“We must look at the influence of many genes and many

lifestyle choices, and importantly how they interact with each other”

Therefore we wanted to ask firstly, if the variation in ADrB2 affects fat storage, secondly, if exercise affects fat storage and thirdly, if they both do affect fat storage, does activity affect it differently in people with different versions of ADrB2. The short answer to these questions is yes, but apparently only in men.

We know that DNA sequence variation in this gene affects weight because groups of males carrying different combinations of variants have average weight differences of up to 5kg. Activity levels also have an effect as active males carry 2.4 kg less weight than their sedentary counterparts. However, when we look at the effect of activity within the gene variant groups we find that those with two copies of the variant who are active carry 2.8 kg less weight than those with two copies of the variant who are sedentary. However, those with two conventional copies and who are active carry 1.8 kg MOrE weight than those with two conventional copies who are sedentary.

This paradoxical result is most likely related to the anabolic effects of this gene with the extra weight being made up by muscle bulk rather than fat. However, it clearly demonstrates that exercise affects different people in different ways and that by understanding the interaction between genetics and exercise we might be able to predict who will benefit in what way from which types of exercise. It may be that some clients really do exercise in between session and don’t lose weight, although of course they are still gaining fitness and all the associated benefits.

This area of research is in its infancy but will undoubtedly end up having consequences for fitness training and weight loss in the future. In the mean time, an empirical approach should be adopted, working out what is best for each individual by trial and error, whilst accepting that one size very rarely fits all.

Neel, J. V. (1962). “Diabetes mellitus: a “thrifty” genotype rendered detrimental by “progress”?” Am J Hum Genet 14: 353-62.

THE AUTHOR

Dr Colin Moran has a degree in genetics from Glasgow University and PhD in the genetics of fruit fly sexual behaviour from Leicester University. However, a life-long interest in sport (from table tennis to judo) meant, seven years ago when offered the chance to join a lab working on the genetics of athletic performance and obesity, he jumped at it.

ANSWER THE FOLLOWING QUESTIONS ONLINE TO EARN CPD POINTS

Please login to the members area of the REPs website to give your answers

Q1 Q2 Q3 26

What is the name of the theory of good gene variants and bad gene variants? Is it:

a. The Thirsty Gene Hypothesis b. The Thrifty Gene Hypothesis c. The Hungry Gene Hypothesis

What are the two catecholamines in the blood that are raised by exercise: a. Adrenaline and Noradrenaline b. Adrenaline and Novadrenaline c. Adrenaline and Noxadrenaline

What is the name of the gene that mediates these? Is it: a. ADRB1 b. ADRB2 c. ADRB3

NB. Do not attempt to answer the questions in the interactive version of this magazine

The rEPs Journal 2009;15(Dec):24-26