• evolution;
  • gene-nutrient interactions;
  • nutrient availablility;
  • nutritional requirements

Nutritional requirements are not the same for all individuals. While there is generally a common requirement for the types of nutrients needed for survival, the quantities needed vary. In several instances, the differences in nutrient requirements can be attributed to specific genetic differences among individuals. When higher nutrient needs associated with certain genotypes are not met, there will be selection against those genotypes in the population. When these needs are met, the selection against such genotypes will be lifted and the alleles that confer high nutrient requirements can persist in the population. In cases where these alleles confer some selective advantage, high levels of the required nutrient can actually lead to an expanded frequency of those alleles in a population. In such cases, nutrient availability can provide a selective pressure that drives genotypic shifts in a population. Some of the data demonstrating the potential of nutrient levels to affect genetic evolution of a population are reviewed here.