University of Bristol
Wellcome Trust
Recommended by:
Society of Biology
PEEP for Physics & Ethics at GCSE


Epigeneticists study the action of the environment upon genetic inheritance. If you know a pair of identical twins well, you will have little difficulty in distinguishing them. But their DNA is the same, so what accounts for the differences between them?

The human genome project sequenced the DNA, but this map is only the first - albeit a major – step in understanding the complexities of inheritance, and what predisposes some people to particular diseases. It is now believed that a whole series of genetic switches operate on the genome, causing genes to either “switch on” and code for their protein, or “switch off” and remain apparently functionless. The new area of research is into increasing our understanding of what actually causes these switches to be thrown.

The science of genetics is poised to make a huge leap forward. One contentious idea is that environmental factors experienced by our ancestors may affect us decades later. This means that genes may have a “memory”, and that what someone does do in their lifetime may have an impact on the generations to come.


Question: some people argue that they know the risks of smoking, but they want to smoke and should be allowed to do so, providing it does not affect others. In the light of what research in epigenetics might tell us, do you think that that the smoker’s argument is right?

Task: you can understand more of the evidence for the argument for genes having a memory by visiting

 this BBC website and listing the evidence for it claimed by the various scientists.

Thought Experiment: If it is possible that the action of genes is affected by environmental conditions, what ethical issues does this raise:

  1. for peoples’ lifestyles?
  2. for the medical and healthcare professions?
  3. For people thinking about having children?


Next: Genetic Technology


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