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Epigenetic Differences (epigenetic + difference)
Selected AbstractsNot really identical: Epigenetic differences in monozygotic twins and implications for twin studies in psychiatry,AMERICAN JOURNAL OF MEDICAL GENETICS, Issue 2 2009F. Nipa Haque Abstract Classical twin studies in the field of psychiatry generally fall into one of two categories: (1) those designed to identify environmental risk factors causing discordance in monozygotic (MZ) twins and (2) those geared towards identifying genetic risk factors. However, neither environment nor differences in DNA sequence can fully account for phenotypic discordance among MZ twins. The field of epigenetics , DNA modifications that can affect gene expression , offers new models to understand discordance in MZ twins. In the past, MZ twins were regarded as genetically-identical controls for differing environmental conditions. In contrast, the evolving current concept is that epigenetic differences between MZ twins may modulate differences in diverse phenotype, from disease to personality. In this article, we review some twin studies, and discuss the dynamic interactions between stochastic, environmental, and epigenetic variables that influence neurobiological phenotypes. © 2009 Wiley-Liss, Inc. [source] MicroRNAs, the epigenetic memory and climatic adaptation in Norway spruceNEW PHYTOLOGIST, Issue 4 2010Igor A. Yakovlev Summary ,Norway spruce expresses a temperature-dependent epigenetic memory from the time of embryo development, which thereafter influences the timing bud phenology. MicroRNAs (miRNAs)are endogenous small RNAs, exerting epigenetic gene regulatory impacts. We have tested for their presence and differential expression. ,We prepared concatemerized small RNA libraries from seedlings of two full-sib families, originated from seeds developed in a cold and warm environment. One family expressed distinct epigenetic effects while the other not. We used available plant miRNA query sequences to search for conserved miRNAs and from the sequencing we found novel ones; the miRNAs were monitored using relative real time-PCR. ,Sequencing identified 24 novel and four conserved miRNAs. Further screening of the conserved miRNAs confirmed the presence of 16 additional miRNAs. Most of the miRNAs were targeted to unknown genes. The expression of seven conserved and nine novel miRNAs showed significant differences in transcript levels in the full-sib family showing distinct epigenetic difference in bud set, but not in the nonresponding full-sib family. Putative miRNA targets were studied. ,Norway spruce contains a set of conserved miRNAs as well as a large proportion of novel nonconserved miRNAs. The differentially expression of specific miRNAs indicate their putative participation in the epigenetic regulation. [source] Aberrant methylation of p14ARF, p15INK4b and p16INK4a genes and location of the primary site in pulmonary squamous cell carcinomaPATHOLOGY INTERNATIONAL, Issue 8 2004Osamu Furonaka Aberrant methylation of cytosines in CpG islands of the promoter regions of tumor suppressor genes is found in human tumors as a common mechanism of gene silencing. We investigated the methylation status of the chromosome 9p21 gene cluster (p14ARF, p15INK4b and p16INK4a genes) by methylation-specific polymerase chain reaction in 20 central and 40 peripheral types of pulmonary squamous cell carcinoma (SqCC) in order to determine the differences between the pathogeneses of the central and peripheral types of SqCC. The frequencies of methylation were 30% for the p14ARF gene, 20% for the p15INK4b gene and 40% for the p16INK4a gene in the central type and 25% for the p14ARF gene, 10% for the p15INK4b gene and 38% for the p16INK4a gene in the peripheral type. Cases in which there was methylation of the p16INK4a gene had a higher smoking index in the peripheral type (P = 0.007). This trend was not detected in the central type. Methylation of two or three genes was observed in 55% of methylation in at least one gene of the central type but in only 17% of the peripheral type. This overlap methylation of the chromosome 9p21 gene cluster was found more frequently in the central type (P = 0.02). These findings suggest one of the epigenetic differences between the central and peripheral types of SqCC. [source] Not really identical: Epigenetic differences in monozygotic twins and implications for twin studies in psychiatry,AMERICAN JOURNAL OF MEDICAL GENETICS, Issue 2 2009F. Nipa Haque Abstract Classical twin studies in the field of psychiatry generally fall into one of two categories: (1) those designed to identify environmental risk factors causing discordance in monozygotic (MZ) twins and (2) those geared towards identifying genetic risk factors. However, neither environment nor differences in DNA sequence can fully account for phenotypic discordance among MZ twins. The field of epigenetics , DNA modifications that can affect gene expression , offers new models to understand discordance in MZ twins. In the past, MZ twins were regarded as genetically-identical controls for differing environmental conditions. In contrast, the evolving current concept is that epigenetic differences between MZ twins may modulate differences in diverse phenotype, from disease to personality. In this article, we review some twin studies, and discuss the dynamic interactions between stochastic, environmental, and epigenetic variables that influence neurobiological phenotypes. © 2009 Wiley-Liss, Inc. [source] Characterization of gene localization and accessibility in DHFR-amplified CHO cellsBIOTECHNOLOGY PROGRESS, Issue 1 2009Zhou Jiang Abstract Efficient transcription is critical for high yields of recombinant proteins by mammalian cells. We previously reported that dihydrofolate reductase (DHFR)-mediated gene amplification can augment transcriptional rates as well as increasing gene copy numbers in Chinese hamster ovary (CHO) cells.1 In an attempt to elucidate the mechanisms involved, we have employed several approaches to identify the epigenetic differences between cell clones with varying transcriptional rates. Transgene placement and accessibility varies between unrelated parental cell clones with differential transcriptional rates. However, we did not observe any apparent epigenetic differences between parental clones and their amplified progeny, indicating undiscovered regulatory mechanisms are responsible for the augmentation of transcriptional rates upon DHFR-mediated amplification. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Epigenetic modulation at birth , altered DNA-methylation in white blood cells after Caesarean sectionACTA PAEDIATRICA, Issue 7 2009T Schlinzig Abstract Aim:, Delivery by C-section (CS) has been associated with increased risk for allergy, diabetes and leukaemia. Whereas the underlying cause is unknown, epigenetic change of the genome has been suggested as a candidate molecular mechanism for perinatal contributions to later disease risk. We hypothesized that mode of delivery affects epigenetic activity in newborn infants. Methods:, A total of 37 newborn infants were included. Spontaneous vaginal delivery (VD) occurred in 21, and 16 infants were delivered by elective CS. Blood was sampled from the umbilical cord and 3,5 days after birth. DNA-methylation was analyzed in leucocytes. Results:, Infants born by CS exhibited higher DNA-methylation in leucocytes compared with that of those born by VD (p < 0.001). After VD, newborn infants exhibited stable levels of DNA-methylation, as evidenced by comparing cord blood values with those 3,5 days after birth (p = 0.55). On postnatal days 3,5, DNA-methylation had decreased in the CS group (p = 0.01) and was no longer significantly different from that of VD (p = 0.10). Conclusion:, DNA-methylation is higher in infants delivered by CS than in infants vaginally born. Although currently unknown how gene expression is affected, or whether epigenetic differences related to mode of delivery are long-lasting, our findings open a new area of clinical research with potentially important public health implications. 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