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Why is it that a person with an allele for a particular trait may not have a phenotype that shows the trait?
Wiki User
∙ 9y ago
a dominant allele will express its trait , as well as be carried by the person. the word carrier is commonly used for a person who bears an allele which does not express itself(i.e. a recessive gene).
Wiki User
∙ 14y ago
Wiki User
∙ 9y agoBecause we usually have two alleles for a particular trait, and if they are different, sometimes one is dominant and one is recessive. Only the trait for the dominant allele will show in the phenotype.
Wiki User
∙ 14y agoThe dominant allele shows over the recessive allele. Therefore, if the person has the recessive allele, it will not show as it is overshadowed by thedominant allele.
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A single gene trait that has two alleles and that shows a simple dominant recessive pattern will result in?
A 3:1 phenotypic ratio (Mendelian inheritance).
How does a recessive trait show up as a visible trait?
Recessive alleles are only expressed in the phenotype if the organism is homozygous for the recessive allele (assuming diploidy). If the trait is sex-linked, then it will always show up in males if passed.
Why natural selection acts on the phenotype rather than genotype?
natural selection is a passive prosess . the mechanism of some individuals to be selected more than others is because they fit their environment more. and phenotype shows the fitness .
What happens when a dominant and recessive allele are both present?
The resulting offspring will have the dominant trait. It depends on if the dominant is hetero or homo...if it was homozygous then your offspring will have a hetozygous trait showing the dominant trait (to clear this up if you are confused lets say we are talking about brown eyes(BB-dominant) vs blue eyes(bb-recessive)--a homozygous would give you a brown eyed child with Bb and but if the person is heterozygous Bb and gets with a recessive you have a chance of getting Bb or bb giving you a possibility of a brown or blue eyed child)...wow i just made that way more confusing than it had to be
How does the range of phenotype differ between single-gene traits and polygenic traits?
Single gene traits are either one type or another,for example everyone is either (ABO System) group A,B AB or O with no intermediates - this shows discontinuous variation. In polgyenic traits, continuous variation is shown and there is a range with no discrete categories - height
What is an allele that always shows up in an organism's phenotype called - an allele that masks the other allele?
The dominant allele.
When one allele shows dominance over another allele?
When one allele shows dominance over another it is masking the expression of the other allele which is called "recessive".The word for this is complete dominance.
Why a person with an allele for a particular trait may not have a phenotype that shows the trait?
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What is an individual with genotype AAA described as?
An Aa genotype can result in the same phenotype as either an AA or AA genotype, if one of the alleles acts in a dominant fashion. If the A allele is dominant over the a allele, then the phenotype of a heterozygous (Aa) individual will be the same as the phenotype of a homozygous dominant (AA) individual.
Why a person with an allele for a particular trait may not have a phenotype that shows that trait?
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Does a dominant allele mask a ressessive allele?
In diploid organisms (those with two copies of each gene carried on separate chromosomes), one of the copies of a given gene may differ from the other copy of the same gene on the twin chromosome. In some cases one version of the gene (the dominant allele) has the effect of 'masking' the activity of the other (the recessive allele); that is, the presence of the dominant allele negates the effect of the recessive allele on the organism's phenotype. There are many mechanisms which can cause this phenomena, and it depends on the particular genes involved, but a simple model is one where the recessive allele is a biochemically inactive version of the dominant allele. In this case the dominant allele would mask the effect of the recessive allele by providing an active version of the gene. The dominant phenotype would be the one which shows the downstream effects of this activity, and the recessive phenotype one which shows the downstream effects of a lack of activity. The dominant allele is said to 'mask' the recessive allele because only one copy is required to result in an elimination of the recessive phenotype, whereas all copies of the gene must be the recessive allele to result in the recessive phenotype.
T is genetic trait for tallness and its allele t is recessive for tallness and their are four children with alleles TT tT Tt tt how many will be tall?
OK first, you don't say tT. The dominant allele is always put first. So this would actually be TT Tt Tt and tt. The only way a recessive trait will show is if the dominant trait isn't present. Therefore 3 will be tall and one will be short. BTW: TT isn't an example of an allele. It's actually the genotype. T is an example of an allele. Tallness is a genetic trait, but T is not. A genetic trait is simply a title that includes whatever phenotype may become apparent. A phenotype is the trait that shows up. If a person's genotype is TT or Tt, their phenotype will be tall. If a person's genotype is tt, then their phenotype will be short.
How do dominant and recessive alleles affect pheno type?
An allele can effect the phenotype of an organism by its dominance or recessiveness. If two dominant alleles are crossed the offsprings will carry the dominant trait of the alleles. If a dominant allele is crossed with recessive allele the phenotype of the offsprings will be of that of the dominant allele. And if two recessive alleles are crossed the phenotype of their offsprings will carry the reccesive trait.
Which is the dominant allele?
The dominant allele is the trait that shows up in the organism when the allele is present
What is a codominance?
Co-dominant allele is the one that shows dominance with another allele from a different loci. Basically its one of the following: 1) two different alleles at a locus are responsible for different phenotypes. 2) two alleles that affect the phenotype of the heterozygote. For instance ab blood groups
Using the terms dominant recessive explain the difference between genotype and phenotype?
No, I think you have your terms confused.The terms "dominant" and "recessive" are applied to alleles of a genotype. A genotype is an expression (using upper- and lower-case letters) that shows what alleles an organism has for a particular locus. The two alleles (in most cases) inherited (one from mother and one from father) can either be dominant or recessive. The recessive allele is not fully expressed in the presence of the dominant allele and is only expressed when there are two recessive alleles. The genotype could be called "recessive" I suppose if the genotype is homozygous recessive. But remember that two recessive alleles as a genotype is only one possibility - in which case you can't say the "genotype is recessive".The phenotype is dependent on the genotype. If present, the dominant alleles (in simple Mendelian genetics) will determine the phenotype - what the organism's trait or characteristic is. The phenotype will never be what is coded by the recessive allele unless the genotype is two recessive alleles.
What is a genotype with one dominant and one recessive gene?
The genotype of a person with one dominate allele for a gene and one recessive would be expressed as Aa or Yy. You can use any letter you would like except one will be shown as a capital (dominate) and one as a lower case (recessive). This combination is heterozygous for that trait.
