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Why are recessive alleles not always expressed as the phenotype?
Wiki User
∙ 13y ago
recessive alleles get masked to show the difference
in a dominant gene and a recessive gene. the dominate
genes masks the recessive genes to show that the dominate
gene is more dominate or more likely to be the outcome than
the reccessive gene but the masked gene is not always recessive.
Wiki User
∙ 13y ago
Wiki User
∙ 12y agoRecessive Alleles are only expressed when there are two of them present. This is because when a recessive allele is present with a dominant allele it dominates over the recessive allele. Two different alleles cannot be expressed at one time.
Wiki User
∙ 14y agoThis is probably in ralation to the differences in regulatory regions (enhancer and promotore sequences) between dominance alleles and recessive alleles.
Wiki User
∙ 13y agobecause you cannot see them.
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In what alleles can be observed in the phenotype?
you mean phenotype, and its dominant alleles
Why phenotypes don't always express its entire genotype?
Phenotypes are the entirety of the observable traits. Genotypes are the instructions in the genetic code. Dominant alleles override the recessive alleles, making only the dominant alleles expressed.
What is recessive gene and dominant gene?
A dominant gene is always expressed if present, and the recessive gene is only expressed with the homozygous recessive genotype. For example, if the dominant gene is red (represented by the letter R) and the recessive gene is white (represented by the letter r), then a homozygous dominant organism's genotype will be RR, and its phenotype will be red. If the organism is homozygous recessive, then the genotype will be rr and the phenotype will be white. If the organism is heterozygous, then the genotype will be Rr, and the organism will be red.
What is the difference between dominant alleles and recessive alleles?
dominant-appears in first generation recessive-seems to dissapear
Another plant is said to be heterozygous for flower color what does this mean?
homozygous means that the alleles that make up the genotype are the same, for example homozygous dominant would have two dominant alleles (RR) or homozygous recessive would have two recessive alleles (rr). the alternative would be heterozygous, where the genotype contains both a dominant and a recessive allele (Rr). so a homozygous plant would either have two dominant alleles or two recessive alleles for the seed colour. Now the way to find out whether it is homozygous dominant or homozygous recessive is to do a cross with a homozygous recessive plant and look at the seed colour (the phenotype). if the the original genotype is homozygous dominant the offspring seed colour will show the dominant seed colour becasue it will be heterozygous. But if the original plant is homozygous recessive the offspring will show the recessive phenotype.
In what alleles can be observed in the phenotype?
you mean phenotype, and its dominant alleles
Why is it impossible for offspring to show the recessive trait if one parent is homoygous for the dominant trait?
Because the parent with the homozygous alleles for the dominant trait can only pass on that dominant allele to its offspring and the dominant allele, if present, is always expressed.
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.
What are alleles that have an effect on an organisms phenotype?
The presence of more than two alleles for a trait is known as probility. There might be one which is dormant and the others which are recessive.
What is recessive and dominant mean?
I am pretty sure the recessive and dominant alleles you are talking about are covered in Biology. Recessive alleles are basically alleles that are received from both parent's DNA that are carries, (dd). However, dominant alleles are (exactly what it says) always expressed. If there is one dominant allele and one recessive allele the dominant allele overpowers the recessive. (DD) and (Dd)overpowers (dd).
What gene is masked if it is paired with a dominant gene?
The different forms of a gene are called alleles. In Mendelian genetics, a gene has a dominant allele and a recessive allele. The dominant allele masks the recessive allele if present. So there are two possible dominant genotypes: homozygous dominant, in which both dominant alleles are present; and heterozygous, in which one allele is dominant and the other allele is recessive. The only way to express a recessive trait is to have the homozygous recessive genotype.
How are dominant and recessive genes related?
Dominate them. Recessive alleles do not show in your phenotype unless you have two of the same recessive allele. But if you inherit one dominant and one recessive, it is the dominant that always shows in your phenotype.
Why phenotypes don't always express its entire genotype?
Phenotypes are the entirety of the observable traits. Genotypes are the instructions in the genetic code. Dominant alleles override the recessive alleles, making only the dominant alleles expressed.
What is recessive gene and dominant gene?
A dominant gene is always expressed if present, and the recessive gene is only expressed with the homozygous recessive genotype. For example, if the dominant gene is red (represented by the letter R) and the recessive gene is white (represented by the letter r), then a homozygous dominant organism's genotype will be RR, and its phenotype will be red. If the organism is homozygous recessive, then the genotype will be rr and the phenotype will be white. If the organism is heterozygous, then the genotype will be Rr, and the organism will be red.
Organisms that are homozygous dominant and those that are for a trait controlled by simple dominance have the same phenotype?
Because the dominant gene always appears in the phenotype, whether or not it is "pure" (homozygous) or "mixed" (heterozygous). The recessive gene does what it says: it is recessive to the dominant gene. So, if it comes between the two, the dominant always appears. Of course, this only happens in your average Dominant-Recessive traits.
What is meaning of alleles?
An allele is the different forms of a gene. For example the gene for eye colour has the alleles; brown, blue, green etc. In every person there are two alleles for every gene but both alleles are not always the same. They can be dominant and recessive; dominant alleles are expressed no matter what other allele is present, recessive alleles require both alleles to be the recessive one to be expressed. E.g. say B is the allele for brown eyes and b is the allele for blue eyes. Brown is dominant therefore if someone had Bb or BB they'd have brown eyes and if they had bb their eyes would be blue.
According to the rule of dominance if two different alleles are present is the dominant allele expressed?
the dominant allele is expressed when two (assuming you mean dominant and recessive) alleles are present. however, if the alleles are codominant they are both expressed.
