In the second set of parallel sessions
on day one was the session on epigenetics.
Marcus Pembrey provided an introduction to the field of
epigenetics. He outlined a number of
epigenetic mechanisms which are associated with regulating gene expression, including
DNA methylation, histone modification and regulation by micro RNA. DNA methylation involves the addition of a
methyl group to certain parts of DNA.
Where this occurs in gene promoter regions, it has the effect of
silencing gene expression.
While it was always assumed that
there were some epigenetic mechanisms involved in cell development, a recent
advance has been in linking epigenetic modifications to environmental factors. In particular, Marcus pointed to a number of
studies which demonstrate how epigenetic markers are affected by early life
environment and early life socio-economic position.
John Dupré discussed
the enduring nature of epigenetic changes, including the methods of epigenetic
heritability and their impact on evolution.
The nature-nurture distinction has perhaps outlived its usefulness as
the interrelationship of the inherited and the experienced becomes more evident. Epigenetics seems to rule out the
gene-centred determinism that underlies some neo-Darwinist accounts of evolution.
Epigenetic mechanisms point to a mode of inheritance involving genetic,
epigenetic and cultural elements.
There is debate surrounding the mechanism of epigenetic
inheritance. Some evidence suggests that
that epigenetic changes may be heritable during cell division, but this is
controversial. Other inheritance
mechanisms may involve new exposure to environmental factors which bring about
epigenetic change with each generation. This appears to have been the case in
studies of rat maternal grooming patterns.
Sometimes discussion of epigenetics induces claims of
neo-Lamarckism, but John highlights that while epigenetic inheritance does
suggest the inheritance of acquired characteristics, it does not claim
selective acquisition of adaptive characteristics.
Ilina Singh addressed
some of the social scientific questions arising as a result of emerging
epigenetic knowledge. As the influence
of environmental factors on development becomes clearer, there will be a
growing space for social scientists to add constructively to the investigation
of epigenetic causes of disease.
Increasingly, conditions affecting adults may be seen as
developmental disorders with their origins early in life. An ecobiodevelopmental approach may be
necessary to properly address the interrelatedness of genes and environment and
to identify the relevant actors.
