In the article, Judge allows suit in birth of sons with cystic
fibrosis, Heather and Jason Blouin discover that the two youngest
of their three boys have cystic fibrosis symptoms. After some gene
testing, the parents find that they (the parents) are both
heterozygous for the CFTR gene that causes the disease. Both of
them have inherited one dominant allele and one recessive allele.
For an autosomal recessive disease like cystic fibrosis, a
heterozygous person is called a “carrier” because they carry a
hidden recessive allele that can be passed on to their children.
Question 4: What percentage of Heather’s egg cells that she
produces during her lifetime will carry the recessive (cftr) allele
and the X chromosome? Support your answer with an explanation of
how you arrived at the number.