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May 18, 2010, 11:31 am

DNA change for the high life!

Tibetans never get "mountain sickness"... their DNA holds a clue to healthy living at high altitudes.

What was discovered?

Two changes in the gene for haemoglobin can help the people of Tibet cope with living at high altitude.

Haemoglobin is the protein in red blood cells which carries oxygen around the body. 

Without oxygen our cells would not be able to make enough ATP as an energy source for all the processes needed to keep us alive, so having haemoglobin with two changes (mutations) that can capture oxygen more efficiently where it is scarce, like up a mountain, is certainly good for the people who live there!

But not all people living at high altitude for many generations have the two mutations - for example, the haemoglobin gene of indigenous people of the Andes do not!

How?

By sequencing the DNA of a gene, the nucleotides which give the instructions for each amino acid making up the protein can be found.  

Comparing the sequences of DNA from people who live at high altitude or at sea level, important changes in the DNA can be found.

The next step is to understand how these changes in the DNA alter the amino acids of haemoglobin and why these changes help oxygen to bind tighter to the haemoglobin.

Why is it important?

The changes in the haemoglobin molecule of Tibetans help it to deliver oxygen efficiently in conditions where there is insufficient oxygen without increasing the number of red blood cells to dangerous levels.

Understanding how this happens could help doctors develop methods or drugs to treat people anywhere in the world who suffer from serious heart or lung diseases.

And of course it could throw light on new ways to help mountaineers or travellers who suffer mountain sickness.