Genetic Variations Essay, Research Paper
Charles 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 hosts blood cells in a weeks time. The pathogen multiplies in each blood cell and is then released to invade cells. The disease is widespread in Africa, especially among children. There are many in Africa who don’t die from malaria. Why?
When a certain acid is added to the blood cells, the cells take on a sickle shape and collect to form rod-like structures. The rods then stop the Malaria parasite from invading the blood cells. A genetic mutation in the hemoglobin gene can cause red blood cells to sickle without the help of an acid. In Senegal there are 15%-20% that carry the mutated gene. 20% of the total population in Africa carry the gene. Why doesn’t everyone carry the gene?
You can never have too much of a good thing. When two people both carry the gene and produce offspring, there is a 1 in four chance of one of the offspring carrying both genes. When this happens, a disease known as sickle cell anemia occurs.
Sickle cell anemia can cause excruciating pain to those who have it. The blood cells will sickle when the body experiences physical exertion and will also occur even when there is no Malaria parasite present in the body. The sickled cells build up in the blood stream and cause pain. Though there are drugs available to help ease the pain, there is no cure.
Humans are 99% identical to chimps. We vary in bone structure, skin, blood type, hair, and other organs and tissues. It doesn’t take much to change how an animal looks when it comes to mutations. Scientists wonder – could a mutation in a single gene have caused humans to take such a leap from the chimp?
These are just a few examples of how genetic variations form the planet on which we live. Other examples include the family of ruminants and how they are able to digest lysazine, the mutations caused by X-ray radiation in the fruit fly, and countless other experiments scientists perform to get a better understanding of how mutations affect the world around us. Each organism on this planet had origins from mistakes. Mother Nature discards the failures of genetic variations, and continues with the success, forming a world rich in diversity.