Help With Cystic Fibrosis? Grade 10 Science..// Genetics?
Thursday, December 16th, 2010 at
5:37 pm
A question from ken l: Help with Cystic Fibrosis? grade 10 science..// genetics?
I would like to know the risk of having a child who has the disese or is a carrier when
1) both parents are carriers of the gene for the disease
2) one parent is a carrier
3) one parent has the disease ( and can have children), and the other is a carrier
Most comprehensive answer:
Answer by Gibb
Do a punnett square dude…
Whether you agree or disagree, why not leave your own thoughts below.
Tagged with: cystic • fibrosis • GENETICS • grade • help • Science
Filed under: Cystic Fibrosis
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If both parents are carriers of the gene for the disease, then there is quite a high chance of the offspring inheriting cystic fibrosis. Just use a punnett square, since this is an autosomal recessive disorder, the homozygous recessive genotype can only inherit the disorder:
C c
C CC Cc
c Cc cc so there is a 25% chance the offspring will inherit the disorder (cc)
2) When one parent is a carrier and one is normal, the genotypes are: Cc and CC
C c
C CC Cc
C CC Cc Since dominant alleles mask recessive ones, there is a 0% chance the offspring will inherit the disorder
3)
You know that the genotypes are cc and Cc, now try out your own punnett square this time!
I hope I helped
1) There is a 1 in 4 chance of the child having the disorder, and a 1 in 2 chance of the child being a carrier.
2) there is a 1 in 4 chance of the child being a carrier.
3) there is a 3 in 4 chance of the child having the disease, the child will be a carrier if the do not get the disease.
To show your working, draw 2 people, and each person has 2 genes to pass on, Make CF genes red and healthy genes white, each parent passed on one gene, so you can make all different variables.