By "another pregnancy", I assume that the parents have had one child with cystic fibrosis. As cystic fibrosis is recessive and neither parent suffers from it, they must both be carriers. That means the chances of the next baby having CF is 25%, or a one in four chance. Assuming both parents have one CF and one non-CF gene, the combinations work out: non-CF x non-CF (normal) non-CF x CF (carrier) CF x non-CF (carrier) CF x CF (cystic fibrosis sufferer) Therefore their chances of having a: normal child = 25% child who is a CF carrier = 50% child who suffers from CF = 25%
Assuming that each parent is a carrier for cystic fibrosis (has the genotype Ff), the probability that their second child will develop cystic fibrosis is one fourth. The probability doesn't change with the number of children they have. For each pregnancy, the chance that the child will have cystic fibrosis (have the genotype ff) is exactly the same.
Let's call the gene "C." Capital C means no cystic fibrosis; lower c means cystic fibrosis, since it is a recessive gene. CC is a person who does not have cystic fibrosis and also is not a carrier. Cc indicated a carrier. cc shows a person with cystic fibrosis. In order for a child to have cystic fibrosis, its parents must be: 1. cc and cc (both have cystic fibrosis, so every child will as well.) 2. Cc and Cc (both carriers; 25% chance of having a child with cystic fibrosis) 3. Cc and cc (one parent is a carrier and one has cystic fibrosis; there is a 50% chance that the children will have cystic fibrosis.)
If both parents are carriers then the child has a 25% chance of having cystic fibrosis. If one parent has CF and the other the other was just a carrier then the child has a 50% chance of having CF. If one parent has CF and the other has two normal genes then there is no chance of the child having CF. If one parent is a carrier and the other has two normal genes then there is no chance of the child having CF. If both parents have CF then there is a 100% chance that the child will also have CF.
Zero. Cystic fibrosis is an autosomal recessive disease. This means that both parents must carry a mutated gene and have a 1 in 4 (25%) chance of having a child with CF.
Sure! When both parents are heterozygous carriers (Cc) for cystic fibrosis, the Punnett Square would result in a 25% chance of having a child with cystic fibrosis (cc), a 50% chance of having a child who is a carrier (Cc), and a 25% chance of having a child who is not a carrier and does not have the disease (CC).
To have cystic fibrosis both parents have to be a carrier. Each parent passes on one of their genes to their children; they each have one healthy and one cystic fibrosis gene. The child with cystic fibrosis receives a cystic fibrosis gene from each parent. The other child has at least one healthy gene if she does not have cystic fibrosis, though she could be a carrier. hope it would help
Cystic Fibrosis, is a recessive disease (meaning that both parents must be carriers of the cystic fibrosis gene, for the offspring to have a chance of being born with it). A child has a 25% chance (1/4) of being born with Cystic Fibrosis.
If both parents are just carriers of the gene that causes CF then there is a 75% chance that the child will not have CF. To break it down farther... 25% chance that they will have CF. 50% that they will be a carrier. 25% that they will have two normal genes.
If only one person is a carrier of cystic fibrosis than there is no chance of having a child with it. Both parents have to be carriers and even then there is only a 25% chance. If only one carries than there is a 50% chance that their children will carry but will not have cystic fibrosis.
No-False
For a baby to be born with Cystic Fibrosis, both parents must be carriers of the faulty CF gene. Where both parents carry the faulty gene, each child has a one in four chance of having CF, a two in four chance of being a carrier and a one in four chance of not having any CF genes.
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