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Genetics

Does your DNA do it for you? How genes may influence performance at high altitude

DNA is divided up into chunks called genes and each gene provides the code strip for the manufacture of a body protein. Genes come in pairs and all humans share the same 25,000 or so pairs. However, small variations in these genes, so-called 'polymorphisms', can alter the function of the gene. For instance, some polymorphisms can make the gene work faster or slower.

It is these small variations which are responsible for making us all different from each other. They influence our height, weight, temperament, how fast we run and also how well we respond to some diseases.

The Caudwell Xtreme Everest team hope to identify polymorphisms which are associated with a particularly good bodily response to low oxygen levels, to help understand why some patients survive very low oxygen delivery to their cells. Poor oxygen delivery is a common problem affecting adults who develop heart and lung disease and babies born with these diseases, such as cystic fibrosis.

In particular the team are looking at the ACE gene, the first gene linked to human fitness discovered by Hugh Montgomery in 1998. The same gene may be involved in aiding survival at very low oxygen levels.

The team hopes to analyse the DNA of populations dwelling at a range of altitudes. Over the years, natural selection will have applied to those dwelling at high altitude, making the best genes for survival in low oxygen environments more common there than in the lower valleys.

The team also hopes to obtain DNA from both elite mountaineers and those who have succeeded in climbing Everest. More than a thousand people have climbed Everest and the Caudwell Xtreme Everest team hopes to trace as many of them as possible with the aim of building a DNA database for this purpose. The assumption is that those with the best genes for low oxygen will have climbed more successfully, but this has never before been shown.

Finally, the Caudwell Xtreme Everest team have sampled the DNA of volunteers taking part in normal exercise tests whilst breathing low oxygen levels. Again, they hope to identify the genes which are associated with the best response.

DNA is obtained using mouth swabs which will either be taken directly from the person or indirectly by sending people kits to perform their own mouth swabs which can be sent back in an envelope.