Maternal Environmental Effects Research Articles

Genetic analysis on body weight at different ages in broiler chicken raised in commercial environment.

A multivariate model was developed and used to estimate genetic parameters of body weight (BW) at 1-6weeks of age of broilers raised in a commercial environment. The development of model was based on the predictive ability of breeding values evaluated from a cross-validation procedure that relied on half-sib correlation. The multivariate model accounted for heterogeneous variances between sexes through standardization applied to male and female BWs differently. It was found that the direct additive genetic, permanent environmental maternal and residual variances for BW increased drastically as broilers aged. The drastic increase in variances over weeks of age was mainly due to scaling effects. The ratio of the permanent environmental maternal variance to phenotypic variance decreased gradually with increasing age. Heritability of BW traits ranged from 0.28 to 0.33 at different weeks of age. The direct genetic effects on consecutive weekly BWs had high genetic correlations (0.85-0.99), but the genetic correlations between early and late BWs were low (0.32-0.57). The difference in variance components between sexes increased with increasing age. In conclusion, the permanent environmental maternal effect on broiler chicken BW decreased with increasing age from weeks 1 to 6. Potential bias of the model that considered identical variances for sexes could be reduced when heterogeneous variances between sexes are accounted for in the model.

Intergenerational effects on offspring telomere length: interactions among maternal age, stress exposure and offspring sex.

Offspring produced by older parents often have reduced longevity, termed the Lansing effect. Because adults usually have similar-aged mates, it is difficult to separate effects of maternal and paternal age, and environmental circumstances are also likely to influence offspring outcomes. The mechanisms underlying the Lansing effect are poorly understood. Variation in telomere length and loss, particularly in early life, is linked to longevity in many vertebrates, and therefore changes in offspring telomere dynamics could be very important in this context. We examined the effect of maternal age and environment on offspring telomere length in zebra finches. We kept mothers under either control (ad libitum food) or more challenging (unpredictable food) circumstances and experimentally minimized paternal age and mate choice effects. Irrespective of the maternal environment, there was a substantial negative effect of maternal age on offspring telomere length, evident in longitudinal and cross-sectional comparisons (average of 39% shorter). Furthermore, in young mothers, sons reared by challenged mothers had significantly shorter telomere lengths than sons reared by control mothers. This effect disappeared when the mothers were old, and was absent in daughters. These findings highlight the importance of telomere dynamics as inter-generational mediators of the evolutionary processes determining optimal age-specific reproductive effort and sex allocation.

Direct and transgenerational effects of an experimental heatwave on early life stages in a freshwater snail

Abstract Global climate change imposes a serious threat to natural populations of many species. Estimates of the effects of climate change‐mediated environmental stresses are, however, often based only on their direct effects on organisms, and neglect the potential transgenerational (e.g. maternal) effects. We tested whether high temperature (i.e. an experimental heatwave), which is known to reduce the performance of adult Lymnaea stagnalis snails, affects the produced offspring (eggs and hatchlings) through maternal effects, and how strong these effects are compared with the effects of direct exposure of offspring to high temperature. We examined the effect of maternal thermal environment (15°C versus 25°C) on per offspring investment (egg size), and the role of both maternal and offspring thermal environments (15°C versus 25°C) on hatching success and developmental time of eggs, offspring survival after hatching, and hatchling size at the age of 5 weeks. Exposure of mothers to high temperature reduced the size of oviposited eggs, increased their hatching success, and also made the onset of hatching earlier. However, high maternal temperature reduced the survival and the final size of hatched juveniles. Direct exposure of offspring to high temperature reduced their survival (both eggs and hatchlings) but increased the developmental rate and growth of those individuals that survived. Interestingly, the magnitude of maternal effects on hatching success of eggs and hatchling survival were similar to the direct effects of high temperature. Our results indicate that heatwaves can affect natural populations through transgenerational maternal effects and that the magnitude of those effects can be equally strong to the direct effects of temperature, although this depends on the trait considered. These findings highlight the importance of considering the transgenerational effects of climate warming when estimating its effects in the wild.

Effect of maternal environment on yolk immunoreactive corticosterone and its influence on adrenocortical and behavioral activity in chicks of Greater Rhea (Rhea americana)

Maternal corticosterone in avian eggs may modify offspring phenotype in order to increase survival in poor environments. In the Greater Rhea (Rhea americana), we previously found that yolk immunoreactive corticosterone is influenced by the quality of the maternal environment: eggs laid by females of the intensive rearing system (IRS), living in poor captive conditions, had higher yolk immunoreactive corticosterone than those produced by females of the semi-extensive rearing system (SRS), living in better conditions. Here, we evaluate if these different hormone levels are associated with the production of different phenotypes. We collected eggs from the IRS and SRS for hormonal quantification and artificial incubation. Then, half of the chicks selected from each environment were exposed to a capture and restraint protocol, and the rest remained undisturbed and were used as controls. In the IRS, we found that higher yolk immunoreactive corticosterone was associated with the production of chicks that had reduced hatchability, lower hatchling mass and higher baseline fecal glucocorticoid metabolites (FGM) than those produced by SRS females. Moreover, after capture and restraint, IRS chicks did not modify their FGM nor their behaviors compared to their controls, while SRS chicks increased their FGM and spent more time ambulating and less time pecking, compared to their controls. These results indicate that yolk immunoreactive corticosterone could modify offspring phenotype. Although future studies are needed to elucidate their implications for fitness, our results suggest that yolk corticosterone could be mediating an adaptive maternal effect that allows individuals to better cope with poor conditions.

Association of Genetic and Environmental Factors With Autism in a 5-Country Cohort

The origins and development of autism spectrum disorder (ASD) remain unresolved. No individual-level study has provided estimates of additive genetic, maternal, and environmental effects in ASD across several countries. To estimate the additive genetic, maternal, and environmental effects in ASD. Population-based, multinational cohort study including full birth cohorts of children from Denmark, Finland, Sweden, Israel, and Western Australia born between January 1, 1998, and December 31, 2011, and followed up to age 16 years. Data were analyzed from September 23, 2016 through February 4, 2018. Across 5 countries, models were fitted to estimate variance components describing the total variance in risk for ASD occurrence owing to additive genetics, maternal, and shared and nonshared environmental effects. The analytic sample included 2 001 631 individuals, of whom 1 027 546 (51.3%) were male. Among the entire sample, 22 156 were diagnosed with ASD. The median (95% CI) ASD heritability was 80.8% (73.2%-85.5%) for country-specific point estimates, ranging from 50.9% (25.1%-75.6%) (Finland) to 86.8% (69.8%-100.0%) (Israel). For the Nordic countries combined, heritability estimates ranged from 81.2% (73.9%-85.3%) to 82.7% (79.1%-86.0%). Maternal effect was estimated to range from 0.4% to 1.6%. Estimates of genetic, maternal, and environmental effects for autistic disorder were similar with ASD. Based on population data from 5 countries, the heritability of ASD was estimated to be approximately 80%, indicating that the variation in ASD occurrence in the population is mostly owing to inherited genetic influences, with no support for contribution from maternal effects. The results suggest possible modest differences in the sources of ASD risk between countries.

Heritabilities, social environment effects and genetic correlations of social behaviours in a cooperatively breeding vertebrate.

Social animals interact frequently with conspecifics, and their behaviour is influenced by social context, environmental cues and the behaviours of interaction partners, allowing for adaptive, flexible adjustments to social encounters. This flexibility can be limited by part of the behavioural variation being genetically determined. Furthermore, behaviours can be genetically correlated, potentially constraining independent evolution. Understanding social behaviour thus requires carefully disentangling genetic, environmental, maternal and social sources of variations as well as the correlation structure between behaviours. Here, we assessed heritability, maternal, common environment and social effects of eight social behaviours in Neolamprologus pulcher, a cooperatively breeding cichlid. We bred wild-caught fish in a paternal half-sibling design and scored ability to defend a resource against conspecifics, to integrate into a group and the propensity to help defending the group territory ("helping behaviour"). We assessed genetic, social and phenotypic correlations within clusters of behaviours predicted to be functionally related, namely "competition," "aggression," "aggression-sociability," "integration" and "integration-help." Helping behaviour and two affiliative behaviours were heritable, whereas there was little evidence for a genetic basis in all other traits. Phenotypic social effects explained part of the variation in a sociable and a submissive behaviour, but there were no maternal or common environment effects. Genetic and phenotypic correlation within clusters was mostly positive. A group's social environment influenced covariances of social behaviours. Genetic correlations were similar in magnitude but usually exceeding the phenotypic ones, indicating that conclusions about the evolution of social behaviours in this species could be provisionally drawn from phenotypic data in cases where data for genetic analyses are unobtainable.

Domestic-wild hybridization to improve aquaculture performance in Chinook salmon

Salmon farming is one of Canada's fastest growing industries and contributes to Canada's economy as well as creating jobs in rural areas; however, the industry is challenged by the need to balance production economics against environmental impacts. While Atlantic salmon (Salmo salar) are the most commonly farmed species on the west coast of Canada, Chinook salmon (Oncorhynchus tshawytscha) are a valuable alternative, as they fill a niche market and generate reduced environmental concerns because they are a native species. However, Chinook salmon have not been systematically domesticated, and their performance remains highly variable. Here we report on the results of a research program designed to develop a performance-enhanced hybrid Chinook salmon stock. Growth and survival were estimated for seven domestic-wild hybrid Chinook salmon crosses at various freshwater stages and during 15 months of saltwater rearing at a British Columbia Chinook salmon farm and compared with domestic-domestic crosses (control). The project included 8640 individually (PIT) tagged offspring from the domestic stock and seven domestic-wild hybrid stocks originating from the Lower Fraser Valley, Lower Mainland Vancouver, and Vancouver Island, British Columbia, Canada. Within each stock, milt from 10 sires was used to fertilize eggs pooled from 15 highly inbred domestic females to produce 80 half-sib families. Our breeding design allows the partitioning of stock and sire effects, and minimises maternal genetic and maternal environment effects. Replicates of all families were reared under common environmental conditions in both fresh- and salt water and monitored for body size and survival. There was significant variation in survival, body size, and saltwater biomass among the Chinook salmon hybrid stocks. The performance of some of the hybrid crosses exceeded that of the fully domesticated stock, although the pattern of performance varied with rearing stage. Overall, two hybrid stocks consistently outperformed the domestic stock in terms of survival, growth, and biomass estimates. We systematically assess production performance across a wide range of wild-domestic hybrid crosses in a Pacific salmon species, and our results highlight opportunities to improve the production performance of Chinook salmon culture.

Causes and consequences of the variation in the number of ovarian follicles in cattle

Summary. In cattle we have noted that the antral follicle count (AFC, follicles ≥3 mm in diameter) varies greatly among animals (from 5 to 50), is repeatable within animals, and is highly correlated with the total number of healthy follicles in ovaries. Also, animals with low AFC have higher serum concentrations of FSH and LH, but lower concentrations of Anti-Mullerian Hormone, progesterone and androgens than animals with high AFC. We have investigated the effect of maternal environment during gestation on their offspring AFC by restricting maternal nutrition to 60% of maintenance requirements (compared with 100% in controls) during the first third of gestation. Calves born to nutritionally restricted mothers had 60% lower AFC compared with calves born to mothers fed control diets. In other studies we have evidence to indicate that fertility may be compromised in animals with low AFC due to effects on oocytes, progesterone and the endometrium compared with animals with high AFC. To examine this directly we assessed AFC in post-partum dairy cows and found that cows with a high AFC had higher pregnancy rates, shorter calving to conception intervals and received fewer services during the breeding season compared with cows with a low AFC. In addition, the high variation in follicle numbers in adults may not only be reflective of reproductive disorders and suboptimal fertility, but there is evidence to indicate that it may be associated with alterations in the function of other non-reproductive systems (e.g. cardiovascular) that may have profound effects on the animal's health and welfare.

Estimation of direct and maternal (co)variance components for lactation traits in Jersey crossbred cattle at an organized farm

Genetic parameters and (co)variance components were estimated for 305 days milk yield (305DMY), total milk yield (TMY), lactation length (LL) and peak yield (PY) in an organized herd of Jersey crossbred cattle. Restricted maximum likelihood (REML) fitting an animal model and ignoring or including maternal genetic or permanent environmental effects was used for carrying out analyses. Six different animal models were fitted for all traits. The best model was chosen after testing the improvement of log-likelihood values. Direct heritability estimates were 0.55, 0.50, 0.25 and 0.41 for 305DMY, TMY, LL and PY, respectively. Maternal genetic effects contributed 9 and 17% of the total variance for 305DMY and PY, respectively. Results suggest that maternal additive effect was important for 305 days milk yield and peak yield whereas permanent environmental maternal effects did not contribute to the total phenotypic variance of the considered traits in our study. Moderate to high direct heritability estimates varying from 0.25 to 0.55 for all considered lactation traits in this study suggests that there is adequate scope of improvement for these traits through selection under the prevailing management conditions. Further, for 305 days milk yield and peak yield maternal heritability was found to be imperative indicating that for improving these traits through selection both direct additive as well as maternal genetic effect must be taken into consideration.

Offspring of aged mothers of rotifer Brachionus calyciflorus shows lower sexual propensity than their elder siblings under crowded conditions

Maternal effects are one of the most interesting topics in evolutionary ecology as they can affect the rate of evolution and population dynamics by phenotypic manipulation of offspring related to fitness. At present, studies examining the interaction between maternal environment effects and maternal age (birth order) effects are scarce. We designed an experiment to reveal whether environmentally induced maternal manipulation works equally on offspring across birth orders in rotifer Brachionus calyciflorus. In the experiment, newborn amictic mothers (F0) were cultured parallelly in low (LD) and high (HD) population density. Offspring (F1) of young (YF0) and old (OF0) mothers in both LD and HD groups were cultured under a crowded condition and the mixis ratios of both F1 and F2 were examined. Results show that F1 from HD-YF0 had a significantly higher mixis ratio and those amictic ones produced daughters (F2) with higher mixis ratio in response to crowding than those from HD-OF0. In contrast, no such differences among F1 siblings were found in the LD-F0 group. Therefore, the effect of maternal age on the sexual propensity of the offspring can be affected independently by the maternal population density.

How much influence does the paternal parent have on seed germination?

AbstractIt is well documented that the mother plant has much more influence than the father on seed dormancy/germination, especially of the F1offspring, primarily by providing all material (maternally derived tissue) to the diaspore coat(s); by maternal environmental effects and provisioning of nutrient resources, mRNA transcripts, protein, the hormone abscisic acid and nitrate to the seed during its development; and by determining progeny environment via dispersal and phenology. There is some evidence that the paternal influence on seed dormancy/germination of the offspring (seeds) can be mediated through multiple paternity (including mate number and diversity), non-nuclear (cytoplasmic) and nuclear (genotypic) inheritance and paternal environmental effects. Our primary aim was to determine via a literature review the influence (or not) of the paternal parent on seed germination. Altogether, 37 of 59 studies (62.7%) indicated a positive influence of the father on seed germination, although not all of them were statistically significant. In general, however, results of studies reported in the literature do not offer strong support for the paternal parent having a major role in seed germination (or seed size) of his F1offspring.

UTILIZAÇÃO DE MODELOS DE REGRESSÃO ALEATÓRIA PARA OBTENÇÃO DE PARÂMETROS GENÉTICOS DE BOVINOS DA RAÇA TABAPUÃ

Resumo Este trabalho utilizou 28.643 registros de pesos, do nascimento aos 660 dias de idade, de 6.471 animais da raça Tabapuã para estimar componentes de variância, covariância e parâmetros genéticos, utilizando o modelo de regressão aleatória. Foi utilizado algoritmo de busca AIREML através do método da máxima verossimilhança restrita pelo programa computacional DFREML. Os modelos incluíram: como aleatórios, os efeitos genético aditivo direto, materno, de ambiente permanente de animal e materno; como fixos, os efeitos de grupo de contemporâneos; como covariáveis, a idade do animal à pesagem e a idade da vaca ao parto. As estimativas de variância genética aditiva direta obtidas aumentaram com a idade. As estimativas de herdabilidade para o efeito aditivo direto mostram o decréscimo da herdabilidade do nascimento até a desmama, enquanto as estimativas de herdabilidade materna apresentaram aumento do nascimento até a desmama, decrescendo nas idades seguintes. As correlações genéticas diretas variaram de moderadas a altas, diminuindo suas magnitudes à medida que aumentou a distância entre as idades dos animais. O modelo de regressão aleatória utilizado mostrou-se adequado para descrever as mudanças nas variâncias dos pesos de bovinos da raça Tabapuã do estado da Bahia.

Maternal diet and age alter direct and indirect relationships between life‐history traits across multiple generations

Abstract Maternal age has important consequences for offspring fitness, with influences on size, development and reproductive schedules. Such maternal age effects may be driven by differential provisioning of resources; yet, little is known about the role of environmental supply of nutritional resources in mediating such effects. We tested the influence of limiting nutritional resource, dietary phosphorus (P), on maternal age effects across multiple generations by examining the potential interactive effects of maternal nutrition and age on daughter and granddaughter life‐history traits in the freshwater crustacean Daphnia pulicaria. Maternal age and diet had significant but contrasting effects on offspring life history. We did not observe any evidence that age effects on offspring life history are mediated by maternal diet. However, granddaughter growth and size at maturation were influenced by the interaction between grandmaternal age and diet, suggesting that the appearance of transgenerational effects of age and diet were delayed by one generation. Because offspring life history is often linked directly and/or indirectly to life history variation in previous generations, we utilized structural equation modelling (SEM) to assess such direct or indirect relationships. SEM revealed striking differences in the relationship between growth, development time and fecundity both within and among generations, depending on the age and diet in the F0 generation. Interestingly, direct and persistent relationships between the F0 generation and the F2 generation are most prevalent when grandmothers are old and fed low P diets, and such relationships are largely driven by fecundity in the F0 generation. Additionally, indirect causal relationships between the F0 generation and F2 generation are most pronounced when grandmothers are young and fed low P diets or when grandmothers are old and fed high P diets. Our results indicate that transgenerational effects of maternal age and environment persist across multiple generations, and vary between successive generations. Further, our examination of the interaction network between life‐history traits of each generation suggest that the mechanisms for such persistent transgenerational effects are highly dependent on maternal condition. A plain language summary is available for this article.

Active and passive maternal smoking during pregnancy and risk of having a child with polydactyly: a case-control study

Objective: The number of children with polydactyly is increasing. In addition to genetic factors, an influence of maternal behavior or environmental effects during pregnancy is becoming increasingly apparent. However, epidemiological data on these effects are lacking. Methods: This hospital-based, case-control study enrolled 143 infants with polydactyly and 286 controls without genetic diseases to evaluate the association between active and passive maternal smoking during pregnancy and the likelihood of giving birth to a child with polydactyly. Results: Active and passive maternal smoking during pregnancy was associated with an increased risk of giving birth to a child with polydactyly (active smoking: OR=4.74, 95%CI: 1.43-15.65, P=0.011; passive smoking: OR=2.42, 95%CI: 1.32-4.44, P=0.004). After adjusting for confounders, smoking during pregnancy remained significant influence on polydactyly (active smoking: aOR=7.27, 95%CI: 1.72-30.72, P=0.007; passive smoking: aOR=2.41, 95%CI: 1.11-5.23, P=0.026). Conclusion: Active and passive maternal smoking during pregnancy appears to be a risk factor for polydactyly in newborns.

Maternal environment regulates morphological and physiological traits in Eucalyptus grandis

The phenotype of a plant can be shaped by the biotic and abiotic conditions to which their parents are subjected. This phenotypic plasticity known as maternal environmental effect occurs regardless of the changes in the DNA sequences. Whereas the effect of the maternal environment on plant phenotype has been studied, its specific influence on plant physiology is less clear. This study considered the influence of the maternal environment on the regulation of plant morphology and physiology in progeny of Eucalyptus grandis. Plants were grown from seeds collected from two E. grandis clonal seed orchards that differed in environmental conditions (e.g. precipitation). Plant relative growth rate (RGR), leaf gas exchange and water use efficiency (WUE) were measured in the seedlings. RGR was 10% higher in the offspring from the maternal environment receiving higher precipitation levels. Leaf gas exchange, specifically leaves intercellular CO2, and intrinsic WUE were also influenced by maternal environments. Intrinsic WUE was significantly lower in the orchard that received lower precipitation levels. The results demonstrate that the maternal environment can regulate the physiology of E. grandis in the subsequent generation. These analyses are useful to optimise tree improvement in a changing environment. Moreover, in a scenario of climate change, maternal environmental effects may be a crucial mechanism for certain species to get acclimated to sudden changes in environmental conditions.

Impact of prenatal and postnatal maternal environment on nephron endowment, renal function and blood pressure in the Lewis polycystic kidney rat.

Maternal insufficiency during fetal development can have long-lasting effects on the offspring, most notably on nephron endowment. In polycystic kidney disease (PKD), variability in severity of disease is observed and maternal environment may be a modifying factor. In this study, we first established that in a rodent model of PKD, the Lewis polycystic kidney (LPK) rat's nephron numbers are 25% lower compared with wildtype animals. We then investigated the effects of prenatal and postnatal maternal environment on phenotype and nephron number. LPK pups born from and raised by homozygous LPK dams (control) were compared with LPK pups cross-fostered onto heterozygous LPK dams to improve postnatal environment; with LPK pups born from and raised by heterozygous LPK dams to improve both prenatal and postnatal environment and with LPK pups born from and raised by Wistar Kyoto-LPK heterozygous dams to improve both prenatal and postnatal environment on a different genetic background. Improvement in both prenatal and postnatal environment improved postnatal growth, renal function and reduced blood pressure, most notably in animals with different genetic background. Animals with improved postnatal environment only showed improved growth and blood pressure, but to a lesser extent. All intervention groups showed increased nephron number compared with control LPK. In summary, prenatal and postnatal environment had significant effect in delaying progression and reducing severity of PKD, including nephron endowment.

Maternal Environment Effect of Warming and Eutrophication on the Emergence of Curled Pondweed, Potamogeton crispus L.

Maternal effects may play an important role in life history and offspring performance of aquatic plants. Performance and response of maternal and offspring aquatic plants can affect population dynamics and community composition. Understanding maternal effect can help to fill a gap in the knowledge of aquatic plant life cycles, and provide important insights for species’ responses to climate change and eutrophication. This study showed that maternal warming and eutrophication significantly affected the early life stages of curled pondweed, Potamogeton crispus, a submerged macrophyte. Propagule in warmed condition had higher germination percentages and a shorter mean germination time than those under ambient conditions. However, propagule germination in phosphorus addition treatment was inhibited due to the negative effect of eutrophication, e.g., phytoplankton competition and deteriorated underwater light. Meanwhile, elevated temperature led to a decrease of total nitrogen concentrations and an increase of carbon: nitrogen ratios in plant tissues, which may suggest that P. crispus will allocate more nutrients to propagules in order to resist the adverse effects of high temperature. A subsequent germination experiment in the same ambient condition showed that maternal warming promoted seedling emergence in contrast to maternal phosphorus addition. Consequently, global warming could modify population growth via maternal environmental effects on early life histories, while increased anthropogenic nutrient inputs may result in a decreased submerged macrophyte. These maternal effects on offspring performance may change competition and the survival of early life-history stages under climate warming and eutrophication through changing the ecological stoichiometry of plant tissue.

Transgenerational effect of maternal growth environment on flowering date in rice (Oryza sativa L.)

Flowering date reflects the adjustment of a plant’s growth period to a given environment. This is true of rice, which is a major food source around the world. We tested whether rice plants can recognize and record natural variation in their growth environments and thus control flowering in their progeny. We grew seedlings of two japonica cultivars from the same seed stock at two locations, in cool and warm climates, in Japan until they produced seeds. We then tested their progeny at the same locations. The progeny of mother plants of both cultivars grown in a cool climate flowered significantly earlier (by 1 to 6 days) than the progeny of mother plants grown in a warm climate. This transgenerational effect was partially explained by water temperatures during the vegetative growth stage. This is the first study to show the effect of transgenerational effect of natural environments on flowering date in rice.

Impact of additive direct and maternal heritability on production efficiency traits in Jersey crossbred cattle

Variance components, direct and maternal heritability were estimated for milk production efficiency traits namely, milk yield per day of lactation length (MY/LL) and milk yield per day of calving interval (MY/CI) in Jersey crossbreds maintained at Eastern Regional Station of ICAR-National Dairy Research Institute, West Bengal (India). Data analyses were done using restricted maximum likelihood (REML) method with six alternative animal models (direct and including or excluding maternal associated effects). The best model was chosen after testing the improvement of the log-likelihood values and it revealed direct heritability estimates as 0.47 and 0.25 for MY/LL and MY/CI traits, respectively. Maternal heritability (0.14) was found to be important for MY/LL trait and permanent environmental maternal effect contributed 12% to the total phenotypic variance of the MY/CI. Direct heritability estimates were high (0.47) for MY/LL and moderate for MY/CI (0.25) trait suggesting that there is ample scope of improvement through selection for milk production efficiency traits in Jersey crossbred maintained at organizedherds.

Association of MSTN gene polymorphism (C354T) with performance traits in raccoon dogs

The aim of the study was to identify polymorphisms within nuclear DNA genes and determine their association with the performance traits of farmed raccoon dogs. The study involved 354 animals and their breeding documentation data. Myostatin (MSTN), insulin-like growth factor 1 (IGF1), and growth hormone (GHR) genes were amplified, sequenced, and subjected to bioinformatics and statistical analysis. Estimation of variance components was performed with the residual maximum likelihood (REML) method, and best linear unbiased prediction (BLUP) of the breeding values was carried out. The predictors of the traits of direct additive, maternal additive, and random-specific maternal environmental effects were analysed. Within the nucleotide sequences of the analysed genes, one silent single nucleotide polymorphism (SNP) was identified in exon 1 of the MSTN gene. The analysis of the variance of the fixed-specific maternal environmental effect revealed statistically significant differences in the body weight among raccoon dogs with alternative polymorphisms. The mean effects of the estimators of polymorphism addition and dominance measured by MSTN gene regression had mostly a significant impact on the level of the traits estimated in animals. There was statistically significant association of the polymorphism in the MSTN gene with the body weight in raccoon dogs, which validates selection thereof as a candidate gene for this economically most important performance trait of raccoon dogs.