POPULATION GENETICS

Every individual within a population (interbreeding organisms) of a certain species has a set number of genes. BUT the possible combinations of these genes for potential offspring is exponential. If a population of straight-haired mice were suddenly joined by a population of curly-haired mice, the combinations for the gene for hair shape increases. After a generation has passed, you might observe a population of straight-haired, curly-haired and wavy haired mice. You might observe that all the straight-haired mice die during a cold winter because their fur did not keep them as warm as the wavy and curly haired mices' fur did. The addition of this new expression for hair-shape in the genes contributed by the curly-haired mice changes the gene pool of the mice population. A gene pool is best described as all the genes of all the individuals in a population.

New traits in a population may arise through the following processes:

1) MUTATIONS--change in the DNA code that produces proteins which produce the genetic features;
2) MIGRATION or GENE FLOW--the movement of organisms out of the population (emigration) reducing the population's size and the selection of available genes OR the movement of new organisms into the population (immigration) increasing the population's size and the selection of available genes;
3) GENETIC DRIFT--the random loss of genes due to chance events...for example, the population is reduced in size because the many group members were killed during a flood; hunting of the elephant seal between 1820 and 1880 nearly wipped out the entire population
4) NON-RANDOM MATING--when organisms within a population select their mate based on exhibited behaviors, bright colors, dominance in the group etc...
5) SELECTION--a process which usually depend on the environmental conditions and involves selecting for certain traits and against others within a population of organisms

With today's biotechnology, new traits can be added to organisms. It is possible to add a gene that produces "insulin" (a hormone to lower blood sugar levels in humans) to a bacteria cell. When this gene is added to the DNA of a bacterium, the bacterium produces human insulin. What possible impact could this technology have on the gene pool of entire populations.