0
True False Cystic fibrosis is caused by a mutation that is the dominant allele of a gene?
Wiki User
∙ 12y ago
False.
Wiki User
∙ 12y ago
Add your answer:
Earn +20 pts
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 it true that a defective allele always recessive and a normal allele always dominant?
No. The gene that causes Huntington's is caused by an autosomal dominant mutation, and one form of inherited Parkinson's is also caused by an autosomal dominant mutation.
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 type of allele masks the expression of the recessive allele?
Two recessive alleles can not take over a dominant allele because there are only two alleles in a pair. This can only happen if there is a mutation because the dominant always takes over the recessive.
When on e allele of a gene masks the presence of the other allele what form is masked?
The recessive allele.
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 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).
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.
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.
What is an example of allele frequency?
The frequency for the mutant cystic fibrosis allele among Caucasians is 0.025, while the frequency of the normal allele is 0.975.
When C equals normal allele and c equals allele for cystic fibrosis Set up and complete a Punnett Square for cystic fibrosis for a couple that both have heterozygous for cystic fibrosis with no sympt?
M-> C c F C CC Cc c Cc cc phenotype- 3:1 genotype- 1:2:1
Do you need one or two parents to inherit cystic fibrosis?
you need two parents to get it but one parent to become a carrier. You need two parents with one of the alleles to inherit it but if you have one parent with the allele you might be a carrier. If you have two parents with the allele it does not mean that you will definitely have it. This is because the allele for cystic fibrosis is recessive.
Is it true that a defective allele always recessive and a normal allele always dominant?
No. The gene that causes Huntington's is caused by an autosomal dominant mutation, and one form of inherited Parkinson's is also caused by an autosomal dominant mutation.
