`Individual genetic differences outweigh differences in populations'

STEPHEN M ROTH is an exercise physiologist who heads the Functional Genomics Laboratory at the University of Maryland, USA. In an e-mail interview he talks about the genetics of sports. Excerpts

Can genes pin down sports performance, and to what extent?

Genes can't "pin" down sports performance performance is far too complex. We know that genes do contribute to sports performance, potentially contributing to physical traits such as strength, coordination, endurance, and mental traits such as focus, competitive drive. But these traits are also influenced by environmental factors (training, coaching, equipment). So successful elite athletes are very likely successful due to both some unique genetic contributions as well as supportive environmental conditions.

Are performance genes more concentrated in certain populations?

This is one of the trickiest questions in the area of sport performance. Is there something unique to Jamaicans that makes them such strong sprinters? Why are Norwegians such strong skiers? While this is possible, there are also cultural and environmental differences that correlate with different populations that make these associations very challenging to understand. There are certainly some gene variations that are more frequently found in different populations, but there are so many genes that contribute to different traits that it's hard to imagine that certain populations are at distinct disadvantages in most sports. As such, it appears that individual genetic differences do outweigh differences that might be observed in populations.

How real is the threat of gene doping?

I don't believe this is a significant threat at present only because gene therapy itself needs to be solidified as a medical technique before it can "spread" to performance realms. Where there is a gene therapy product in an area that might be related to physical performance (e.g., gene therapy for muscle mass or strength) then it could certainly be used for performance enhancement. But most gene therapy trials show side effects, making this very risky for use in athletes until they are more successful in therapeutic scenarios. That doesn't mean it won't happen. We know that athletes and coaches push the envelope of safety with other illegal performance enhancement substances, but I don't believe this is a serious concern in 2016.