/sci/ - Science & Math

So, because I am colorblind I wondered why this little defect was not selected against and the gene gone extinct long ago. As I grew up I noticed how I relied on shape, shade and texture more than people with normal vision. I once bought 3 blue notebooks at the campus bookstore and found that because they had each been faded by the sun to a different degree I could tell them apart while no one else could.
I Learned that during WW2 they put guys with colorblindness in bomber aircraft because we are not fooled by camouflage like others. In fact they were so useful they took guys out of prison to serve and when they ran out of those tried to train dogs.
Imagine a hunting party made up of both types of eyes; very little is going to escape them.
Now consider how giantism and dwarfism are pretty common compared to other "defects". Suppose they have not disappeared because every now and then the environment changes enough to make them advantageous. If you already have the dwarf gene floating around when your species colonizes an island you are going to adapt a lot faster than some other species waiting around for the right mutation.
How many other defects or variations are just genes that remain because the species needs them now and then.

Your thoughts /sci/?