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The changes in the myoglobin molecule of diving mammals over 70 million years reflect a increasing molecular surface charge.  Allowing for the reconstruction of extinct species of diving mammals.  Myoglobin's  increasing surface charge counteracts the natural aggregating effects common in non-diving mammalian myoglobin and allows for higher concentrations of cellular myoglobin, and hence increased oxygen capacity.  

This same …globin aggregating effect carries over into human genetic hemoglobin diseases such as Sickle Cell anemia, which genetically predisposes an increase tendency to aggregate in hemoglobin molecules carrying the "sickling trait."  In our case, breath holding capacity was exchanged for protection from malaria.  Of course, since we're not diving mammals but are susceptible to malaria, our evolutionary path was the opposite of diving mammals.

It's an interesting story.

http://video.sciencemag.org/VideoLab/diving/#.Ub_ECeb9zBs.gmail

C
Charles Carlson
Senior Scientist | Teacher Institute

http://blogs.exploratorium.edu/whyintercept/
Twitter: @charliec53
email: [log in to unmask] 
Tel:   415-528-4319
Fax:  415-885-6011
exploratorium.edu
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