Question

A son with cystic fibrosis ( autosomal recessive) is born to a couple who appear to be normal? what are the chances that any child born to this couple will have cystic fibrosis

Answer 1

25 % is the answer

Answer 2

could you show me how you got it?

Answer 3

K. saikat would you please show me how you got that?

Answer 4

as it is autosomal recessive..let us take the gene responsible is 'C'..so parents genotype will be Cc as both of them are normal..now if we cross then the chances come CC, Cc, Cc and cc..only the offspring with genotype cc will have the disease..so chance is 1/4 i.e., 25%.