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What is the probability of a child having cystic fibrosis if one of her parents was homozygous dominant and the other was a carrier for cystic fibrosis?
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.
Why does a person with Cystic Fibrosis have the genotype cc?
Cystic Fibrosis is inherited as a recessive trait. This means that both parents have to carry the allele for the defect. Both parents are Cc which means that 25% of their children will be CC (homozyous dominant and will not be able to pass the recessive allele in subsequent generations, 50% will be Cc(carriers) and 25% will be cc (homozygous reccessive and have Cystic Fibrosis).
What is cystic fibrosis gene disorder?
The genes on each chromosome control specific functions of the human body. The gene on chromosome 7 produces a protein called cystic fibrosis transmembrane regulator. Mutation in the DNA level of chromosome 7 leads to the absence of this protein which leads to cystic fibrosis. Cystic fibrosis is a recessive disease. It means that both copies of the gene must be defective. An affected person will have abnormal cystic fibrosis transmembrane regulator gene on each chromosome 7. Therefore both biological parents must have an abnormal gene. One abnormal copy is inherited from each parent. A person with one normal gene and one abnormal gene is called a cystic fibrosis carrier. Cystic fibrosis carriers do not show any symptoms but they may pass the abnormal gene to their children. Therefore the parents can be either cystic fibrosis carriers or affected themselves.
What is a punnett square for cystic fibrosis?
A Punnett square for cystic fibrosis would involve crossing two parents who are carriers of the recessive allele for the disease (denoted as "cf"). The square would show the probability of having a child with cystic fibrosis (25%), a carrier (50%), or unaffected by the disease (25%). Each parent would have a genotype of "Cf" (carrier) for the Punnett square.
Is it true that a defective allele always recessive and a normal allele always dominant?
No, a defective allele is not always recessive, and a normal allele is not always dominant. The relationship between alleles can be more complex and dependent on specific genetic mechanisms. Dominance and recessiveness are general terms used to describe the relationship between two alleles at a specific gene locus.
Is this true or false cystic fibrosis is caused by a mutation that is the dominant allele of a gene?
False. Cystic fibrosis is caused by a mutation in the CFTR gene, which is inherited in an autosomal recessive manner. This means that an individual must inherit two copies of the mutated gene (one from each parent) to develop the disease. If a person carries only one copy of the mutated gene, they are a carrier but do not exhibit symptoms of cystic fibrosis.
How do you deterime phenotypes?
phenotypes are decided by the alleles for that particular characteristic, by a dominant or two recessive alleles. For example, cystic fibrosis has a recessive allele so the phenotype of cystic fibrosis would only appear if there were two of the recessive allele, one from each parent, were present. A heterozygous carrier of the cystic fibrosis allele would show the phenotype of not having cystic fibrosis. So to determine the phenotype simply find out which allele is dominant and find what alleles each parent has the the probability of each phenotype can be calculated
Can you get Cystic fibrosis?
Cystic fibrosis is a genetic disease and can only be inherited through genes. It all depends on your parents alleles. Let's say that the allele for cystic fibrosis is c. If your Mum has the allele Cc it means she is hetrozygous. If you Dad has the same allele he is also hetrozygous. When they had children, the two small c's could come together to make a child with the alleles cc. (This means that the child has cystic fibrosis and has homozygous reccessive alleles.) When they had children their alleles could also come together to make CC (homozygous dominant- this means that person doesn't carry an allele for cystic firbrosis and will never get it. This means that if that person had children with another person who has the alleles CC, their child wouldn't get it), or it could make a child with Cc alleles. The child with Cc alleles wouldn't get cystic fibrosis because the allele big C (dominant allele) over powers the allele small c (reccessive- the cystic fibrosis allele). Although this person doesn't have cystic fibrosis their children might because they carry the allele for cystic fibrosis, which is c.
How many copies of an allele need to be present for someone to have cystic fibrosis?
Both cystic fibrosis and sickle cell anemia are single mutation diseases - one mutation in a single gene is enough to cause the disease. However, for cystic fibrosis both alleles of the gene must be mutated for the disease to develop. For sickle cell anemia, only one allele can carry the mutation and some signs of the disorder will be present. Having two alleles with the mutation causes much more significant disease.
What is the probability of a child having cystic fibrosis if one of her parents was homozygous dominant and the other was a carrier for cystic fibrosis?
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.
What is the genotype of woman with cystic fibrosis?
A woman with cystic fibrosis has a genotype that includes two copies of the mutated CFTR gene, which is located on chromosome 7. This means she is homozygous for the CFTR mutation, typically represented as "ff" where "f" indicates the presence of the cystic fibrosis allele. In cases where she has one normal CFTR allele and one mutated allele, she would be considered a carrier but would not exhibit symptoms of the disease. However, those with cystic fibrosis must have two copies of the mutated gene.
What must be true of a person with cystic fibrosis?
Both parents had at least one allele for cystic fibrosis.
Why does a person with Cystic Fibrosis have the genotype cc?
Cystic Fibrosis is inherited as a recessive trait. This means that both parents have to carry the allele for the defect. Both parents are Cc which means that 25% of their children will be CC (homozyous dominant and will not be able to pass the recessive allele in subsequent generations, 50% will be Cc(carriers) and 25% will be cc (homozygous reccessive and have Cystic Fibrosis).
Is cystic fibrosis complete dominance?
Cystic fibrosis (CF) is an autosomal recessive disorder, meaning that the disease manifests only when an individual has two copies of the mutated CFTR gene, one from each parent. In this case, the normal allele is dominant over the mutated allele, which means that carriers with one normal and one mutated allele do not exhibit symptoms of the disease. Therefore, cystic fibrosis is not an example of complete dominance, as the presence of one normal allele can mask the effects of the mutated allele.
Is cystic fibrosis controlled by a dominant allele or by a recessive allele?
It is controlled by a recessive allele. The gene encodes a chloride ion channel that is required to make sweat, mucus and a few other things. One copy of the gene is sufficient to prevent cystic fibrosis, and it is only when both copies are defective that the person would have the disease and show symptoms.
Why can Cystic fibrosis be inherited even if neither parent has the disease?
Cystic Fibrosis is an example of a disease inherited as an autosomal recessive genetic disorder. Both parents of a baby who has Cystic Fibrosis have one abnormal recessive gene and one normal dominant gene and are therefore, Cystic Fibrosis carriers. Carriers are said to be heterozygous because they contain one normal copy of the gene and one abnormal copy. A baby who inherits cystic fibrosis has inherited the abnormal gene from both parents and is therefore said to be homozygous recessive.
How can you get cystic fibrosis?
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.
