Eye Regulatory Genes (Evolutionary Ancient)

The development of the eye was once thought to be a result of many different species that developed light detection independently.  However recent studies have found that the genes regulating the formation of the eye are conserved for species as different as the fly and the mouse.  This suggests that the eye in the fly is related to the eye in the mouse and that they have the same evolutionary ancestor!  In fact the re gulatory gene in the mouse can turn on the eye gene in the fly.

When this regulatory gene is turned on in other parts of the body eyes are formed in those parts. In the following pictures show eyes where they shouldn't be and no eyes where they should be. The very red areas are the new eyes.  For example,

The leg

The antenna

If this gene is turned off, no eyes form

However, these eyes don’t do much if they are not connected to anything and while there is evidence that some of these oddly placed eyes do respond to light they cannot see.  For an eye to see other regulatory genes have to be turned on in light receptor cells that then stretch out to the vision brain cells in the back of the brain (occipital lobe).  This most likely happens because the brain produces chemicals that say to the axons (nerve wires) in the eye to come to them.  You might think of this like a really good perfume that only certain brain cells can smell but when they do they just have to reach out to find the brain cells that are making the perfume (chemical signals).

When  the eye cells smell the vision brain cell perfume then they send out axon projections which are guided to the eye by detecting the different vision brain cell perfume strength and moving toward the stronger smells (Just like teenagers at the smell of pizza).