A child is diagnosed with a rare genetic disease. Neither parents has this disease?
HMMMMM
The disorder was inherited because it is:
A dominant and carried by one parent
B. recessive and is carried by both parents
C. sex-linked and inherited from the father only
D. the result of a mutation in the child because neither parents has the disease
I would think it’s B. But of course, I don’t really know for sure.
I’m gonna say A I just finished a class on this with A+’s!
B. A recessive would have to be given by both parents, and neither parent would show the disease by themselves.
B. recessive and is carried by both parents. They may not have the disease BUT they are carriers of the gene. You need both parents to have the recessive gene and not show it for the gene to be recessive and be able to pass down to the child.
B.
Recessive means it’s there but not expressed in the phenotype unless two copies of the genes are present.
Like Cystic Fibrosis… the mother and father can both carry the genes but not have the disease because the gene is recessive. If, by chance, the child gets both the recessive copies, the chid will have CF.
B. is the correct answer.
recessive genes are not expressed in the genotype and
hence the phenotype.
But when 2 recessive genes are found, they are expressed
and the child gets the disease.
The last answer (D) is not correct as mutation happens in 1, or few cells not all his body cells.
C is not correct as it would have been expressed with his/her father.
If the disease is recessive, and both parents are heterozygous for the trait, they each could contribute the recessive allele, and the disease ould be seen in the child.
A spontaneous mutation is certainly possible, but not likely, and it would have to have taken place in the germ cells of one of the parents.
It is also possible that this could be a sex-linked condition passed to the child (assuming it’s a boy) by his mother (not his father). In sex-linked genetic problems, a woman can carry the allele for the trait on one X chromosome, and her other X chromosome will mask the expression of that gene. If she passes it to her son, however, his Y chromosome will not mask the expression of a gene on his X chromosome, so he will have the disease.
B!!! pick B!!
B – recessive genes require the pairing of both parents carrying the gene for the gene to surface in their offspring