Summary of IUPS 2013 Lecture
This account was posted by a graduate student at the
Congress on the same day as the opening ceremony and
lecture: 21st July 2013:
http://scienceasadestiny.blogspot.co.uk/2013/07/iups-2013-sir-paul-nurse-and-denis-noble.html
"Physiology moves back onto centre stage: a new synthesis
with evolutionary biology"
Denis Noble CBE FRS. About: Eminent researcher in
cardio-vascular physiology, current president of the IUPS.
Key point: New insights in physiology are exploding the
traditional concepts of Neo-Darwinism evolutionary theory,
and opening up a new world of hereditary mechanisms.
"If physiology has moved off centre stage, it is coming back
with a vengeance".
"The genome is an organ of the cell, not a dictator. Control
is distributed".
Noble also described
how our very concept of a gene has changed and the classic
linear progression of DNA --> phenotype has been abandoned
in favour of a three way interaction between DNA, the
environment and the phenotype via a biological network. This
explains why knocking out genes rarely reveals their
function as the network can compensate for their loss. This
was demonstrated effectively by Hillenmeyer et al. who
showed that approximately 80 % of knock out gene mutations
in yeast are silent unless additional environmental
constraints are imposed.
Noble then moved on
to ask "Why should a physiologist be concerned with
evolutionary biology?". Traditional evolutionary views are
gene centred, yet physiological research is demonstrating
that organisms can "immune themselves from the genome".
Furthermore, information transmission is not a one-way
process as organisms can impose downward control onto DNA
through cell signalling, transcription factors and
epigenetic modification. An example of this is provided by
work on rats showing that regular grooming in early life
makes the mature adult less fearful - is grooming time
limited in colonies stressed by predation or starvation?
Another exciting illustration is the production of cross
species fish by placing a carp nucleus into an enucleated
cell from a goldfish. In the rare circumstances when this
produces an embryo, the skeletal configuration is
intermediate between the two, but much more similar to the
goldfish. Hence, information cannot be transmitted solely by
the DNA but must be influenced by maternal factors in the
egg cytoplasm. Work on the nematode worm
C. elegans
meanwhile, has revealed that epigenetic changes can be
incredibly robust. Here the inheritance of antiviral RNA
molecules was demonstrated for up to 100 generations, even
though the DNA template had been lost; inheritance had been
achieved through RNA polymerase amplification in the
cytoplasm. Our view of the DNA machinery should echo that of
Barbara McClintock, who viewed DNA as a highly sensitive
organ that can detect and respond to unexpected events.
Noble cited how genome reorganisation may also occur through
the lateral acquisition of new DNA material from unrelated
cells, such as the ingestion of the prokaryote cells which
became reduced to mitochondria and chloroplasts. The central
concept of this stimulating lecture was clear: the genome is
NOT isolated from the environment and furthermore, acquired
characteristics can be inherited. Perhaps Lamarck wasn't so
wrong after all.
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The MUSIC of Life: Biology Beyond the Genome ©Denis Noble |