Epigenetics: The link between nature and nurture

Abstract

While the eukaryotic genome is the same throughout all somatic cells in an organism, there are specific structures and functions that discern one type of cell from another. These differences are due to the cell's unique gene expression patterns that are determined during cellular differentiation. Interestingly, these cell-specific gene expression patterns can be affected by an organism's environment throughout its lifetime leading to phenotypical changes that have the potential of altering risk of some diseases. Both cell-specific gene expression signatures and environment mediated changes in expression patterns can be explained by a complex network of modifications to the DNA, histone proteins and degree of DNA packaging called epigenetic marks. Several areas of research have formed to study these epigenetic modifications, including DNA methylation, histone modifications, chromatin remodeling and microRNA (miRNA). The original definition of epigenetics incorporates inheritable but reversible phenomena that affect gene expression without altering base pairs. Even though not all of the above listed epigenetic traits have demonstrated heritability, they can all alter gene transcription without modification to the underlying genetic sequence. Because these epigenetic patterns can also be affected by an organism's environment, they serve as an important bridge between life experiences and phenotypes. Epigenetic patterns may change throughout ones lifespan, by an early life experience, environmental exposure or nutritional status. Epigenetic signatures influenced by the environment may determine our appearance, behavior, stress response, disease susceptibility, and even longevity. The interaction between types of epigenetic modifications in response to environmental factors and how environmental cues affect epigenetic patterns will further elucidate how gene transcription can be affectively altered.

Women’s Diet During Pregravid Preparation, Pregnancy and Lactation

“…Действительно, было показано, что если женщины на протяжении всей беременности соблюдали диету, дефицитную по белку, то их новорожденные дети имели метаболический фенотип с признаками, характер-ными для кардиометаболических заболеваний челове-ка, включающих гипертензию, избыточную массу тела, повреждение гомеостаза глюкозы, дислипидемию и сосу-дистую дисфункцию [4]. Собаки, получавшие низкобелко-вую диету, производили потомство с такими дефектами развития, как снижение метилирования и увеличение экспрессии гена PPAR␣, контролирующего жировой обмен в печени [7]. Также было показано, что низкобелковая диета у свиней осуществляет глобальное ДНК-метили ро ва-ние у новорожденного потомства через экспрессию ДНК-метилтрансферазы в печени и скелетной мускулатуре [7].…”

“…Новое направление в науке -нутритивная эпиге-нетика -дает возможное объяснение тому, как питание человека на любой стадии онтогенеза может оказывать влияние на развитие многих распространенных заболева-ний путем изменения экспрессии генов (без повреждения самой генной последовательности) с краткосрочными или отдаленными последствиями для организма [3][4][5]. В свою очередь, повреждения в эпигенетической регуляции генов могут приводить к глубоким изменениям в фенотипе [6,7]. …”

Epigenetic Alterations in Aging and Aging-Associated Diseases: Review

“…RISC kompleksi Argonuat proteinleri ile etkileşime girer ve onlar topluca hedef mRNA'ları susturmak için harekete geçerler. 60,61 miRNA'lar ilk olarak Caenorhabditis elegans'da keşfedilmiştir. miRNA'ların yaşlanmadaki rolü C. elegans ve farelerde yapılan çalışmalarla belirtilmiş ve bu çalışmalar sonunda miRNA'ların gen düzenlenmesi ve baskılanmasında önemli olduğu görülmüştür.…”

Neuroepigenetics: Prospects and Illusions

“…The concept of epigenetics, introduced by Conrad Waddington in 1942, and its spectacular evolution, from a biotechnological perspective, has been of great help for the past 10 years in the understanding of gene regulation and expression (functional genomics), neurogenomics, and pathogenetics of CNS disorders [3][4][5][6][7].…”

“…Preconceptional parental exposure to environmental stimuli may determine the offspring's phenotype via meiotically and mitotically heritable epigenetic mechanisms [3], and exposure to diverse external elements (nutrition, pollutants, drugs, toxins) may condition several categories of human diseases. Consequently, epigenetic aberrations contribute to the pathogenesis of neurodevelopmental, imprinting, neuropsychiatric, and agerelated neurodegenerative disorders [2].…”