A family consists of two parents and their five children and the pedigree chart below shows the inheritance of the trait colour blindness in them.

(a) Who is colour blind in the parents - the Father or the Mother?

(b) How many daughters and how many sons have been born in the family?

(c) What does the child 1 indicate about this trait?

(d) On which chromosome is the gene of this trait located?

(e) Name one other trait in humans which follows the similar pattern of inheritance.

(a) The given diagram showing inheritance of colour blindness. In this chart, males are shown by squares and females are circle. Hollow symbols represent the normal people and solid symbol represent the character being traced.

Thus, father is colour blind (solid symbol) and mother is normal (hollow symbol).

(b) In the pedigree chart, males are shown by squares and females are a circle. Of the five children born, three are daughters and two are sons.

(c) In the pedigree chart, the circle shows the female and solid represents the usually expressed character (colour blindness). Thus, the child 1 (daughter) is colour blind.

(d) Colour blindness is the inability of a person to distinguish red, green or both the colours from the other colours. It is an X-linked disease in humans. The gene responsible for this trait located on the X chromosome.

(e) Haemophilia like colour blindness is also caused by a recessive allele present on the X chromosome.