Genetic variations
Genetic variationsCharles Darwin stated that over time life could change so much so that new species are formed from a single species. But Darwin did not know where these mutations occurred. His theory could explain how humans and chimps are so alike yet different. Are we all just accidents of creation caused by mutations?
Genetic mutations occur in the DNA of an organism. They can be influenced by environment or may occur during mitosis or meiosis. Mutations have been shaping life since it began and is the cause for genetic variations from one generation of a species to the next. Without mutations, life on this planet would not be possible. The ability to change is needed for life to flourish.
Hawaii's state bird, the nene is in danger of extinction. Once 50,000 nenes inhabited the islands. Now there are less than 200. The sugar cane fields in Hawaii became the breeding grounds for rats. Farmers released mongooses to kill the rats. They also began to eat the nene chicks and eggs. Roy Blackshire runs a program that places captive born nenes into the wild. This program, once a success, is now causing chaos in the nene population.
A single pair of nenes were taken from the wild and bred in captivity. Later two more birds were added. The chicks were released into the wild and the program continued. Though there are several dozen nenes released from captivity, there is still little increase in the wild population. The inbreeding between birds is not allowing for any genetic diversity to occur between them. It is also causing captive-bred birds to lay eggs that don't produce chicks.
Scientists collect blood samples from nenes in the area, searching for a descendant of the wild nenes. The blood is then sent to a DNA lab for fingerprinting. It shows that the captive breeding is actually harming the bird population. As expected, today's nenes have far less genetic variation than their descendants.
A mutation in the 1 of the 500 letters of the hemoglobin gene has proved to be very helpful to those in Africa who carry it. Malaria is a very deadly disease, one of the 3 deadliest in the world. Malaria is passed to humans by the anopheles mosquito, and can decimate all of the...
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