Epigenetics: which statements are correct? One or more answers are possible.
- It modulates the expression of genes without modifying the DNA sequence.
- It directly modifies the sequence of the bee’s genome.
- It depends solely on hereditary factors, never on the environment.
- It can be reversible and influence the phenotype of the individual.
- It is always transmitted stably over several generations.
- It has no observable effect on development or behaviour.
Show answer
Correct answer: 1 + 4.
It modulates the expression of genes without modifying the DNA sequence, and it can be reversible while influencing the phenotype.
Why?
Epigenetics refers to mechanisms that modulate the use of genes without changing the DNA sequence. The genome remains the same, but certain genes can be expressed more or less depending on the context.
These mechanisms can influence the phenotype, that is, the observable characters: development, physiology, behaviour or role in the colony.
In the bee, the classic example is the differentiation between queen and worker: the same genetic basis can lead to very different forms and functions depending on the feeding, the development and the regulation of gene expression.
What to understand
Genetics concerns the DNA sequence. Epigenetics concerns rather the way in which this information is read, activated, silenced or modulated.
Saying that epigenetics is reversible is useful for understanding the difference from a genetic mutation, but one must remain cautious: some marks can be transient, others more lasting, depending on the tissues, the developmental stages and the environmental conditions.
Epigenetic mechanisms are not always transmitted stably over several generations. They can be influenced by the environment, the feeding, the age, the social role or the conditions of development.
Key points
Epigenetics does not modify the DNA sequence: it modifies the expression of genes.
It can influence the phenotype, hence the appearance, the physiology or the behaviour.
In the bee, it helps to understand how the same genetic heritage can produce very different castes and social roles.
Further reading
► Epigenetics conducts genetics