Importance Of Imprinting Research Articles

Imprinting and Reproductive Health: A Toxicological Perspective

This overview discusses the role of imprinting in the development of an organism, and how exposure to environmental chemicals during fetal development leads to the physiological and biochemical changes that can have adverse lifelong effects on the health of the offspring. There has been a recent upsurge in the use of chemical products in everyday life. These chemicals include industrial byproducts, pesticides, dietary supplements, and pharmaceutical products. They mimic the natural estrogens and bind to estradiol receptors. Consequently, they reduce the number of receptors available for ligand binding. This leads to a faulty signaling in the neuroendocrine system during the critical developmental process of ‘imprinting’. Imprinting causes structural and organizational differentiation in male and female reproductive organs, sexual behavior, bone mineral density, and the metabolism of exogenous and endogenous chemical substances. Several studies conducted on animal models and epidemiological studies provide profound evidence that altered imprinting causes various developmental and reproductive abnormalities and other diseases in humans. Altered metabolism can be measured by various endpoints such as the profile of cytochrome P-450 enzymes (CYP450’s), xenobiotic metabolite levels, and DNA adducts. The importance of imprinting in the potentiation or attenuation of toxic chemicals is discussed.

Molecularly Imprinted Polymers with DNA Aptamer Fragments as Macromonomers.

Molecularly imprinted polymers (MIPs) are produced in the presence of a template molecule. After removing the template, the cavity can selectively rebind the template. MIPs are attractive functional materials with a low cost and high stability, but traditional MIPs often suffer from low binding affinity. This study employs DNA aptamer fragments as macromonomers to improve MIPs. The DNA aptamer for adenosine was first split into two halves, fluorescently labeled, and copolymerized into MIPs. With a fluorescence quenching assay, the importance of imprinting was confirmed. Further studies were carried out using isothermal titration calorimetry (ITC). Compared to the mixture of the free aptamer fragments, their MIPs doubled the binding affinity. Each free aptamer fragment alone cannot bind adenosine, whereas MIPs containing each fragment are effective binders. We further shortened one of the aptamer fragments, and the DNA length was pushed to as short as six nucleotides, yielding MIPs with a dissociation constant of 27 μM adenosine. This study provides a new method for preparing functional MIP materials by combining high-affinity biopolymer fragments with low-cost synthetic monomers, allowing higher binding affinity and providing a method for signaling binding based on DNA chemistry.

And Baby Makes Three: Genomic Imprinting in Plant Embryos

And Baby Makes Three: Genomic Imprinting in Plant Embryos

Acoustic Signals in Domestic Chicken (<i>Gallus gallus</i>): A Tool for Teaching Veterinary Ethology and Implication for language learning

In this study chicken were able to express about 30 sounds (Words/syllables) of which 19 were distinctly identified as: warning, alarm, contact, territorial, laying, nesting, mating, threat, submissive, distress, fear , contentment, food, dust bathing, perching, battle cries, privacy, dominance and time calls. And short sentences (A combination of two and three syllables/ cackle). There were also some sounds that were not deciphered. Local chicken have had a good sense of hearing to these sounds as observed from postural, visual and auditory displays. It was found that baby chicks from broody and non broody breeds responded to the acoustic stimulus. While the adults of the commercial breed, did not respond to the acoustic stimulus, showed less motor reactions, postural and vocal displays. Also they produced less syllables. It was concluded that they do not know the language. The songram indicate that chicken produced sound frequency ranging from 50Hz to 10 kHz, this hearing range is within the hearing realm of humans which is 20-20,000Hz. Thus, Birdsong can be used as a biological model of human language, and acoustic communication in chicken can be demonstrated to students without the requirement of special apparatus. The results showed the usefulness of the chicken model in teaching acoustic communication, animal behavior and the importance of imprinting in language learning.

Methods for Detecting Interactions between Imprinted Genes and Environmental Exposures Using Birth Cohort Designs with Mother-Offspring Pairs

Genomic imprinting is a form of epigenetic regulation in mammals in which the same allele of a gene is expressed differently depending on the parental origin of the allele. Traditionally, the detection of imprinted genes that affect complex diseases has been focused on linkage designs with pedigrees or case-parent designs with case-parent trios. In the past two decades, the birth cohort design with mother-offspring pairs has been applied to understand better the effect of environmental influences during pregnancy and beginning of life on the growth and development of children. No work has been done on the detection of imprinted genes using birth cohort designs. Moreover, although the importance of imprinting has been well recognized, no study has looked at how environmental exposures modify the effects of imprinted genes. In this study, we show that the proposed imprinting test using the birth cohort design with mother-offspring pairs is an efficient test for testing the interactions between imprinted genes and environmental exposures. Through extensive simulation studies and a real data application, the proposed imprinting test has demonstrated much improved power in detecting gene-environment interactions than that of a test assuming the Mendelian dominant model when the true underlying genetic model is imprinting.

The importance of imprinting in cloning

Cloning using nuclear transfer technology is an inefficient process in which most clones die before birth and survivors often display growth abnormalities. This is attributed to genetic imprinting – particular genes in the donor nucleus are permanently turned on or off. Imprinting appears to vary between donor nuclei, hence producing inefficiencies in the cloning process. In an effort to correlate gene expression with survival and foetal overgrowth, David Humphreys et al. (Science, 6 July) examined imprinted gene expression in both mice cloned by nuclear transfer and in the embryonic stem (ES) cell donor populations from which they were derived. Expression in the ES cell genome was found to be extremely unstable, as was the case with most of the cloned mice. What is most astonishing, is that despite widespread gene disregulation, many of the animals survived to adulthood, indicating a robust tolerance in mammalian development. The implication of the work is that even apparently normal cloned animals might have subtle abnormalities in gene expression. DM