A woman suffers from colour blindness and her husband does not. They have a son and a daughter. Which one of the following statements is most probably correct?
A woman suffers from colour blindness and her husband does not. They have a son and a daughter. Which one of the following statements is most probably correct?
The correct option is D Son suffers from colour blindness while the daughter does not suffer from it
Colour blindness is hereditary disorder which can be transferred from parents to children. It is a recessive X linked mutation. If a woman inherits a normal X chromosome in addition to the one which carries the mutation, she will not express the mutation. Males only have one X chromosome, they have no spare normal chromosome to override the chromosome which carries the mutation. So, a male with the defective allele will express the disease too.
If a mother is suffering from Red/green colour blindness, then she is homozygous, i.e. both the X chromosomes carry the defective gene. So, when she passes on the X chromosomes to children, they get a defective copy of that gene. Thus, the son becomes colour blind as he has only one defective X chromosome and daughter becomes carrier as she gets a good copy of X chromosome from the father.
Son suffers from colour blindness while the daughter does not suffer from it
Colour blindness is hereditary disorder which can be transferred from parents to children. It is a recessive X linked mutation. If a woman inherits a normal X chromosome in addition to the one which carries the mutation, she will not express the mutation. Males only have one X chromosome, they have no spare normal chromosome to override the chromosome which carries the mutation. So, a male with the defective allele will express the disease too.
If a mother is suffering from Red/green colour blindness, then she is homozygous, i.e. both the X chromosomes carry the defective gene. So, when she passes on the X chromosomes to children, they get a defective copy of that gene. Thus, the son becomes colour blind as he has only one defective X chromosome and daughter becomes carrier as she gets a good copy of X chromosome from the father.
