Mouse Eyed Fly

How could genes from a mouse cause a fly to grow eyes in odd places?

In 1915, the absence of compound eyes was first described, with the end result of the term “eyeless gene”. The eyeless gene is widely believed to be the “master switch” or genetic code for eye growth and development, because it is a common feature shared by most mammals and insects including mice and flies. Even though the eyes themselves are different, the gene that gives the message to grow an eye is very similar.

Swiss researchers found that by switching on the Pax6 gene (the scientific name for the above mentioned master switch that controls eye growth) in other parts of the fly, an eye would grow in that area. To do this, they had to change the promoter sequence so the mouse gene would be compatible in the fly. After changing the promoter sequence which initiates cell transcription, the transcription factor tells the fly to grow an eye right there – not to grow a mouse eye. The homeobox gene encodes transcription factors that switch on multiple other genes. Some of the implications of this finding are that genetic control mechanisms are more related than previously thought, even though mammals (mice) and insects (flies) have evolved separately for more than 500 million years.

The reason that this is important is that we now know that there was a common ancestor that had the first eyes. These eyes contained the pax6 gene, which has been passed down ever since. This means that there is a chance that other master switches have been passed down, and can provide a treatment for people whose “switches” are turned off, as long as they are diagnosed and treated before birth. This can keep people from being blind or having physical birth defects like spina bifidia or cerebral palsy. Damage to the pax6 gene caused eye mutations, or defects. If more research is done in the field of master switch genes, treatment before birth could completely prevent the defect, and be much cheaper. Because of...