ± 0.023, respectively for live body weight at birth (BWT), three-month (WWT), six-month (6WT), nine-month (9WT) and twelve-month (12WT). The comparable trends of variances were found in LP-RRM with trends obtained from the inclusive univariate animal model that included the direct genetic, direct maternal and maternal permanent environmental components. The h2 estimates indicated the further scope of genetic improvement through selection. The maternal proportion of variance was accounting for 1–15 % variance across growth trajectory indicating the low influence of maternal effects that reduced significantly post-weaning. However, we observed that the animal permanent environment accounted for 42–58 % of variance across growth trajectory. The estimates of genetic correlation in LP-RRM were positive and higher (mostly >0.80) between most of the time points as compared to the estimates obtained from animal model, indicating less GxE when RRM is used. Currently selection of Malpura sheep is carried out at the age of six month for growth traits. The presence of genotype by environment (GxE) interaction resulted in to significant re-ranking of sires at 12WT on the basis of breeding values using animal model. However, more consistency in sires ranking were found in the reaction norms plotted for breeding values at 6WT and 12WT using LP-RRM. The RRM have property for accounting (GxE) interaction across growth trajectories more precisely. Therefore, it is recommended that the RRM approach should be used for genetic evaluation of Malpura sheep at 6-month age for unbiased, accurate, and consistent prediction of breeding values for growth traits.

Bayesian analysis reveals the influence of maternal effect on pre-weaning body weights in Landlly piglets.

The present study was undertaken to estimate the (co)variance components and genetic parameters of body weights recorded in Landlly piglets from birth to weaning at weekly intervals (w0 to w6). The data pertained to body weights of 2462 piglets, born to 91 sires and 159 dams across different generations during a 7-year period from 2014 to 2020. Five animal models (I-V), differentiated by inclusion or exclusion of maternal effects with or without covariance between maternal and direct genetic effects, were fitted on the data using the Bayesian algorithm. The analyses were implemented by Gibbs sampling in the BLUPF90 program and Markov chain Monte Carlo (MCMC) methodology was used to draw samples of posterior distribution pertaining to (co)variance components. Based on deviance information criteria (DIC), model V with inclusion of direct additive genetic, direct maternal genetic and permanent environmental effect of dam as random factors along with covariance between direct additive and maternal effects best fitted the data on pre-weaning traits (w0 to w5). Whereas, model I incorporating only the direct additive genetic effect best fitted the weaning weight (w6) data in Landlly piglets. The posterior mean estimates of direct heritability under the best models for W0 to W6 were 0.13, 0.19, 0.29, 0.13, 0.26, 0.32 and 0.46, respectively. Inclusion of the maternal component helped in better partitioning of variance for different body weights in Landlly piglets. The maternal heritability ranged from 0.06 to 0.14, while the litter heritability ranged from 0.11 to 0.15 for pre-weaning weights (W0 to W5) under the best-fit models. The influence of maternal environment was greater than maternal genetic effect from birth to 4th week of age. The results implied that variations in body weight of Landlly pigs were genetically controlled to moderate levels (especially w2 and w4) with contributions from direct additive and maternal genotype that can be exploited by designing efficient breeding programmes.

Use of Random regression model for modeling growth trajectory in Jamunapari goat in the semi-arid region of India

The objective of the study was to plot the trajectory of the growth curve in Jamunapari goat using B-spline (BS) function and compare it with the Legendre polynomial (LP) function of the random regression model (RRM) and also to assess the genotype and environment interaction for growth traits. The data was collected from 8763 descendants of 1845 dams and 339 sires. The RRM used direct genetic, direct maternal, permanent environment for animal and maternal permanent environmental effects in different orders of fit. The B-spline model (BSL6H5) was more robust compared to LP-RRM. The heritability (h2) estimates were 0.23 ± 0.03, 0.26 ± 0.02, 0.22 ± 0.02, 0.19 ± 0.02, 0.22 ± 0.02, respectively for birth weight (BW), three-month weight (3MW), six-month weight (6MW), nine-month weight (9MW) and twelve-month weight (12MW) from the best model. The h2 estimate indicated the further scope of genetic improvement through selection. The maternal proportion of variance was accounting for 3 to 8% variance across growth trajectory indicating the low influence of maternal effects that reduced significantly post-weaning. However, we observed that the animal permanent environment accounted for 45 to 69% of variance across growth trajectory. The genetic correlations between 6MW, 9MW, and 12MW were high and positive indicating scope for early selection. The genetic trends at 3, 6, 9, and 12 months of age were 0.065 kg, 0.082 kg, 0.098 kg, and 0.121 kg per year, respectively, indicating a favorable impact of selection for growth traits. The ranks of the sires at different time points based on breeding values through B-spline RRM were more robust as compared with estimates from the conventional animal model and LP-RRM, where the presence of genotype by environment (GxE) interaction resulted in significant re-ranking of sires for 9MW and 12MW. The B-spline RRM approach resulted in a pragmatic solution for the problem of GxE interaction across growth trajectories. We conclude that the B-spline RRM should be used for genetic evaluation of Jamunapari goats in the future for unbiased, accurate, and consistent prediction of breeding values.

Reciprocal differences and combining ability for growth and yield components in cacao (Theobroma cacao L.): a case of recommended cacao varieties in Ghana

The inappropriate use of cacao clones either as female or male parents in seed gardens have been suggested as some of the reasons for the low yields of cacao hybrid varieties grown in West Africa. The concept of reciprocal effects in cacao crosses has not been well studied. To investigate the impact of maternal effect on growth and yield traits, reciprocal differences and combining abilities of recommended cacao parents in Ghana were evaluated. Six clones, comprising four important seed gardens clones used across West Africa and two clones previously used as standards in international breeding projects were crossed in a 6 × 6 complete diallel mating design to produce 30 F1 progenies. These progenies were tested in the field using a random block design with four blocks and elementary plots containing 20 plants. Growth and yield traits including stem cross-sectional area in juvenile stage, jorquette height, bean weight, number of beans per pod and bean yield were monitored over a 6-year period. Mean squares of general combining ability (GCA), specific combining ability (SCA) and reciprocal effects were significant for almost all the traits except jorquette height in SCA. This indicates that additive and non-additive gene effects are important in the inheritance of the traits. The presence of reciprocal differences for all traits suggests the influence of maternal effects in controlling the traits. Manual pollinations for commercial seed production should, therefore, follow established protocol and clones recommended as female and male parents used strictly as recommended. One of the standard clones, AMAZ15/15 had significant positive GCA effect for yield, and consistently produced progenies with high SCA values. It could be added to parental clones currently used in producing cacao varieties in the seed gardens in Ghana and other West African cacao growing countries.

English

Maize is an important cereal crop in sub-Saharan Africa but production is adversely affected by maize streak virus disease (MSVD). In Ghana, re-occurrence of the disease has been reported in several regions, therefore, necessitating the development of resistant hybrids as the most sustainable and economical option. The objectives of the study were to identify parents and hybrids that combine MSVD resistance with high yield and determine the influence of maternal effect on the inheritance of MSVD resistance. To achieve these, five parental inbred lines namely: TZEI-4, TZEI-7, TZEI-22, TZEI-31 and TZEI-157 were crossed in a full diallel mating design during the major season of 2015. The resulting F1 hybrids were evaluated under natural and artificial infestations during the minor and major seasons of 2015/2016 using 9 x 3 alpha-lattice design with three replications. General combining ability (GCA) and specific combining ability (SCA) mean squares were significant for MSVD severity mean score and only SCA for grain yield. Additive gene effect was preponderant for MSVD severity mean score, whereas grain yield was influenced by non-additive gene effect. Maternal effect had no significant contribution to the inheritance of MSVD resistance. GCA by environment and SCA by environment mean squares were significant for MSVD severity mean score. GCA effects revealed that inbreds TZEI-7 and TZEI-22 were resistant to MSVD. They could be good combiners for grain yield in addition to TZEI-31 and TZEI-157. Hybrids TZEI-4*TZEI-22 and TZEI-4*TZEI-31 showed resistance to MSVD as revealed by their SCA effects and heterotic values. TZEI-7*TZEI-157, TZEI-31*TZEI-157, TZEI-22*TZEI-157 and TZEI-4*TZEI-22 had positive and significant SCA effect, mid-parent heterosis and high parent heterosis for grain yield. Promising hybrids TZEI-4*TZEI-22, TZEI-22*TZEI-157, TZEI-7*TZEI-157 and TZEI-31*TZEI-157 identified in this study should be further tested in multi-locations across Ghana to determine their stability and adaptability. Key words: Maize streak virus disease, grain yield, resistance, full diallel, general combining ability, specific combining ability.

Genotype-environment interaction of maternal influence characteristics in Nellore cattle bred in the Brazilian humid tropical regions by reaction norm

Reaction Norm (RN) is the study of genotype-environment interaction (GxE) that complies with alternative ways of genotypes within different environments. This study was carried out to verify GxE by a reaction norm model of weights at 120 (W120) and 210 (W210) days of age in Nellore cattle raised in the Humid Tropical Regions of Brazil. Environmental gradients were obtained by solutions of contemporary groups which were fitted as co-variables in the random regression model via reaction norms. Mean weight at 120 days of age was 127.97 kg, and environmental gradients ranged between -27 and +26 kg. Average was 185.60 kg at 210 days of age and gradients ranged from -54 to +55 kg. Scale changes in the breeding values and heritability estimates occurred along the gradients for the two weights; the genetic correlations between breeding value breeding values were also similar for both weights. These correlations were high between the close gradients, and low to even negative between extreme environments. Slopes representing the environmental sensitivity were high, with changes of scale and changes in classification of ten bulls with a great numbers of calves for the two traits. When regression slopes of the ten bulls with the highest breeding value breeding values were evaluated, these values were different in W120 from those in W210, perhaps due to the greater influence of maternal effect on W120. These results characterize the influence of GxE on the pre-weaning weights of animals in the humid tropical regions of Brazil. Due to this, it is possible to get greater precision on the predictions of the animals breeding values breeding value. A less biased selection and a greater genetic progress occurred.

Experimental evidence simultaneously confirms and contests assumptions implicit to otolith microchemistry research

Otolith microchemistry has become an integral fisheries tool, yet the utility of this tool hinges on the assumptions that (i) elements are temporally stable once deposited in the otolith and (ii) the influence of maternal effects are temporally limited. Here we test these assumptions by quantifying through time the chemical signatures from two families of brown trout (Salmo trutta), differing in maternal life history (i.e., mothers were either anadromous or nonanadromous). Concentrations of zinc, strontium, and barium were temporally stable in the core signatures between different aged siblings, but significant differences in the elemental concentrations of magnesium and manganese were detected. The Sr concentration (indicative of maternal influence) on the growing surface of otoliths converged briefly between families at 3–5 weeks post-emergence, but never stabilized during the course of the experiment. Taken together, these results both confirm and call into question assumptions implicit to otolith microchemistry research. To the extent that the patterns observed here are representative across species, caution is warranted when using otolith microchemistry to address certain types of ecological questions in nature.

The influence of maternal effects in larval survival on fishery harvest reference points for two life-history patterns

Increased larval viability with increased spawner age (i.e., maternal effects) have been observed in Atlantic cod (Gadus morhua) and Pacific rockfish (Sebastes spp.) stocks. Analytical results from a Beverton–Holt recruitment model indicate density-independent maternal effects affected the relative stock productivity and fishing rate reference points. We simulated populations based on Pacific cod (Gadus macrocephalus) and Pacific ocean perch (Sebastes alutus) to explore how estimates of reference points Fmsy and Fcrash are affected by maternal effects and potential interactions with life-history pattern, recruitment autocorrelation, and exploitation rate. Estimates of Fmsy and Fcrash were made from populations with maternal effects using either total larvae (proportional to eggs) or viable larvae (incorporating the maternal effect). Maternal effects have the largest impact upon estimated population productivity at high fishing rates. Estimates of Fmsy and Fcrash for cod were also affected by autocorrelated recruitment variability because of their reduced longevity compared with Pacific ocean perch. These results suggest the importance of evaluating the influence of maternal effects on estimated stock productivity on a case-by-case basis, particularly for depleted stocks composed of relatively young spawners.

Yield trait improvement of bay scallops following complete diallel crosses between different scallop stocks

This study describes the complete diallel hybridization between newly introduced bay scallop stock (W) from Canada and local commercial stock (D) grown under laboratory conditions, in China. Larval survival and growth during all life stages (larvae, spat, and adult) were compared among hybrid (DW, WD) and purebred (DD, WW) populations. Significant heterosis was detected for survival during the larval stage (> 1% of the mid-parent values). The mean heterosis (H (m)) varied in growth throughout the life span. More than 50% of the H (m) values were positive and negative in the DW and WD groups, respectively. The influence of maternal effects and mating types (intrapopulation vs. interpopulation crosses) on growth for all life stages was not consistent. Larval survival did not differ significantly (P > 0.05) with maternal effect or mating type. In the harvest stage, shell length (SL), shell height (SH), shell width (SW), and total weight (TW) were larger in the hybrid compared with the inbred groups. Positive H (m) values were observed in SL (1.5%), SW (5.8%), and TW (12.3%), and were more significant in the DW groups (6.1%, 4.5%, 6.8%, and 27.2%). These results suggest that hybridization between two geographic populations is a good tool for improving bay scallop growth. However, unstable heterosis between the two populations requires further study.

Maternal effects on growth and competitive ability in a commonly used restoration species

Maternal effects in production gardens may improve or inhibit the performance of seeds planted in large-scale restoration. In ex situ experiments, we tested seeds of the native grass Poa secunda J. Presl (Poaceae) produced by the same maternal families grown in 3 different production garden environments. We measured progeny performance for 5 variables: germination, emergence, growth, competitive tolerance, and competitive ability. Seed size was correlated with root morphology, with larger seeds producing less root volume. Larger seeds conferred better germination and higher competitive ability only in some progeny growth environments. We found that the production garden affected seed size in some maternal families more than others. Also, other effects of the production garden were uncorrelated with seed size: early plant size, final plant size, and competitive tolerance. Adaptive maternal effects were found for germination in one production environment and for early plant size in another production environment. By understanding the influence of maternal effects under field conditions, we may be able to manipulate production environments to maximize the performance and competitive ability of restoration materials.

Incorporation of weight-specific relative fecundity and maternal effects in larval survival into stock assessments

Marine fish populations may exhibit a number of complexities in their reproductive dynamics, such as weight-specific relative fecundity (i.e. eggs produced per spawner weight increases with spawner size) and maternal effects (i.e. reduced larval survival with reduced spawner age), that are typically not incorporated in stock assessment models. Improved information on reproductive biology could alter estimates of stock productivity and potentially improve estimation of stock–recruitment parameters. In this study, we examined the influence of maternal effects and weight-specific relative fecundity on stock status (defined as reproductive potential and measured as eggs, larvae, or spawning stock biomass), Fmsy, and the statistical fit of stock–recruitment curves estimated within the Bering Sea/Aleutian Islands Pacific ocean perch (Sebastes alutus) and Gulf of Alaska walleye pollock (Theragra chalcogramma) statistical catch-at-age assessment models. In each example, estimates of recruitment strength and the variation around stock–recruitment curves were relatively insensitive to various indices of reproductive potential. However, weight-specific relative fecundity increased estimates of Fmsy, whereas maternal effects decreased estimates of Fmsy. The range of Fmsy estimates obtained for walleye pollock from eight indices of reproductive potential was 0.12–0.19, whereas the Fmsy range for Pacific ocean perch from three indices of reproductive potential was 0.079–0.084. For walleye pollock, weight-specific relative fecundity and recent increases in spawner weight-at-age resulted in an upward trend in reproductive potential relative to constant relative fecundity with spawner size. The two examples demonstrate the influence of reproductive biology upon stock productivity even in cases where residual recruitment variation is relatively unaffected, and motivate the ongoing monitoring of reproductive status and its incorporation in estimation of fishing rate reference points.

The maladaptive significance of maternal effects for plants in anthropogenically modified environments

Maternal effects directly and indirectly modify an offspring’s phenotype during development, preparing the offspring for an environment similar to an environment experienced by the mother. Evolutionarily, this could be adaptive if organisms did not experience a large amount of environmental variation across generations. We argue increased anthropogenic changes have led maternal effects to be maladaptive in plants. Similar problems in humans have been proposed, where metabolic diseases may be increased by a mismatch between the in utero environment and the adult environment; often referred to as the Barker Hypothesis. Plants may experience similar metabolic and functional disorders, caused by maternal effects generated from unreliable environmental cues. In the last 200 years, human activities have increased habitat fragmentation, changed patterns of nutrient deposition, and increased climatic variation within and among years. In this manuscript, we suggest that ecologists should consider the increased negative influence of maternal effects on plant growth and reproduction in spatially fragmented and temporally stochastic landscapes. Several implications for conservation and research arise from this discussion: (1) researchers should focus on evolutionarily relevant measures of spatial and temporal heterogeneity, (2) the maternal history of seeds used for population restoration should be considered, and (3) contiguous habitats should be constructed to reduce the impact of evolutionary traps.

Inheritance of Vertebral Number in the Three-Spined Stickleback (Gasterosteus aculeatus)

Intraspecific variation in the number of vertebrae is taxonomically widespread, and both genetic and environmental factors are known to contribute to this variation. However, the relative importance of genetic versus environmental influences on variation in vertebral number has seldom been investigated with study designs that minimize bias due to non-additive genetic and maternal influences. We used a paternal half-sib design and animal model analysis to estimate heritability and causal components of variance in vertebral number in three-spined sticklebacks (Gasterosteus aculeatus). We found that both the number of vertebrae (h2 = 0.36) and body size (h2 = 0.42) were moderately heritable, whereas the influence of maternal effects was estimated to be negligible. While the number of vertebrae had a positive effect on body size, no evidence for a genetic correlation between body size and vertebral number was detected. However, there was a significant positive environmental correlation between these two traits. Our results support the generalization-in accordance with results from a review of heritability estimates for vertebral number in fish, reptiles and mammals-that the number of vertebrae appears to be moderately to highly heritable in a wide array of species. In the case of the three-spined stickleback, independent evolution of body size and number of vertebrae should be possible given the low genetic correlation between the two traits.

The influence of maternal effects on indirect benefits associated with polyandry

Despite numerous and diverse theoretical models for the indirect benefits of polyandry, empirical support is mixed. One reason for the difficulty in detecting indirect benefits of polyandry may be that these are subtle and are mediated by environmental effects, such as maternal effects. Maternal effects may be especially important if females allocate resources to their offspring depending on the characteristics of their mating partners. We test this hypothesis in the burying beetle Nicrophorus vespilloides, a species that provides extensive and direct parental care to offspring. We used a fully factorial design and mated females to one, two, three, four or five different males and manipulated conditions so that their offspring received reduced (12 h) or full (ca 72 h) maternal care. We found that average offspring fitness increased with full maternal care but there was no significant effect of polyandry or the interaction between the duration of maternal care and the level of polyandry on offspring fitness. Thus, although polyandry could provide a mechanism for biasing paternity towards high quality or compatible males, and variation in parental care matters, we found no evidence that female N. vespilloides gain indirect benefits by using parental care to bias the allocation of resources under different mating conditions.

Parent-Offspring Conflict and Coadaptation

The evolution of family life has traditionally been studied in parallel by behavioral ecologists and quantitative geneticists. The former focus on parent-offspring conflict and whether parents or offspring control provisioning, whereas the latter concentrate on the coadaptation of parental supply and offspring demand. Here we show how prenatal effects on offspring begging can link the two different approaches. Using theoretical and experimental analyses, we show that when offspring control provisioning, prenatal effects primarily serve the parent's interests: Selection on parents drives coadaptation of parent and offspring traits. In contrast, when parents control provisioning, prenatal effects primarily serve the offspring's interests: Selection on the offspring drives coadaptation of parent and offspring traits. Parent-offspring conflict may thus be responsible for the selective forces that generate parent-offspring coadaptation.

Assessing maternal effects on metabolic rate dynamics along early development in brown trout (Salmo trutta): an individual-based approach

Routine metabolic rate (oxygen consumption) of individual eggs and larvae of brown trout (Salmo trutta) originating from different families were monitored from fertilisation to the onset of emergence by means of flow through micro-respirometry. This measuring system revealed an accurate tool to measure oxygen consumption on small organisms at the individual level, and daily consumption proved to be very stable. The mass-specific metabolic rate remained low from fertilisation to hatching, and then increased quickly until the age of emergence. A Bayesian modelling approach was used to adequately infer maternal effects on metabolic rate dynamics all along the development period. Substantial differences were found between families, affecting average metabolic rate as well as intra-family variance. That is, offspring originating from different females may have different energetic needs at emergence from gravel. Moreover, between siblings, variability in metabolic rate is also under the influence of maternal effects. Implications of this metabolic rate variability are discussed with regard to life history strategies and early behaviours.

Evolution of maternal effects: past and present.

It has been said that many original ideas reflect a convergence of related thought that coalesces into a unified representation of what many have been thinking. This is certainly true for the subfield of maternal effects evolution. The study of maternal effects has a long history. The first two