Two people of normal health have a child with hemophilia (sex-linked recessive)?
May 4th, 2009 | by Michael |
dwijesh91 asked:
What are the genotypes of both parents? Explain
What are the genotypes of both parents? Explain
3 Responses to “Two people of normal health have a child with hemophilia (sex-linked recessive)?”
By matahari on May 7, 2009 | Reply
The parents are heterozygous for hemophilia. In order for the child to have it, he/she would have to inherit 1 copy of the recessive gene from each parent, otherwise the trait would be masked by the non-hemophilia gene.
By Richard H on May 8, 2009 | Reply
Dad has X (normal) y
Mom has X (normal) X(hemophelia)
The child is a boy
the boy’s genotype is X (hemophelia) Y
By Science Chick 316 on May 11, 2009 | Reply
H=Hemophilia
n=Normal
Dad=Xn y
Mom=XH Xn
Unless you know that the dad is affected by the disease (in which case he probably wouldn’t be having a child), the faulty gene comes entirely from the mother. Since the Hemophilia gene is recessive the mother won’t have any symptoms of the disease. The problem is: 50% of this couples male children will have the disease, and 25% of their total children will have it, and 25% of the female children will be carriers.