Final answer:
Epigenetic studies focus on heritable changes in gene expression without altering the DNA sequence, often due to environmental factors. Gene-environment interaction studies examine how both genetics and environmental influences combine to affect individual traits and behavior. While related, epigenetics specifically refers to phenotypical changes driven by gene expression's modulation.
Step-by-step explanation:
The difference between a study on epigenetics and a study on gene-environment interaction involves the focus on how genetic expressions are influenced and altered. Epigenetic studies center around the modifications that do not change the DNA sequence itself but affect how cells 'read' genes. This can lead to different phenotypes despite the same genotype. Factors such as lifestyle, environment, and experiences can cause these epigenetic changes, which can be heritable and influence health and disease risk in individuals and perhaps across generations.
On the other hand, studies on gene-environment interaction consider how genetic predispositions and environmental factors such as diet, stress, and exposure to toxins, combine to affect individual development and behavior. These studies often aim to understand the bidirectional relationship between one's genetic makeup and environmental influences, not necessarily limited to changes in gene expression profiles.
An example is the case of identical twins with the same genotype: they can develop different phenotypes over their lifetime as a result of epigenetic changes unique to their environmental interactions. In genetics and behavior, these studies are often distinguished from areas such as evolutionary psychology and behavioral genetics, which may include components related to epigenetic changes but also consider broader patterns of genetic influence.