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Elite mammalian divers such as the *** whale can hold their breath for well over an hour
while they hunt in the depths of the oceans while land mammals such as humans barely last
a couple of minutes underwater without gasping for air.
An international team led by Dr Michael Berenbrink at the University of Liverpool has now traced
the evolution of the oxygen binding protein myoglobin to shed new light on how diving
mammals survive for such long periods under water without breathing.
Myoglobin a protein that gives meat its red colour is present in especially high concentrations
in elite mammalian divers so high that the muscle is almost black in colour but until
now very little is known about how this molecular is adapted in champion divers. The team identified
the electric charge on the surface of the protein which increases in mammals that can
dive under water for longer periods of time.
By mapping this molecular signature onto the family tree of mammals the scientists were
able to reconstruct the muscle oxygen stores in the extinct ancestors of today's diving
mammals.
All the proteins tend to aggregate at high enough concentrations which may serious impair
their function. We think the high net charge on the surface of myoglobin of all mammalian
divers causes electro-repulsion like similar between two poles of two magnets and this
will critically allow much higher concentration of the oxygen storing protein in the muscles
of these divers.
We are really excited about this because it allows us to align the anatomical changes
that occur during the land to water transitions of mammals which their actual physiological
diving capacity of these animals.
The study also has wider implications for human health research.
This work improves our understanding of how organisms evolve to avoid the problems of
protein aggregation which is important for a number of human diseases.
The research not only reveals mechanisms behind one of the most extreme physiological adaptions
in the animal world but also sheds new light on the surprising evolution of one of the
best known proteins.