Genetics is the science of variation in humans and animals. It examines the nature and extent of inherited traits, as a branch of the broader science of biology. The term genetics was coined in 1905; the science was rooted in the work of biologist Charles Darwin (1809–1882), which he conducted on heredity in the mid-nineteenth century.

Genetics is a branch of scientific research that has moved with remarkable speed in the past 100 years. In 1908, the first breakthrough discovery that was entirely founded upon genetic principles was the understanding of the role played by genetic defects in inherited disease.

The era of modern genetics began in 1977, when the components of the human genetic code were first identified. Deoxyribonucleic acid, best known by its acronym, DNA, was definitively identified as the molecular grouping that carried all human hereditary material, either in the nucleus of every cell in the human body, or in the mitochondria, the cellular powerhouse where energy for physical movement and function is produced. The discovery of the extreme intricacies that

Better understanding of the role of genetics in human development has lead to more accurate assessments of the importance of genetics relative to training and athletic success.
lay at the heart of the DNA sequence became itself a distinct branch of molecular biology.

The DNA sequence was further determined to be stored as a code within each cell; more than 99% of all three billion DNA bases within a human cell are the same in all people, with less than 1% of the DNA underlying human physical and mental distinctions. It was also discovered that DNA can replicate itself.

It is against this backdrop of the science of the function of the DNA molecule that the human gene can be understood. Genes are the basic units of human heredity, passed from parent to child. A gene is composed of pieces of DNA. Each gene constitutes an instructional guide for the body in the manufacture of protein molecules, the building blocks necessary to the physical construction of the human body. There are two copies of each gene in every cell, one from each parent. A gene will remain in its original hereditary structure within the body, or it may become mutated, which represents a permanent alteration in its DNA structure.

In 1990, a massive scientific project was initiated by the U.S. Departments of Energy and Health, undertaking a comprehensive study of the entire gene collection in the human body, a structure referred to as a genome. The Human Genome Project, as this study was called, involved partners from numerous other countries, including England, France, China, and Canada. On its completion in April 2003, the Human Genome Project had successfully completed the rough work involved in the mapping of the three billion pairs of the DNA sequence, as well as that in relation to the between 20,000 to 25,000 human genes.

The explosive growth in the amount of knowledge gained through the scientific examination of human genetics has been reflected in a number of aspects to sports science. Better understanding of the role of genetics in human development has lead to more accurate assessments of the importance of genetics relative to training in athletic success, the "nature versus nurture" debate. Genetic research has tended to confirm that while certain types of people have a genetic predisposition to success in certain types of sport, that favorable genetic makeup is never a guarantee that the athlete will achieve success. The genetic structure is believed to be approximately 50% of the sports success equation, with the remaining components being training approaches, the general social environment, and intangibles such as mental drive and willingness to compete, neither of which is perceived as having a genetic basis.

The next great frontier in the context of genetics, ethics, and sport is gene doping. Gene doping is the concept of introducing an athletically favorable set of genes into an athlete to enhance an aspect of his or her existing performance capabilities. It is believed that gene doping would naturally focus on a limited number of traits in an elite athlete, such as increased upper body strength or oxygen uptake, as opposed to the genetic makeup of the entire body. Gene doping is an approach that is an extension of the experimental medical technique known as gene therapy, which is premised upon the notion that genes may be injected into a human body and either reverse or correct an illness or a disease that has a genetic basis. While there has been a number of encouraging results in the laboratory regarding gene therapy, the results concerning humans are inconclusive.

Gene doping is of particular concern to sports ethicists because the fact that successful gene doping trials have not been publicized does not mean that experimentation has not taken place. The ability of the national and international sport-governing bodies to detect the evidence of such scientific enhancements of performance through testing is often years behind the development of the illegal procedure, as was demonstrated by persistent gaps between the widespread use of illegal performance-enhancing substances and the results of testing for both anabolic steroids and the blood doping agent, erythropoietin (EPO). The World Anti-Doping Agency (WADA) has banned gene doping, without having any effective means to positively determine whether an athlete has engaged in such a procedure.

SEE ALSO Hormones; Juvenile obesity; Longevity; Obesity.