Genetic Diversity
The genetic diversity of a population is the total number of different
characteristics within the population that individuals can inherit from their parents.
The greater the genetic diversity a population has, the better are its chances
of having the right characteristics for adapting to stresses its environment
may inflict. A plague, for example, could wipe out an entire population
that lacked enough diversity.
Bacteria change constantly. When a disease-causing bacterium changes to
attack a certain genetic variation within a species, the changed bacterium might
be virulent enough to kill all individuals with that gene type. Individuals with different
genes, however, might get sick but live and the population survive.
Diversity in humans
Humans, even in small populations, contain 86 % of the total diversity of our
species. "So, if everyone else on the Earth were to go extinct, leaving
only the people living on Sardinia, or Madagascar, or Vancouver Island, or New
Zealand ― only about 14 % of the genetic diversity of our species would be
lost," says geneticist Steve Mack of
Children's Hospital Oakland Research Institute (CHORI).
Plans for populating space
To maximize genetic diversity, we might consider screening pioneers and picking
those with different genes. Such diversity would help a small founding
population adapt to whatever they encounter. But
even with only about 85 % of total diversity, our populations have survived
everything Earth has thrown at us for at least two million years.
Further Reading:
Viable colony answer by Steve Mack, MadSci
(Answered 25 July 2009)
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