Video transcript: How diving mammals evolved underwater endurance

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June 2013

Video shows a computer generated sperm whale swimming underwater and then shows a human swimming in a pool, taking breaths often.

Elite mammalian divers such as the sperm 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.

Video shows various clips of the laboroatories at the University of Liverpool and Dr Berenbrink as he is being interviewed

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.

Video shows a computer generated Myoglobin protein, that is also shown in various clips later, spinning in 3D space. Different samples of meat show the different darknesses of red they have. The whale meat is the darkest.

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.

Video shows a 3D chart which measures evolutionary time of several mammals and demonstrates how myoglobin has increased in whales as opposed to cows and pigs

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.

Dr Michael Berenbrink, University of Liverpool:
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.

Video shows the evolutionary steps the dolphin has made over millions of years and how it's diving compacity has increased from 2 minutes to 88 minutes

The study also has wider implications for human health research.

Dr Michael Berenbrink, University of Liverpool:
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.