Genetic Diversity

Genetic diversity refers to a healthy and diverse gene pool for a specific species of either a plant or an animal. The term is also used to refer to the diversity of genetic material within an individual, a population, or an ecosystem. The latter is also and most often referred to as biodiversity (or biological diversity) and inevitably embraces all the levels of genetic diversity—namely genetic, species, community and ecosystem—needed to maintain the comprehensive health of an ecosystem.

Genetic diversity is important when discussing both micro- and macro-organisms. In terms of the former, public health intervention strategies to track the global spread of disease pathogens, to develop diagnostics and vaccines, and to understand the emergence of new and drug resistant vaccines [Page 741]are founded upon the insights provided by research into the genetic diversity of pathogens.

Individuals, species, and entire ecosystems are advantaged by high genetic diversity via their increased capacity to adapt. Such capacity is often referred to as resilience. Ecosystems, which are made up of many interacting species, are healthiest when species interactions are maximized or all relevant niches are filled. High genetic diversity is correlated with a healthy species and/or ecosystem in that it provides that species and/or ecosystem with the necessary materials for adaptation to environmental and physiological perturbations. Low genetic diversity is considered problematic in that it limits a specie's and/or ecosystem's ability to respond to changes.

A well known example of the dangers of low genetic diversity is the devastation that ensued when a virus infected and killed much of the potato crop of Ireland resulting in the 19th century Irish potato famine. Had there been more of a genetically diverse potato cultivation, it could have potentially averted this famine by allowing varieties resistant to the virus to continue. On an ecosystem level low genetic diversity is common in extreme environments (high latitude/altitude, overly dry) where only species with particular adaptations to those stressful environmental conditions can thrive. As global warming changes the temperature and water regimes of these areas, researchers are concerned about the native species' ability to adapt.

Biocomplexity is another term that is critical to understanding the role that genetic diversity plays in human-environment interactions, and refers to the multitude of biological, chemical, physical, behavioral, and social interactions that affect, sustain, or are modified by plants, animals and humans. Because all systems associated with life, both biological and human-made, interact and interdepend, they all exhibit biocomplexity.