how does the external environment of an organism can affect gene function.
http://www.nature.com/scitable/topicpage/environmental-influences-on-gene-expression-536
The external environment of an organism can affect gene function through a process called gene-environment interaction. This interaction refers to the interplay between genetic factors and external factors, such as diet, stress, toxins, temperature, and social interactions, among others.
Gene expression, which is the process of genes being "turned on" or "turned off," can be influenced by environmental stimuli. Here's an explanation of how the external environment can affect gene function:
1. Epigenetic modifications: The external environment can lead to changes in the chemical structure of DNA or its associated proteins. This results in epigenetic modifications that can either promote or suppress gene expression. For example, environmental factors like diet and exposure to toxins can cause DNA methylation or histone modifications, which can impact gene activity.
2. Gene regulation: The external environment can directly affect the regulation of genes. For instance, certain environmental cues or stressors can activate transcription factors - proteins that bind to specific regulatory regions of the DNA - which then initiate or inhibit gene expression.
3. Mutation and adaptation: Environmental factors, particularly those that cause DNA damage (e.g., radiation), can lead to genetic mutations. Mutations can alter the structure or function of genes, potentially impacting their expression or protein production. Organisms can adapt to their environment over generations through natural selection, which favors certain gene variants that confer a survival advantage.
4. Transgenerational effects: Some environmental factors can influence gene function across generations. Research indicates that certain epigenetic modifications may be passed from parents to offspring, leading to altered gene expression patterns in the offspring, even in the absence of direct exposure to the original environmental factor.
Understanding how the external environment affects gene function is a complex area of study. Researchers use various techniques, such as studying gene expression patterns, analyzing epigenetic modifications, and conducting experiments under controlled environmental conditions, to illuminate these interactions.