The Y chromosome does not cause color blindness. Colorblindness is a defective gene on the X chromosome. Females have 2 x chromosomes, thus one can serve as a backup for a defective gene. However, the Y chromosome in males is almost totally defective, thus does not have a backup.olorblindness is a defective gene on the X chromosome. Females have 2 x chromosomes, thus one can serve as a backup for a defective gene. However, the Y chromosome in males is almost totally defective, thus does not have a backup.
Kilwa Kisiwani (also known as Kilwa or Quiloa in Portuguese) is the best known of about 35 medieval trading communities located along the Swahili Coast of Africa.
'With one eye I saw the ever-present poverty, lack of plumbing, and constant energyâ¦ and with the other eye I saw joy and love': American photographer's touching pictures of world's largest slum. It's probably hard to imagine what life must be like in the slums of Africa. The Kibera slum in Nairobi is six hundred acres of mud and filth. It's not on any map because it's squatters camp - an illegal, forgotten city, yet at least one third of Nairobi lives here. Over the years the illegal slum has grown amongst the filth.