Reverse Fruit Fly Evolution
12 January 2009
Fruit flies (Drosophila melanogaster) have long been a favorite of scientists for observing mutations and natural selection because of their short lifespan and rapid reproductive cycle. The results were published from a study that started over thirty years ago with breeding fruit flies in a variety of environments that would cause 'unnatural' selection (such as starvation and longer life cycles) and force certain types to die and others to survive. Now they have taken some of the offspring from 50 later generations and caused a successful reverting of some of the original characteristics; however, were not able to revert all the characteristics.
This is being called evolution happening in reverse, but what really is happening? When the fruit fly was created it had all the genetic information to survive in several different environments. When they starved them, some survived and others died. When the exposed them to different climates, some survived and others died. In the end natural selection weeded out the weaker ones and allowed the more suitable ones to survive. THIS IS NOT EVOLUTION.
The original flies were genetically superior because they contained all the information needed to make all the better adapted and worse adapted flies. After 50 generations some of this information was irretrievably lost and some just went dormant. When brought back to the original environment some traits returned but some did not. This is not because the flies EVOLVED the ability back again, but it is because it was already there.
This experiment was a long expensive way to show that we successfully know how to take a perfectly good fly and over 50 generations make it genetically inferior to its parents.
- Natural selection only selects from already existing information.
- These flies never gained any new information.
- Loss of information is not evolution.
http://www.igc.gulbenkian.pt/media/article/37
