The Diary of Pelly D by L.J. Aldington

On a different planet in the not too distant future, dna testing has separated the population in three groups based on their supposed evolutionary status. The Atsumisi (red) are considered the most advanced. They have a gene expression no other group has though no one knows what the advantage of having it might be. Manizzi (blue) are second. They have the gene but it is inactive. Galrezi (green) are without the gene and considered inferior though the possess great artistic ability the others lack. I wonder if shedding the gene really makes Galrezi superior. Maybe the authorities have it backwards because they do not want to be of the inferior class.
In any case it doesn't take long for authorities to start deporting Galrezi to work on water projects elsewhere. Those who go seem to just cease to exist. Then Galrezi are blamed for water shortages at home, war that isn't fully explained and for protest against the government and are "punished" with curfews and limits to their freedom. The reader learns all this from a diary left behind by one girl who had fallen on hard times after being labeled Galrezi. The diary is found after the final clearance of the area in which the last of the Galrezi once lived. The worker assigned to help with the clearing and eventual rebuilding of the area takes risks by keeping and reading it. It is through him that we learn much of what happened to Galrezi, Pelly and her family - but not all. Is it possible that gene mapping could lead us to another massive genocide like the Jewish Holocaust? Will we ever learn to be truly tolerant? CHERRY HEAVEN is a companion to this novel for teens.