Task

In humans, haemophilia is caused by a recessive X-linked gene (h) and albinism by a recessive autosomal gene (a). A woman with normal pigmentation and normal blood clotting had a haemophiliac father and an albino mother. She married a man with normal clotting and normal pigmentation whose mother is albino. 1) Describe the features of sex-linked inheritance (X and Y chromosomes, hemizygosity, criss-cross inheritance) and of autosomal recessive inheritance. 2) Determine the spouses’ genotypes with reasons, write the cross, gametes and Punnett square. 3) Calculate the probability of a haemophiliac son (among all children and among sons, %). 4) Calculate the probability of an albino child (%). 5) Calculate the probability of a child phenotypically healthy for both traits (%). 6) Calculate the probability of a daughter who is a carrier (heterozygous) for both genes (%). For each part, write out the law or method used (cross scheme, formulas, reasoning) and all calculations step by step.