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How many copies of an allele need to be present for someone to have cystic fibrosis?
Wiki User
∙ 7y ago
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.
Wiki User
∙ 11y ago
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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 does it mean that CF is a recessive gene?
The phenotype associated with a recessive gene is only expressed when two copies of the gene are present. For example, if a person has both a recessive allele and a dominant allele for CF, the person does not have CF. The person only has CF if he/she has two copies of the recessive allele.
Is an allele that produces a trait in the heterozygous condition recessive?
No. A recessive allele will not be expressed phenotypically in the heterozygous state. A recessive allele can only be expressed phenotypically in the homozygous state.
What term describes an individual with two copies of the same allele?
The individual with two of the same allele is "homozygous" for a trait.
What is a recessive genes?
Recessive is a relative term used to describe the relationship to another allele termed the dominant allele. That traits of the recessive allele will only be shown if the person has two copies of the recessive allele. If a dominant allele is present, then the recessive trait will not be shown.
What is a trait that needs two factors in order to be expressed?
Actually, it is the recessive.................................................................UR WELCOME! :)
How is a recessive allele from a dominant allele?
its different because adominant allele is in charge
Describe the relationship between dominant and recessive trait forms?
The relationship between Dominant and recessive trait forms is simple a dominant trait is an allele that hides or masks another allele. While a recessive trait is the allele that is hidden or masked by another allele such as the dominant trait, the recessive trait is ONLY expressed when two copies of the recessive allele are present.
How many copies of the sickle cell allele do people with cycle cell disease inherit?
To display symptoms it requires 2 copies. Someone with one copy would only be a carrier and not display any symptoms.
A trait that requires two copies of an allele?
recessive
Why might certain traits skip a generation when breeding?
Traits are often dependent on certain alleles (variants for a single gene). The trait might express if two copies of the same allele A are present in the genome, or it might express only if some other variant allele B is not present. Due to the more or less random chromosomal crossover of genes involved in sexual reproduction, offspring might have two copies of A, one copy of A and one of B, or one of A and one of a third variant C. In each case, the dominance of the allele (whether it expresses if B or C are present), determines whether the trait is present in the offspring. Come the next generation, the reshuffling takes place again, with a new, mostly random outcome. So while allele A may be present in all three generations, the trait that depends on it does not have to be.
What the different between a dominant and recessive trait?
In simple Mendelian genetics, there may be several alleles (variations) for a given trait. since organisms generally have two pairs of chromosomes, they have two alleles. A dominant allele is one that when it is present, always shows itself. A recessive allele only shows when there are two copies of the recessive allele. For example, suppose brown hair is dominant and black hair is recessive. If there are any copies of the brown hair allele, the person's hair will be brown. A person's hair will be black only if they have two copies of the black hair allele. In reality, genetics is much more complicated than simply dominant and recessive as many genes may influence one trait.
