Environmental influences in the establishment of the epigenetic landscape in children

我们每个细胞中的DNA并不是单独存在的，它通过与许多不同的蛋白质结合而被包装成称为染色体的复杂结构。根据细胞类型的不同，这些蛋白质在染色体长度上的分布也会有所不同，这种现象被称为表观遗传学，字面意思是‘高于DNA’。表观遗传学分析是研究蛋白质和其他分子如何在不改变DNA序列的情况下改变基因的活性。我们所有的细胞都利用表观遗传变化来帮助控制它们的生长和发育。有证据表明，饮食和环境影响我们的表观遗传学特征之间存在直接联系。最近的研究将成年人生活中许多健康问题的根源追溯到最早的发育时期--在子宫中度过的时间和生命的头几年。如果我们出生时体重较低，我们更有可能在以后的生活中生病。有确凿的证据表明，子宫内的环境对健康的出生体重(以及晚年的健康)至关重要，人们认为表观遗传学可能是这种环境、低出生体重和晚年健康之间缺失的一环。此外，越来越多的证据支持表观遗传去调节和疾病易感性之间的一般联系。然而，环境遗传影响对建立有缺陷的表观遗传标记的时机和总体贡献仍在很大程度上尚不清楚。双胞胎是研究这种联系的最佳模型，因为他们拥有相似的(但不是完全相同的环境)，有些拥有相同的基因构成。杰弗里·克雷格博士和他的团队将以双胞胎为例，研究产前环境中改变特定细胞的因素，这些因素会导致低出生体重并增加晚年的疾病风险。他们预测，这是通过表观遗传破坏引起的基因活性的特定变化来实现的。

The DNA in each of our cells does not exist alone, it is packaged into complex structures called chromosomes, through association with many different proteins. The distribution of these proteins varies along the length of a chromosome depending on the type of cell and this phenomenon is called 'epigenetics', literally meaning 'above the DNA'. Epigenetic analysis is the study of how proteins and other molecules can change the activity of a gene without changing the DNA sequence. All of our cells use epigenetic changes to help control how they grow and develop. Evidence suggests a direct link between diet and environmental influences on our epigenetic profile. Recent research has traced the origins of many of the health problems of adult life back to the earliest periods of development _ to the time spent in the womb and the first few years of life. If we are born with a low birth weight, we are more likely to get sick later in life. Overwhelming evidence exists that the environment in the womb is critical for a healthy birth weight (and health in later life) and it is thought that epigenetics may be the missing link between this environment, low birth weight, and therefore health in later life. In addition, mounting evidence supports a general link between epigenetic de-regulation and predisposition to disease. However, the timing and the overall contribution of environmental- genetic influences to the establishment of faulty epigenetic markings remain largely unknown. Twins are the best model to study this link as they share similar (but not identical environments) and some share identical genetic makeup. Using twins, Dr Jeffrey Craig and his team will investigate the factors in the prenatal environment that modify specific cells, leading to low birth weight and increase disease risk later in life. They predict that this occurs via specific changes in gene activity caused by epigenetic disruption.