A normal visioned woman, whose father is colour blind, marries a normal visioned man. What would be the probability of her sons and daughters to be colour blind? Explain with the help of a pedigree chart.
The pedigree analysis shown below depicts the colour blindness in offspring:
About 8% of the males are colour blind, while only 0.5% of the females are colour blind. This is because only one X-chromosome is present in males. If that one X-chromosome carries the defect, the boy will suffer from colour blindness. But in females, there are two X chromosomes which help in the compensation of deficiency in one of the chromosomes. Thus, females are generally carriers of the disease and rarely the sufferer.