Vitamin Dresistant rickets is an Xlinked dominant disorder R

Vitamin D-resistant rickets is an X-linked dominant disorder. Red hair is an autosomal recessive trait. Mary has rickets, which she inherited from her father, her mother does not have the disorder. Mary also has red hair. Her husband Tom does not have rickets or red hair, but his mother had red hair. What is the chance that a child of Mary and Tom will be a boy that has both rickets and red hair?

Solution

Red hair is an autosomal recessive trait. Mary has red hair, her husband Tom does not have red hair. Autosomal recessive disorder carry two copies of an abnormal genes in order for the disease or trait to develop. Because Tom doesn\'t have that gene, so red hair will not transferred in to thier offspring.

Vitamin D-resistant rickets is an X-linked dominant disorder. Females has two X chromosomes and mutation occurs in one of the two X chromosomes is sufficient to cause the disorder, and it will be tranferred to thier son, so thier boy will be affected from rickets and will remain unaffected from red hair.