12 Genetics and Performance

• Deoxyribonucleic acid (DNA)


  A thread-like structure made of DNA that contains genetic information
• Chromosome


  Double helix structure that contains genetic information
• Each cell carries 2 pairs of 23 chromosomes (46 in total), except gametes (sex cells), which only have one pair of 23
• DNA contains 4 different bases: adenine, thymine, cytosine, guanine</b>
• Gene


  A section of a chromosome that codes for proteins
• Phenotype


  The physical, observable characteristic or what it looks like
• Protein


  Large molecules composed of amino acids that are required for the structure, function and regulation of body cells, tissues and organs
• Allele


  Genes of an organism
• Genotype


  The genes of an organism in terms of the alleles present
• Amino acid


  The building blocks of proteins
• Replication


  For growth and repair
• Mitosis


  Cells divide and the chromosome number is halved
• Meiosis


  Produces gametes for reproduction
• Genes are inherited from parents via their gametes, 50% from mother and 50% from father
• Many millions of combinations of these genes are possible
• Some phenotypes are expressed completely from genes, e.g. eye colour, gender
• Some phenotypes are expressed from a combination of the genes and the environment, e.g. height, VO2 Max
• Regulation


  Genes can be switched on or off, depending on internal and external factors
• Genes determine each characteristic, so it is unlikely that a single genetic element is responsible for strong athletic performance
• Genetic and environmental factors both influence athletic performance
• Genetic factors influencing athletic performance

  • Height
  • Muscle fibre type
  • Anaerobic threshold
  • Lung capacity
  • Flexibility
• Environmental factors influencing athletic performance

  • Physical training
  • Nutrition
  • Technological aids
  • Climate
  • Psychological factors
• Genetics can provide an advantage and increase the potential ceiling that you may be able to reach, but you are only able to reach that ceiling with the proper environmental factors
• Both genetic and environmental factors can separate an elite athlete from a regular athlete
• Genetic characteristics influencing performance may not be permanent as genes can be switched on and off
• Potential benefits of genetic screening

  • Can identify possible connective tissue issues
  • Can indicate if an unborn child has a genetic mutation
  • Can show early indicators of athletic ability in a child
• Potential implications of genetic screening

  • Individuals may be discriminated against during recruitment
  • Tests are not 100% accurate
  • Could lead to gene doping in the future
  • Could prevent late developing athletes
• Genetic screening only focuses on genetics and not the environment