Haemophilia is a sex-linked recessive disease. Study the pedigree analysis given showing the inheritance of the disease in a family and answer the question that follows.
Write the possible genotype of the individual '2' and '5'.

Q. Haemophilia is a sex-linked recessive disease. Study the pedigree analysis given showing the inheritance of the disease in a family and answer the questions that follow.
Give the evidence from the analysis, which suggests that the disease is sex-linked and caused by a recessive allele.

Q. Three Mark Questions:
Haemophilia is sex-linked recessive disorder of humans. The pedigree chart given below shows the inheritance of haemophilia in one family. Study the pattern of inheritance and answer the questions given (a) Give all the possible genotypes of the members 4, 5 and 6 in the pedigree chart
(b) A blood test shows that the individual 14 is a carrier of haemophilia. The member numbered 15 has recently married numbered 14. What is the probability that their first child will be haemophilic male.

Q. Short / Long answer type questions.
Haemophilia is sex-linked recessive disorder of humans. The pedigree chart given ahead shows the inheritance of haemophilia in one family. Study the pattern of inheritance and answer the questions given.
(a) Give all the possible genotypes of the members 4, 5 and 6 in the pedigree chart,
(b) A blood test shows that the individual 14 is a carrier of hemophiliac. The member numbered 15 has recently married the member numbered 14. What is the probability that their first child will be a haemophiliac male?

Q. A pedigree chart of a family with an autosomal recessive disease Z is given. Assume that inheritance is Mendelian, and that all individuals with homozygous recessive genotype have the disease. Circles in the pedigree represent females and squares represent males. Filled shapes indicate affected individuals, while unfilled shapes indicate unaffected individuals. If J does not have the recessive allele, the probability that I is a 'carrier of disease Z' is?

Q. The figure given below shows a family pedigree (family tree) to show the inheritance of cystic fibrosis. [3 MARKS]



(a) Is the allele for cystic fibrosis dominant or recessive?
(b) State with reasons the genotype of individuals 1, 2 and 4.
(c) What are the possible genotypes of individuals 3 and 5?