The Concept of Epigenetics: Expression of Genes and Environmental Influences

Introduction

Epigenetics refers to modifications made to genes, which do not alter the DNA sequence but affect how the genes are expressed. While the concept of epigenetics was rejected in the past, recent studies have indicated that environmental factors can indeed influence gene expression and even be passed down to offspring. This blogpost delves into the topic of epigenetics, using examples of historical events and scientific research to illustrate its significance.

The discovery of diverse DNA methylation patterns in genetically identical female worker bees performing different roles, nursing or foraging, indicates that gene expression can be influenced by behavior.

Environmental Influences on Gene Expression

The Hongerwinter in Holland, the Biafra famine in Nigeria, and the Great Chinese Famine are all examples of extreme environmental factors that affected the health of the people who lived through them. Studies have shown that children conceived during these periods exhibited abnormal patterns of methylation, which turned on or off genes associated with various disorders. For instance, individuals prenatally exposed to maternal food deprivation during the Great Chinese Famine showed an increased risk of schizophrenia. Similarly, the children conceived during the Hongerwinter were at a greater risk of obesity, heart disease, diabetes, and hypertension.

Understanding Gene Expression and Epigenetics

DNA contains genetic information that determines the traits of an organism. The genetic information is translated into the manufacture of proteins and RNA molecules, which are responsible for the outward or physical traits of an individual. Epigenetics, on the other hand, refers to changes in the genes that do not involve alterations to the DNA sequence. For example, the addition of methyl groups to the DNA backbone interferes with its ability to transcribe messages to RNA. Such epigenetic changes have been observed in some cancers.

Epigenetics and Behavior

Andrew Feinberg's research on worker bees provides insight into the link between epigenetics and behavior. Although worker bees within a hive share identical genetic sequences, those with different behavioral patterns have distinct DNA methylation patterns. Interestingly, when nurse bees were removed from the hive, the foragers took over their roles and exhibited the methylation patterns of the nurse bees. This suggests that epigenetic marks are reversible and can be linked to behavior.

Conclusion

The concept of epigenetics challenges the traditional view that traits are solely determined by genetic information. Studies have shown that environmental factors can affect gene expression and even be passed down to future generations. Epigenetics provides insight into the complexities of gene expression and the interplay between genetic information and environmental factors.