>> |
Dr. Grissom
!9GXd8p7Kds
File :-(, x)
Yes there have been many genetics studies from the 1940-1960's with different Drosophila species, mainly Drosophila melanogaster. Several of those tests produced some very strange results.
Depending on your definition of a species, many new "species" were created in that time period. If you believe "a population of isolated reproducing individuals" is a species, some of the mutations that were bred out by scientists involved mating behavior/mating preferential/sex organs and so on. Strains were artificially selected to the point that they would no longer mate with the original wild type Drosophila. In this sense they were "new" species because they only bred with the highly inbred relatives that shared the same odd mutation. However, many of these had such extreme malformities that they would never survive in the wild.
An example of this is the image, called ultrabithorax, a mutation that resulted in the 3rd thoracic segment to be replaced by a duplicate of the 2nd. It is estimated that about 100 million years ago, flies lost their second pair of wings.
http://en.wikipedia.org/wiki/Hox_genes
Another good example of evolution we have actively witnessed in the lab is P element, a transposon that appeared in a D melanogaster lab mid 20th century, and has since spread to all known wild populations of D. melanogaster. Though, the wiki article does not read easy....
http://en.wikipedia.org/wiki/P_element
|