Imprinted Effects Research Articles

Genetic analysis of parent-of-origin effects on growth traits and yearling greasy fleece weight in Raeini Cashmere goat

Pedigree on 7253 individuals and data information on growth traits and greasy yearling fleece weight collected from 1979 to 2013 at the Breeding Station of Raeini Cashmere goat, south-east of Iran, were used for genetic analysis of parent of origin effects for these traits using a gametic relationship matrix. The studied traits included birth weight (BW; 4747 records), weaning weight (WW; 3268 records), six months weight (6 MW; 2855 records), nine months weight (9 MW; 1407 records), yearling weight (YW; 1013 records), and yearling greasy fleece weight (YFW; 1272 records). Models including or excluding imprinting (maternal and paternal) effects were compared by applying Akaike Information Criterion (AIC). Paternal imprinting effects did not influence any of the studied traits. Maternal imprinting effects explained 9%, 6%, 9%, 18%, and 6% of phenotypic variances for WW, 6 MW, 9 MW, YW, and YFW, respectively. By including the maternal imprinting effects in the model used for genetic analysis, direct heritability estimates for WW (from 0.04 to 0.01), 9 MW (0.24–0.15), YW (from 0.31 to 0.14), and YFW (0.18–0.09) were decreased, implying a considerable proportion of the maternal imprinting effects for these traits may overlap with direct additive genetic effects. BW did not influence by imprinting effects. Strong maternal imprinting correlations among body weights at different ages (except for BW) showed that WW, 6 MW, 9 MW, and YW share similar genes with maternally imprinted effects. It means that the imprinting effects of genes are not limited to a specific stage of life and can be active in different stages of growth. Maternal imprinting correlation estimates between YFW and other traits were not statistically significant. Therefore, imprinting effects may be crucial for the genetically evaluating of these traits in the Raeini Cashmere goat.

Replicated Pattern Formation and Recognition Properties of 2,4-Dichlorophenoxyacetic Acid-Imprinted Polymers Using Colloidal Silica Array Molds.

Surface imprinting is an effective and simple method to fabricate and retain imprinted templates and recognizable nanocavities after template extraction. The imprinted effects can be controlled depending on the surface morphological changes. In general, a planar film has a limited area compared to a structured film with relatively higher surface-to-volume (S/V) ratio (A/A0), leading to the conventional sensing response upon the functionality of monomers in a fixed chemical composition. To increase the limited sensing properties and develop simple fabrication of porous arrays on a large area, we herein demonstrate the 2,4-dichlorophenoxyacetic acid (2,4-D, herbicide)-imprinted porous thin film lithographically patterned using photopolymerization and silica colloidal array as a master mold, derived by a unidirectional rubbing method. The resonant frequency changes with respect to the adsorption of 2,4-D molecules on a template-extracted porous poly(MAA-co-EGDMA) (MIP) film in a 10−1 mM aqueous solution of 2,4-D for 1 h, and when compared to the planar MIP film, the higher sensing response (Δf = −283 ± 7 Hz ≈ 1543 ± 38 ng/cm2) appears on the porous MIP film due to the specific recognition toward the more accessible templated cavities of the structured porous array, indicating an imprinting effect (If) value of 3.5. In addition, a higher selectivity for 2,4-D was also displayed on the porous MIP film compared to other herbicides. From these results, it was revealed that these improved sensing properties can be determined from the effects of various parameters (template functionality, film structuring, hydroxyl groups of silica colloids, etc.).

A Social Homophily Model of Political Ties in Emerging Economies

While resource dependence theorists have indicated that firms connect with political powers for desirable resources, little attention has been directed at the social foundations that foster firms’ political ties. We develop a framework that specifies how the social homophily and heterophily of firms with political powers affect the formation of political ties in turbulent environments. We use data of listed Taiwanese firms that experienced an unexpected regime change to show that social homophily of a firm with the political regime promotes ties between them, whereas social heterophily of a firm with the political regime deters its ties with the regime. Some types of homophily persistently promote the firm’s ties to its original political ally despite environmental changes. However, such imprinted effects of homophily weaken when the firm operates in regulated industries.

A Statistical Design for Testing Transgenerational Genomic Imprinting in Natural Human Populations

Genomic imprinting is a phenomenon in which the same allele is expressed differently, depending on its parental origin. Such a phenomenon, also called the parent-of-origin effect, has been recognized to play a pivotal role in embryological development and pathogenesis in many species. Here we propose a statistical design for detecting imprinted loci that control quantitative traits based on a random set of three-generation families from a natural population in humans. This design provides a pathway for characterizing the effects of imprinted genes on a complex trait or disease at different generations and testing transgenerational changes of imprinted effects. The design is integrated with population and cytogenetic principles of gene segregation and transmission from a previous generation to next. The implementation of the EM algorithm within the design framework leads to the estimation of genetic parameters that define imprinted effects. A simulation study is used to investigate the statistical properties of the model and validate its utilization. This new design, coupled with increasingly used genome-wide association studies, should have an immediate implication for studying the genetic architecture of complex traits in humans.

Sex dependent imprinting effects on complex traits in mice.

BackgroundGenomic imprinting is an epigenetic source of variation in quantitative traits that results from monoallelic gene expression, where commonly either only the paternally- or the maternally-derived allele is expressed. Imprinting has been shown to affect a diversity of complex traits in a variety of species. For several such quantitative traits sex-dependent genetic effects have been discovered, but whether imprinting effects also show such sex-dependence has yet to be explored. Moreover, theoretical work on the evolution of sex-dependent genomic imprinting effects makes specific predictions about the phenotypic patterns of such effects, which, however, have not been assessed empirically to date.ResultsUsing a genome-scan for loci affecting a set of complex growth and body composition traits from an intercross between two divergent mouse strains, we investigated possible sex-dependent imprinting effects. Our results demonstrate for the first time the existence of genomic imprinting effects that depend on sex and are not related to sex-chromosome effects. We detected a total of 13 loci on 11 chromosomes that showed significant differences between the sexes in imprinting effects. Most loci showed imprinting effects in only one sex, with eight imprinted effects found in males and six in females. One locus showed sex-dependent imprinting effects in both sexes for different traits. The absence of an imprinting effect in one sex was not necessarily indicative of the overall inactivity of the locus in that sex, as for several loci a significant additive or dominance effect was detected. Moreover, three loci exhibited significant additive effects in both sexes but their imprinting effect was restricted to one sex.ConclusionOur results clearly show that imprinting effects can be sex-dependent and also suggest that new candidate imprinted loci can be detected when taking account of sex-specific imprinting effects. However, predictions made about the evolution of sex-dependent imprinting effects and associated phenotypic patterns cannot be unequivocally supported at present and further research into the selection pressures applied to the strains of mice used in our study is required.

Shape-selective covalent binding in bulk, microporous imprinted silica

The first demonstration of shape-selective covalent binding in bulk, microporous imprinted silica is provided. The synthetic approach utilizes acid-catalyzed sol–gel hydrolysis and condensation of tetraethyl orthosilicate with a carbamate-based organosilane imprint for synthesis of hybrid organic–inorganic materials. Cleavage of the immobilized imprint carbamate synthesizes isolated primary or secondary amines within templated pockets that are complementary to the imprint size and shape. Two chiral imprints are investigated. The imprint based upon a phenyl alcohol leaves an achiral primary amine after carbamate deprotection, while the imprint based upon a proline scaffold leaves behind a chiral secondary amine after carbamate deprotection. Binding selectivity of the imprinted silicas is investigated via the covalent attachment of racemic isocyanate mixtures for simultaneous assessment of shape-selectivity and enantioselectivity. Shape-selectivity for the binding of α-methylbenzyl isocyanate over a 1-naphthyl homologue was observed across a range of materials. Investigation of the origin of selectivity by using particles of varying size shows that the selectivity partially arises from bulk sieving effects of mass transport limitations in the material network. However, due to significant particle size distributions, it is possible that the system exists in an intermediate regime where binding results are a complex mixture of sieving and shape-selective imprinted site effects. The results are consistent with the previous observation that amines in bulk, microporous imprinted silica are isolated and have been confined to a microporous network. This confinement of the bulky imprints, which would be difficult to accomplish via a post-synthetic grafting procedure, illustrates the synthetic utility of the imprinting method.

Xlr3b is a new imprinted candidate for X-linked parent-of-origin effects on cognitive function in mice

Imprinted genes show differential expression between maternal and paternal alleles as a consequence of epigenetic modification that can result in 'parent-of-origin' effects on phenotypic traits. There is increasing evidence from mouse and human studies that imprinted genes may influence behavior and cognitive functioning. Previous work in girls with Turner syndrome (45,XO) has suggested that there are X-linked parent-of-origin effects on brain development and cognitive functioning, although the interpretation of these data in terms of imprinted gene effects has been questioned. We used a 39,XO mouse model to examine the influence of the parental origin of the X chromosome on cognitive behaviors and expression of X-linked genes in brain. Our findings confirm the existence of X-linked imprinted effects on cognitive processes and identify a new maternally expressed imprinted gene candidate on the X chromosome, Xlr3b, which may be of importance in mediating the behavioral effects.

Imprinted genes and mental dysfunction

There is a rapidly accumulating body of evidence from family, adoption and twin studies suggestive of a genetic component to many common mental disorders. In some cases, the transmission of abnormalities has been shown to be dependent upon the sex of the parent from whom they are inherited. Such ‘parent-of-origin effects’ may be explained by a number of genetic mechanisms, one of which is ‘genomic imprinting’. In imprinted genes one allele is silenced according to its parental origin. This in turn means that imprinted traits are passed down the maternal or paternal line, in contrast to the more frequent Mendelian mode of inheritance that is indifferent to the parental origin of the allele. In the present review, we survey the evidence for the influence of imprinted genes on a number of mental disorders, ranging from explicit imprinted conditions, where in some cases abnormalities have been mapped to particular gene candidates, to examples where the evidence for parent-of-origin effects is less strong. We also consider, briefly, the wider implications of imprinted effects on mental dysfunction, in particular with respect to evolutionary pressures on mammalian brain development and function.

Gametic imprinting effects on rate and composition of pig growth

Genetic improvement schemes in livestock are based on the assumption that the expression of relevant genes is independent of parent of origin. Until now no evidence has been found to reject this assumption. The present study on three purebred pig populations, however, shows that a significant proportion of the phenotypic variance in backfat thickness (5-7%) can be explained by genes subject to paternal imprinting. The implication is that there are genes affecting backfat that are expressed only when derived from the paternal gamete. Paternal imprinted effects explained 1-4% of the phenotypic variation for growth rate. Maternal imprinted effects were heavily confounded with heritable maternal environmental effects. When modelled separately, these effects explained 2-5% and 3-4% of the phenotypic variance in backfat thickness and growth rate, respectively. Gametic imprinting may have consequences for the optimization of breeding programmes, especially in crossbreeding systems with specialized sire and dam lines.