F1 Animals Research Articles

Desempeño y viabilidad económica de novillos semiestabulados a pasto en el Pantanal

The objective of this study was to evaluate the performance of two genetic groups of F1 steers Angus vs. Nellore and Nellore in pasture supplementation and their economic viability. The experiment was conducted at the São Geraldo farm located in the municipality of Bonito – MS, Brazil. It was used 94 steers, being distributed in randomized blocks, totaling two treatments. Treatment 1 – 50 Angus vs. Nellore F1 steers weight 459.32, Treatment 2 – 44 Nellore steers with average weight of 454.45 kg. Performance analysis of the animals was significant (P < 0.05), between the genetic groups of final weight gain, total average weight gain, average daily weight gain and carcass dressing. The F1 animals had the higher total weight gain with 125 kg and the Nellore with 120 kg, representing a gain of 5 kg higher. The daily average weight gain for F1 crossing was 1.53 kg and Nellore presented 1.28 kg, observing a performance of 22.3% higher than F1 in relation to Nellore. The economic analysis showed a treatment effect (P < 0.05) for operating costs (CO), total operating revenue (ROT), cost of capital (CK), gross margin, net margin, economic break-even point, margin Per kg live weight. The profitability of F1 animals with 14.7% and a profitability of 17.6%; while the Nellore animals were with 2.0% lower profitability and a profitability of 14.9%. It was concluded that the cross between Nellore and Angus animals with supplementation obtained greater performance of weight and profitability

Molecular evidence of offspring liver dysfunction after maternal exposure to zinc oxide nanoparticles

Recently, reproductive, embryonic and developmental toxicity have been considered as one important sector of nanoparticle (NP) toxicology, with some studies already suggesting varying levels of toxicity and possible transgenerational toxic effects. Even though many studies have investigated the toxic effects of zinc oxide nanoparticles (ZnO NPs), little is known of their impact on overall reproductive outcome and transgenerational effects. Previously we found ZnO NPs caused liver dysfunction in lipid synthesis. This investigation, for the first time, explored the liver dysfunction at the molecular level of gene and protein expression in offspring after maternal exposure to ZnO NPs. Three pathways were investigated: lipid synthesis, growth related factors and cell toxic biomarkers/apoptosis at 5 different time points from embryonic day-18 to postnatal day-20. It was found that the expression of 15, 16, and 16 genes in lipid synthesis, growth related factors and cell toxic biomarkers/apoptosis signalling pathway respectively in F1 animal liver were altered by ZnO NPs compared to ZnSO4. The proteins in these signalling pathways (five in each pathways analyzed) in F1 animal liver were also changed by ZnO NPs compared to ZnSO4. The results suggest that ZnO NPs caused maternal liver defects can also be detected in offspring that might result in problems on offspring liver development, mainly on lipid synthesis, growth, and lesions or apoptosis. Along with others, this study suggests that ZnO NPs may pose reproductive, embryonic and developmental toxicity; therefore, precautions should be taken with regard to human exposure during daily life.

A link between thrifty phenotype and maternal care across two generations of intercrossed mice.

Maternal effects are causal influences from mother to offspring beyond genetic information, and have lifelong consequences for multiple traits. Previously, we reported that mice whose mothers did not nurse properly had low birth weight followed by rapid fat accumulation and disturbed development of some organs. That pattern resembles metabolic syndromes known collectively as the thrifty phenotype, which is believed to be an adaptation to a stressful environment which prepares offspring for reduced nutrient supply. The potential link between maternal care, stress reactivity, and the thrifty phenotype, however, has been poorly explored in the human and animal literature: only a couple of studies even mention (much less, test) these concepts under a cohesive framework. Here, we explored this link using mice of the parental inbred strains SM/J and LG/J–who differ dramatically in their maternal care–and the intercrossed generations F1 and F2. We measured individual differences in 15 phenotypes and used structural equation modeling to test our hypotheses. We found a remarkable relationship between thrifty phenotype and lower quality of maternal behaviors, including nest building, pup retrieval, grooming/licking, and nursing. To our knowledge, this is the first study to show, in any mammal, a clear connection between the natural variation in thrifty phenotype and maternal care. Both traits in the mother also had a substantial effect on survival rate in the F3 offspring. To our surprise, however, stress reactivity seemed to play no role in our models. Furthermore, the strain of maternal grandmother, but not of paternal grandmother, affected the variation of maternal care in F2 mice, and this effect was mediated by thrifty phenotype in F2. Since F1 animals were all genetically identical, this finding suggests that maternal effects pass down both maternal care and thrifty phenotype in these mice across generations via epigenetic transmission.

Prenatal and Postnatal Assessment in Rabbits with Evacetrapib: A Cholesteryl Ester Transfer Protein Inhibitor.

Evacetrapib, a potent and selective inhibitor of cholesteryl ester transfer protein (CETP), was under development for the treatment of cardiovascular (CV) disease. The purpose of this pre-postnatal study in rabbits was to evaluate the effects of evacetrapib on pregnancy, parturition, and lactation of the maternal animals and on the growth, viability, development, and reproductive performance of the first filial (F1) offspring. The rabbit is considered a relevant species for toxicity testing with evacetrapib as it demonstrates significant CETP expression, whereas mice and rats do not express significant levels of CETP. Evacetrapib was administered daily by oral gavage from gestation day (GD) 7 through lactation day (LD) 41 at dose levels of 0, 10, 30, and 100 mg/kg/day. There were no adverse effects on maternal survival, clinical signs, gestation length, parturition, and litter size. There were no effects on F1 clinical observations, body weight, sexual maturation, conditioned eye blink, functional observational battery, or pathology findings. Treatment-related decreases in F1 postnatal survival and equivocal reductions in F1 mating, fertility, and copulation/conception indices without changes in sperm parameters or pathology of reproductive organs were noted in F1 animals. The maternal no observed adverse effect level (NOAEL) after evacetrapib administration in female rabbits was 100 mg/kg/day. Based on the decreased F1 postnatal survival and equivocal changes in F1 fertility, the NOAEL for F1 neonatal developmental was 30 mg/kg/day. Birth Defects Research 109:486-496, 2017.© 2017 Wiley Periodicals, Inc.

Dynamics of reaching imago stage by F1 animals after terahertz irradiation of parental Drosophila

Terahertz radiation (0.1–10 THz) is increasingly becoming a factor of human habitat. The study of the consequences of radiation allows one to estimate its possible biological danger. Our data indicate that the terahertz irradiation of parental Drosophila shortens the period of embryonic development of their first generation descendants. Significant deviations of data from the control were found, when both females and males were experimental parents. The highest portion of animals with accelerated hatching as compared with the control was found in progenies from irradiated females. The shift of maximal hatching peak to an earlier period was found in descendants of both sexes. Thus, it was for the first time found on the model object (Drosophila) that the terahertz irradiation of parents can have positive or negative consequences in the first generation descendants.

A Mutation of the Prdm9 Mouse Hybrid Sterility Gene Carried by a Transgene

PRDM9 is a protein with histone-3-methyltransferase activity, which specifies the sites of meiotic recombination in mammals. Deficiency of the Prdm9 gene in the laboratory mouse results in complete arrest of the meiotic prophase of both sexes. Moreover, the combination of certain PRDM9 alleles from different mouse subspecies causes hybrid sterility, e.g., the male-specific meiotic arrest found in the (PWD/Ph × C57BL/6J)F1 animals. The fertility of all these mice can be rescued using a Prdm9-containing transgene. Here we characterized a transgene made from the clone RP24-346I22 that was expected to encompass the entire Prdm9 gene. Both (PWD/Ph × C57BL/6J)F1 intersubspecific hybrid males and Prdm9-deficient laboratory mice of both sexes carrying this transgene remained sterile, suggesting that Prdm9 inactivation occurred in the Tg(RP24-346I22) transgenics. Indeed, comparative qRT-PCR analysis of testicular RNAs from transgene-positive versus negative animals revealed similar expression levels of Prdm9 mRNAs from the exons encoding the C-terminal part of the protein but elevated expression from the regions coding for the N-terminus of PRDM9, indicating that the transgenic carries a new null Prdm9 allele. Two naturally occurring alternative Prdm9 mRNA isoforms were overexpressed in Tg(RP24-346I22), one formed via splicing to a 3’-terminal exon consisting of short interspersed element B2 and one isoform including an alternative internal exon of 28 base pairs. However, the overexpression of these alternative transcripts was apparently insufficient for Prdm9 function or for increasing the fertility of the hybrid males.

Transgenic Zebrafish Expressing the Human TEL-AML1 Oncogene Have Aberrant Developmental Myelopoiesis

The t(12;21)(p13;q22) chromosomal translocation resulting in the TEL-AML1 fusion gene is the most common translocation in childhood B cell precursor acute lymphoblastic leukemia (BCP-ALL) and is found in approximately 25% of cases. The translocation arises in utero, and can be found in approximately 1% of newborn infants. However, less than 1% of these children develop leukaemia and this translocation is not observed in adult ALL. This suggests that the cell of origin resulting in the eventual transformation to BCP-ALL is present and disrupted early during development but does not represent a potent oncoprotein. Further evidence for this is provided by animal models show that TEL-AML1 alone is necessary but not sufficient to trigger overt ALL.To further delineate the effects of TEL-AML1 during developmental haematopoiesis we utilized a zebrafish model, Tg(ZβA:hTEL-AML1-EGFP), that expresses human TEL-AML1 (hTEL-AML1) under the control of zebrafish β-actin gene promoter. Previous studies have shown that approximately 2% of these fish develop B-cell leukemia with a long latency.Primitive erythropoiesis was studied using whole mount in situ hybridisation (WISH) in Tg(ZβA:EGFP-hTEL-AML1+/-) and siblings. The expression pattern of ikarosand gata1a showed that primitive erythroid cells develop normally in Tg(ZβA:EGFP-hTEL-AML1+/-). The development of erythroid cells at later stages was studied using o-dianisidine staining, to assess the haemoglobinization of erythrocytes. Our results suggest normal differentiation of erythroblasts into erythrocytes in Tg(ZβA:EGFP-hTEL-AML1+/-) embryos and normal haemoglobinization of erythrocytes.We next examined myelopoiesis in Tg(ZβA:EGFP-hTEL-AML1)using WISH for cebpα and lcp1, and Sudan Black (SB) staining to label mature granulocytes. Primitive myelopoiesis was unperturbed by hTEL-AML1 at 18hpf, however we observed an increased number of SB positive cells commencing at 2 days post fertilization (dpf). SB positive cells continued to increase in number until 4dpf when the difference became less pronounced and was gone by 7dpf (Figure 1). SB positive myeloid cells at these stages are most likely to be derived from the earliest definitive hematopoietic precursors, such as the transient bi-potent erythro-myeloid progenitor (EMP) because primitive myeloid cells are predominantly macrophage-like cells that do not express SB. By 4dpf when definitive hematopoietic stem and progenitor cell (HSPC) derived myelopoiesis is dominant, the observed difference in mature myeloid cell numbers has resolved.The earliest lymphoid cells in zebrafish embryos are thymocytes. Thymocytes were visualized using WISH for gata3 (GATA binding protein 3), lck (T-cell specific tyrosine kinase) and rag1 (recombination activating gene 1). Expression of all three markers was unpertubed indicating that early T cell development is not affected by hTEL-AML1 fusion protein expression.B lymphoid cells have not been convincingly observed in zebrafish until 3 weeks post fertilization despite evidence of VDJ rearrangements in whole embryos from 4dpf. We attempted to identify evidence of B lymphoid cells using WISH for pax5 and cd79b, however we were not able to identify any cells before 10dpf. This supports the observation that B cells do not arise until later in development, or are too low in expression level or few in number to identify by WISH.In order to more closely recapitulate aspects of TEL-AML1 leukemia in humans, where one the remaining endogenouscopy of TEL is frequently lost at diagnosis of BCP-ALL, we have generated a knockout of zebrafish etv6 using CRISPR/Cas9. 4 Etv6 guides targeting zebrafish etv6 were more than 90% efficient at cleaving their DNA target. F0 animals with this mutational burden survived to adulthood with no increase in mortality. By contrast F0 Tg(ZβA:EGFP-hTEL-AML1+/-) injected with etv6 crispr had an increased mortality and showed a variety of developmental abnormalities. Assessment of their haematopoietic compartment is ongoing.In summary we show that early myelopoiesis is disrupted during development in a zebrafish transgenic model expressing human TELAML1, and that this occurs prior to the stage at which definitive pluripotent HSPC-derived myelopoiesis is dominant. This supports the hypothesis that effects of TELAML1 during developmental haematopoiesis underpin its oncogenic potential during childhood. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Transgenerational attenuation of opioid self-administration as a consequence of adolescent morphine exposure

The United States is in the midst of an opiate epidemic, with abuse of prescription and illegal opioids increasing steadily over the past decade. While it is clear that there is a genetic component to opioid addiction, there is a significant portion of heritability that cannot be explained by genetics alone. The current study was designed to test the hypothesis that maternal exposure to opioids prior to pregnancy alters abuse liability in subsequent generations. Female adolescent Sprague Dawley rats were administered morphine at increasing doses (5–25 mg/kg, s.c.) or saline for 10 days (P30-39). During adulthood, animals were bred with drug-naïve colony males. Male and female adult offspring (F1 animals) were tested for morphine self-administration acquisition, progressive ratio, extinction, and reinstatement at three doses of morphine (0.25, 0.75, 1.25 mg/kg/infusion). Grandoffspring (F2 animals, from the maternal line) were also examined. Additionally, gene expression changes within the nucleus accumbens were examined with RNA deep sequencing (PacBio) and qPCR. There were dose- and sex-dependent effects on all phases of the self-administration paradigm that indicate decreased morphine reinforcement and attenuated relapse-like behavior. Additionally, genes related to synaptic plasticity, as well as myelin basic protein (MBP), were dysregulated. Some, but not all, effects persisted into the subsequent (F2) generation. The results demonstrate that even limited opioid exposure during adolescence can have lasting effects across multiple generations, which has implications for mechanisms of the transmission of drug abuse liability in humans.

A two-generation inhalation reproductive toxicity study upon the exposure to manganese chloride

A number of published studies have suggested that high levels of exposure to manganese, especially those found in occupational settings, can adversely affect the reproductive system. The objective of this study was therefore to investigate if these findings can be replicated using the Sprague Dawley rat and, if so, to identify those parts of the reproductive system are more susceptible.Male and female rats were exposed to manganese dichloride (MnCl2) via inhalation at concentrations of 0 (air-control); 5, 10 and 20μg/L air over 10 weeks (F0) and over 11 weeks (F1) prior to mating, and then throughout mating, gestation and lactation until termination after the F1 and F2 generation had reached Day 21 of lactation respectively.Animals were monitored for clinical signs of toxicity and for effects on body weight, food consumption, effects on the entire reproductive system including maternal care. The offspring were monitored for survival and growth up to weaning. Blood samples were taken from all adult animals for bioanalytical of manganese analysis prior to dosing, prior to mating and prior to weaning/necropsy.There were no deaths related to treatment, though respiratory tract effects were observed in F0 animals in the mid and high dose animals. Body weight and food consumption were affected at high dose in both generation. There were no treatment-related effects on the oestrous cycles, mating performance, sexual maturity, fertility or duration of gestation or litter size, the sperm motility, count of morphology (sperm) or the ovary follicle scoring in either generation.The No Observed Effect Level (NOEL) for reproductive performance was considered to be the target dose level of 20μg/L.Based on these findings, manganese chloride could not be considered a reprotoxicant under these conditions of exposure. Therefore, soluble and insoluble forms of inorganic manganese compounds by extrapolation cannot be considered as reprotoxicants.

Altered neural connectivity in adult female rats exposed to early life social stress

The use of a variety of neuroanatomical techniques has led to a greater understanding of the adverse effects of stress on psychiatric health. One recent advance that has been particularly valuable is the development of resting state functional connectivity (RSFC) in clinical studies. The current study investigates changes in RSFC in F1 adult female rats exposed to the early life chronic social stress (ECSS) of the daily introduction of a novel male intruder to the cage of their F0 mothers while the F1 pups are in the cage. This ECSS for the F1 animals consists of depressed maternal care from their F0 mothers and exposure to conflict between their F0 mothers and intruder males. Analyses of the functional connectivity data in ECSS exposed adult females versus control females reveal broad changes in the limbic and reward systems, the salience and introspective socioaffective networks, and several additional stress and social behavior associated nuclei. Substantial changes in connectivity were found in the prefrontal cortex, nucleus accumbens, hippocampus, and somatosensory cortex. The current rodent RSFC data support the hypothesis that the exposure to early life social stress has long term effects on neural connectivity in numerous social behavior, stress, and depression relevant brain nuclei. Future conscious rodent RSFC studies can build on the wealth of data generated from previous neuroanatomical studies of early life stress and enhance translational connectivity between animal and human fMRI studies in the development of novel preventative measures and treatments.

Engineered non-Mendelian inheritance of entire parental genomes in C. elegans.

The ability to rewrite the rules of genetic segregation would open new possibilities in diverse areas of biotechnology ranging from breeding to epigenetics. Here we engineer non-Mendelian inheritance of the entire maternal or paternal genome in Caenorhabditis elegans by changing the structure of the mitotic spindle during the first cell division of the zygote. Using germline-specific overexpression of a single protein, the conserved microtubule force regulator GPR-1, we increase forces that pull on spindle poles to convert the single bipolar mitotic spindle to two monopolar spindles. This generates two-cell embryos in which one cell contains only the maternal chromosomes and the other cell contains only the paternal chromosomes. As the embryo develops, each cell of the animal, including the germ cells, contains the genetic material of only one parent, resulting in hybrid F1 animals. Progeny of these animals (F2) inherit either only F0 maternal or only F0 paternal chromosomes, and thus descend from only either of their grandparents' gametes.

Variation in the nasal cavity of baboon hybrids with implications for late Pleistocene hominins

Hybridization is increasingly proving to be an important force shaping human evolution. Comparisons of both ancient and modern genomes have provided support for a complex evolutionary scenario over the past million years, with evidence for multiple incidents of gene exchange. However, to date, genetic evidence is still limited in its ability to pinpoint the precise time and place of ancient admixture. For that we must rely on evidence of admixture from the skeleton. The research presented here builds on previous work on the crania of baboon hybrids, focusing on the nasal cavity of olive baboons, yellow baboons, and first generation (F1) hybrids. The nasal cavity is a particularly important anatomical region for study, given the clear differentiation of this feature in Neanderthals relative to their contemporaries, and therefore it is a feature that will likely differ in a distinctive manner in hybrids of these taxa. Metric data consist of 45 linear, area, and volume measurements taken from CT scans of known-pedigree baboon crania. Results indicate that there is clear evidence for differences among the nasal cavities of the parental taxa and their F1 hybrids, including a greater degree of sexual dimorphism in the hybrids. There is also some evidence for transgressive phenotypes in individual F1 animals. The greatest amount of shape variation occurs in the anterior bony cavity, the choana, and the mid-nasopharynx. Extrapolating our results to the fossil record, we would expect F1 hybrid fossils to have larger nasal cavities, on average, than either parental taxon, with overall nasal cavity shape showing the most profound changes in regions that are distinct between the parental taxa (e.g., anterior nasal cavity). We also expect size and shape differences to be more pronounced in male F1 hybrids than in females. Because of pronounced anterior nasal cavity differences between Neanderthals and their contemporaries, we suggest that this model might be effective for examining the fossil record of late Pleistocene contact.

Dnd knockout ablates germ cells and demonstrates germ cell independent sex differentiation in Atlantic salmon.

Introgression of farmed salmon escapees into wild stocks is a major threat to the genetic integrity of wild populations. Using germ cell-free fish in aquaculture may mitigate this problem. Our study investigated whether it is possible to produce germ cell-free salmon in F0 by using CRISPR-Cas9 to knock out dnd, a factor required for germ cell survival in vertebrates. To avoid studying mosaic animals, sgRNA targeting alb was simultaneously used as a visual tracer since the phenotype of alb KO is complete loss of pigmentation. Induced mutations for the tracer (alb) and the target (dnd) genes were highly correlated and produced germ cell-less fish lacking pigmentation, underlining the suitability of alb KO to serve as tracer for targeted double allelic mutations in F0 animals in species with prohibitively long generation times. This is also the first report describing dnd knockout in any fish species. Analyzing gene expression and histology of dnd KO fish revealed that sex differentiation of the somatic compartment does not depend on the presence of germ cells. However, the organization of the ovarian somatic compartment seems compromised in mutant fish.

Exposure to opiates in female adolescents alters mu opiate receptor expression and increases the rewarding effects of morphine in future offspring

Prescription opiate use and abuse has increased dramatically over the past two decades, including increased use in adolescent populations. Recently, it has been proposed that use during this critical period may affect future offspring even when use is discontinued prior to conception. Here, we utilize a rodent model to examine the effects of adolescent morphine exposure on the reward functioning of the offspring. Female Sprague Dawley rats were administered morphine for 10 days during early adolescence (post-natal day 30–39) using an escalating dosing regimen. Animals then remained drug free until adulthood at which point they were mated with naïve males. Adult offspring (F1 animals) were tested for their response to morphine-induced (0, 1, 2.5, 5, and 10 mg/kg, s.c.) conditioned place preference (CPP) and context-independent morphine-induced sensitization. Naïve littermates were used to examine mu opiate receptor expression in the nucleus accumbens and ventral tegmental area. Results indicate that F1 females whose mothers were exposed to morphine during adolescence (Mor-F1) demonstrate significantly enhanced CPP to the lowest doses of morphine compared with Sal-F1 females. There were no differences in context-independent sensitization between maternal treatment groups. Protein expression analysis showed significantly increased levels of accumbal mu opiate receptor in Mor-F1 offspring and decreased levels in the VTA. Taken together, these findings demonstrate a shift in the dose response curve with regard to the rewarding effects of morphine in Mor-F1 females which may in part be due to altered mu opiate receptor expression in the nucleus accumbens and VTA.

A dietary two-generation reproductive toxicity study of (2R,4R)-monatin salt in Crl:CD(SD) rats

(2R,4R)-Monatin salt [sodium/potassium 2R,4R-2-amino-4-carboxy-4-hydroxy-5-(3-indolyl) pentanoate] was fed at 5000, 15,000, or 35,000 ppm to Crl:CD(SD) rats over two generations. Reduced body weights were observed at all dose levels. Sustained effect on body weight gain at 35,000 ppm in the F0 and F1 parental animals was associated with lower feed efficiency, soft stool, and slightly lower numbers of implantation sites. Lower numbers of pups born and live litter size at 35,000 ppm were considered secondary to slightly lower numbers of former implantation sites in the dams. Spermatogenic endpoints, estrous cyclicity, reproductive performance, mean gestation length, and parturition were unaffected in the F0 and F1 generations. There were no effects on F1 and F2 generation postnatal survival. Reduced pre-weaning pup body weights at 35,000 ppm resulted in lower F1 and F2 body weights at study termination. Slight delays in pubertal landmarks in the F1 offspring were considered secondary to the reduced pup body weights. The no-observed-adverse-effect level (NOAEL) was 15,000 ppm for systemic, reproductive, and neonatal effects based on test article-related effects on body weight and food efficiency, slight decrease in maternal implantation sites and corresponding reduction in live litter size, and reductions in pre-weaning pup body weights at 35,000 ppm.

Sub-chronic (13-week) oral toxicity study, preceded by an in utero exposure phase and genotoxicity studies with fish source phosphatidylserine in rats

The safety of fish phosphatidylserine (PS) conjugated to DHA (InCog™) was examined in a series of toxicology studies as first step to support future use in infants and general population using in vitro genotoxicity tests and in a sub-chronic toxicity study with an in-utero exposure phase. PS is a major lipid in the cell membrane, active in various membrane-mediated processes. PS-DHA, present in human milk, has been suggested to be important for early brain development. Rats were exposed to diets containing 1.5%, 3% or 4.5% InCog or two control diets. Parental (F0) animals were fed throughout mating, gestation and lactation. Subsequently, a subchronic, 13-week study was conducted on the F1 animals followed by 4 weeks of recovery.The genotoxicity tests showed no mutagenicity potential. No significant toxicological findings were found in the F0 rats or the F1 pups. In the 13-weeks study, an increase in the presence of renal minimal-mild multifocal corticomedullary mineralization was noted in nine females of the high-dose group. This change was not associated with any inflammatory or degenerative changes in the kidneys. The no-observed-adverse-effect level (NOAEL) in the present study was placed at 3% in the diet (mid-dose group), equivalent to an overall intake of at least 2.1 g InCog/kg bw/day in the F1 generation.

Paternal BPA exposure in early life alters Igf2 epigenetic status in sperm and induces pancreatic impairment in rat offspring

Exposure to endocrine disruptors in utero appears to alter epigenetics in the male germ-line and subsequently promote adult-onset disease in subsequent generations. Fetal exposure to bisphenol A (BPA), a highly prevalent endocrine disruptor in environment, has been shown to alter epigenetic modification and result in glucose intolerance in adulthood. However, whether fetal exposure to BPA can induce epigenetic modification and phenotypic changes in their subsequent offspring are still unclear. The present study was designed to investigate whether exposure to BPA in early life induced glucose intolerance in the offspring through male germ line, and the underlying epigenetic molecular basis. F0 pregnant SD rats were received corn oil or 40 μg/kg/day of BPA during gestation and lactation. F1 male rats were maintained to generate F2 offspring by mating with untreated female rats. Both the F1 rats after weaning and the F2 offspring were not received any other treatments. Our results showed that male F2 offspring in the BPA group exhibited glucose intolerance and β-cell dysfunction. Decreased expression of Igf2 and associated hypermethylation of Igf2 were observed in islets of male F2 offspring. In addition, similar effects were observed in female F2 animals, but the effects were more pronounced in males. Moreover, abnormal expression and methylation of Igf2 was observed in sperm of adult F1 male rats, indicating that epigenetic modification in germ cells can be partly progressed to the next generation. Overall, our study suggests that BPA exposure during early life can result in generational transmission of glucose intolerance and β-cell dysfunction in the offspring through male germ line, which is associated with hypermethylation of Igf2 in islets. The changes of epigenetics in germ cells may contribute to this generational transmission.

A comparison of alternative random regression and reaction norm models for whole genome predictions.

Whole genome prediction (WGP) based on high density SNP marker panels is known to improve the accuracy of breeding value (BV) prediction in livestock. However, these accuracies can be compromised when genotype by environment interaction (G×E) exists but is not accounted for. Reaction norm (RN) and random regression (RR) models have proven to be useful in accounting for G×E in pre-WGP evaluations by modeling BV as linear or higher order functions of environmental or temporal covariates. We extend these RR/RN models based on several alternative specifications for SNP-specific intercepts and linear slopes on environmental covariates. One specification is based on bivariate normality (BVN) of SNP-specific intercepts and slopes, whereas 2 others, IW-BayesA and based on inverted Wishart (IW) extensions IW-BayesB, are, respectively, bivariate Student t extensions of currently popular models without (BayesA) or with (BayesB) variable selection. We highlight alternative specifications based on the square root free Cholesky decomposition (CD) of SNP-specific variance-covariance (VCV) matrices in an attempt to better differentially model environmentally sensitive from environmentally robust QTL. Two CD specifications were considered with (CD-BayesB) or without (CD-BayesA) any variable selection on intercept and slope effects. We compared each of the 5 models based on an RN simulation study. Six scenarios were considered based on differences in overall genetic correlations between SNP-specific intercept and slope effects as well as on heritabilities and numbers of environmentally robust versus sensitive QTL. In most scenarios, IW-BayesA had the greatest accuracy, whereas CD-BayesB exhibited the greatest accuracy in low complexity architectures (i.e., low number of QTL). In an RR application of a Duroc × Pietrain resource population at Michigan State University, 5,271 SNP markers and 928 F2 animals with known pedigree were analyzed for backfat thickness at wk 10, 13, 16, 19, and 22. SNP-based RR methods had a 2.5% greater (P < 0.0001) cross-validation accuracy for predicting phenotypes than the SNP-based conventional BayesA/BayesB and/or pedigree based RR BLUP; however, none of the proposed RR models had performances that were different from each other.

Candidate genes underlying heritable differences in reproductive seasonality between wild and domestic rabbits

Reproductive seasonality is a trait that often differs between domestic animals and their wild ancestors, with domestic animals showing prolonged or even continuous breeding seasons. However, the genetic basis underlying this trait is still poorly understood for most species, and because environmental factors and resource availability are known to play an important role in determining breeding seasons, it is also not clear in most cases to what extent this phenotypic shift is determined by the more lenient captive conditions or by genetic factors. Here, using animals resulting from an initial cross between wild and domestic rabbits followed by two consecutive backcrosses (BC1 and BC2) to wild rabbits, we evaluated the yearly distribution of births for the different generations. Similar to domestic rabbits, F1 animals could be bred all year round but BC1 and BC2 animals showed a progressive and significant reduction in the span of the breeding season, providing experimental evidence that reduced seasonal breeding in domestic rabbits has a clear genetic component and is not a simple by-product of rearing conditions. We then took advantage of a recently published genome-wide scan of selection in the domesticated lineage and searched for candidate genes potentially associated with this phenotypic shift. Candidate genes located within regions targeted by selection include well-known examples of genes controlling clock functions (CRY1 and NR3C1) and reproduction (PRLR).

Genetic Association of the Porcine C9 Complement Component with Hemolytic Complement Activity.

The complement system is a part of the natural immune regulation mechanism against invading pathogens. Complement activation from three different pathways (classical, lectin, and alternative) leads to the formation of C5-convertase, an enzyme for cleavage of C5 into C5a and C5b, followed by C6, C7, C8, and C9 in membrane attack complex. The C9 is the last complement component of the terminal lytic pathway, which plays an important role in lysis of the target cells depending on its self-polymerization to form transmembrane channels. To address the association of C9 with traits related to disease resistance, the complete porcine C9 cDNA was comparatively sequenced to detect single nucleotide polymorphisms (SNPs) in pigs of the breeds Hampshire (HS), Duroc (DU), Berlin miniature pig (BMP), German Landrace (LR), Pietrain (PIE), and Muong Khuong (Vietnamese potbelly pig). Genotyping was performed in 417 F2 animals of a resource population (DUMI: DU×BMP) that were vaccinated with Mycoplasma hyopneumoniae, Aujeszky diseases virus and porcine respiratory and reproductive syndrome virus at 6, 14 and 16 weeks of age, respectively. Two SNPs were detected within the third exon. One of them has an amino acid substitution. The European porcine breeds (LR and PIE) show higher allele frequency of these SNPs than Vietnamese porcine breed (MK). Association of the substitution SNP with hemolytic complement activity indicated statistically significant differences between genotypes in the classical pathway but not in the alternative pathway. The interactions between eight time points of measurement of complement activity before and after vaccinations and genotypes were significantly different. The difference in hemolytic complement activity in the both pathways depends on genotype, kind of vaccine, age and the interaction to the other complement components. These results promote the porcine C9 (pC9) as a candidate gene to improve general animal health in the future.