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Recessive. Dominant alleles are expressed in both homozygous and heterozygous individuals (DD or Dd), but recessive alleles are only expressed in homozygous individuals (dd).

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Q: What is the type of allele that only effect the phenotype in the homozygous chromosome?
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Where are the effects o f a dominant allele seen?

it is present (shown) whenever it is present ( see Punnett Square) it will overthrow a recessive allele as long as it is there. it's effect is that you will get a certain trait for that allele. A Punnett Squar will help you the most.


What effect does natural selection have on the frequency of a recessive lethal allele?

Perhaps not much as the recessive allele is masked in heterozygous condition. Depends on penetration and expresivity of the lethal allele, but any homozygous expression is fatal, so one can expect negative frequency selection; the freqiency is kept low by selection.


What is dominant and recessive allele?

A dominant allele is an allele where its phenotype will always be represented when the allele for that gene is present. A recessive allele can be masked by a dominant allele when a dominant and recessive allele are present for the same gene. A recessive allele will only present itself when two recessive alleles for a trait are present.


What is the phenotype of a homozygous dominant person?

Homozygous dominant- means having dominant alleles at the same locus on a chromosome.More correctly, it's the same locus on two chromosomes (a homologous pair).


What could cause a mutant fly embryo to develop two tail ends but no head?

This is called bicoid mutant phenotype, and is caused by a maternal effect gene which is a gene that, when mutant in the mother, results in a mutant phenotype of the offspring regardless of the offspring's genotype.

Related questions

Two dominant alleles are expressed at the same time?

The alleles are not always both expressed.Take the simplest example, a case when there are only two alleles for a trait, R and r. When the organism is a heterozygote, meaning that it has both alleles with a genotype of Rr, only the phenotype carried by the dominant allele, the R, will be expressed. The dominant allele masks the phenotype of the recessive allele. A case in which only the dominant phenotype is expressed in a heterozygote is a case of complete dominance.*Cases where the dominant allele does not completely mask the recessive allele are cases of incomplete dominance and co-dominance.In incomplete dominance, the dominant allele has some effect on the recessive allele, but not a full effect. This results in a third phenotype in the population. Think red and white flowers leading to pink flowers.In co-dominance, the dominant allele has as much effect on the phenotype of the organism as the recessive allele. Think red and white flowers now leading to red and white streaked flowers.


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.


How does the homozygous gene affect horse color?

If a horse is homozygous dominant EE, he is black. Homozygous recessive ee, he is red. A black EE horse that is homozygous dominant for the Agouti gene (AA) will be a bay horse. If that same EE black were homozygous recessive for aa, then he would still appear all black. The Agouti gene does not effect a red ee horse's phenotype.


Where are the effects o f a dominant allele seen?

it is present (shown) whenever it is present ( see Punnett Square) it will overthrow a recessive allele as long as it is there. it's effect is that you will get a certain trait for that allele. A Punnett Squar will help you the most.


What effect does natural selection have on the frequency of a recessive lethal allele?

Perhaps not much as the recessive allele is masked in heterozygous condition. Depends on penetration and expresivity of the lethal allele, but any homozygous expression is fatal, so one can expect negative frequency selection; the freqiency is kept low by selection.


What is a phenotype-?

A phenotype is the physical trait or feature of an organism that is the effect of a particular genotype. Flower color of snapdragons is one example of a phenotype, and the color is determined by which alleles comprise the genotype. Plants that are homozygous for the flower color alleles are either white or red. Heterozygous snapdragons are pink.


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.


What is the difference between a genotype and a phenotype?

Phenotype, This is the "outward, physical manifestation" of the organism Genotype, This is the "internally coded, inheritable information"


What is a dominant allele what is a recessive allele?

An allele that hide the effect of other allele is called dominant.Allele that is masked is called recessive .


What is a heterozygous recessive?

Homogeneous recessive is two like genes that express a recessive trait.


How do dominant and recessive alleles affect an offsprings phenotype?

The traits inherited depends upon the alleles that have been passed on from the father and mother.The traits that are exhibited is called as the phenotype. Dominant allele needs only one copy to be expressed.For example in a pea plant "T" represents the tall dominant allele and "t" the short recessive allele .TT - when there are two dominant alleles the pea plant will express the tall trait. The pea plant is tall.Tt - when there is one dominant and one recessive allele the pea plant will still express the tall trait.In this case the dominant allele masks the recessive allele and the pea plant is still tall.tt - when there are two recessive alleles the pea plant will express the recessive trait and the pea plant is short.For a recessive trait to show up there should be a pair of recessive alleles.


What chromosome does Arthritis affect?

Arthritis does not effect a chromosome.