An allele is a small piece of DNA responsible for some characteristic that plugs into a gene locus (or position) along a chromosome. Suppose the particular gene locus is responsible for flower colour in some plant. There may be alleles that plug in amongst the plant population for red or yellow flowers. Since chromosomes are paired, several combinations are possible. Both alleles may be red so the flower will be red and similarly for yellow. If there is a red allele and a yellow allele you may either get orange flowers but if one allele is dominant over the other the flower colour will be either red or yellow depending on which allele is dominant. If the red allele is dominant over the yellow there will be more red flowers. If it was only as simple as this three quarters of the flowers would be red and onequarter would be yellow. For two possible alleles with red dominant over yellow, there are four combinations:- R R Red flowers
R Y Red flowers
Y R Red flowers
Y Y Yellow flowers
The allele for the sickle cell trait is codominant with the normal allele. This means that in individuals with both alleles present, both traits are expressed.
Dominant markers show only the dominant allele and mask the recessive allele, while codominant markers show both alleles separately. With dominant markers, heterozygotes can't be distinguished from homozygous dominant individuals, while with codominant markers, heterozygotes display a distinct phenotype from homozygous individuals. Dominant markers are easier to interpret but may not provide as much information as codominant markers.
In a situation where both a dominant and recessive allele are present in a gene pair, the dominant allele will be expressed phenotypically. The presence of a dominant allele overrides the expression of the recessive allele.
When two alleles are codominant, that means that they are expressed simultaneously in different parts. For example, if a red and white flower were crossed, and the resulting flower had some red petals and some white petals that would be codominance. Another example is when animals have stripes and spots. Not to be confused in incomplete dominance, which is when two alleles are expressed simultaneously in the same part of the organism (in the flower example all the petals would be pink).
Blood types is a good example of codominance. There are three alleles for blood type, that can be represented as IA, IB, and i. IA and IB are both dominant to i, but when an individual inherits one of each the former two alleles (IAIB), he or she will have type AB blood. Instead of one allele being straightforwardly dominant to another, or the resulting phenotype being a halfway stage between the two alleles, the phenotype has aspects directly resulting from each allele.
codominant
codominant
The allele for the sickle cell trait is codominant with the normal allele. This means that in individuals with both alleles present, both traits are expressed.
Dominant markers show only the dominant allele and mask the recessive allele, while codominant markers show both alleles separately. With dominant markers, heterozygotes can't be distinguished from homozygous dominant individuals, while with codominant markers, heterozygotes display a distinct phenotype from homozygous individuals. Dominant markers are easier to interpret but may not provide as much information as codominant markers.
This would depend on whether the allele for dimples is dominant or recessive. If the allele for dimples is dominant and the no dimples allele is recessive then the phenotype of the individual would be dimpled. If the allele for no dimples is dominant and the allele for no dimples is recessive then the dimples will not be expressed. If these alleles are codominant then the dimples will be expressed but not as much as in an individual who has both alleles for dimples.
This would depend on whether the allele for dimples is dominant or recessive. If the allele for dimples is dominant and the no dimples allele is recessive then the phenotype of the individual would be dimpled. If the allele for no dimples is dominant and the allele for no dimples is recessive then the dimples will not be expressed. If these alleles are codominant then the dimples will be expressed but not as much as in an individual who has both alleles for dimples.
In a situation where both a dominant and recessive allele are present in a gene pair, the dominant allele will be expressed phenotypically. The presence of a dominant allele overrides the expression of the recessive allele.
This would depend on whether the allele for dimples is dominant or recessive. If the allele for dimples is dominant and the no dimples allele is recessive then the phenotype of the individual would be dimpled. If the allele for no dimples is dominant and the allele for no dimples is recessive then the dimples will not be expressed. If these alleles are codominant then the dimples will be expressed but not as much as in an individual who has both alleles for dimples.
Codominance is what it is called. That is when neither allele is completely dominant over the other.
Each person has two alleles of one particular gene, which controls one particular characteristic, such as a person's blood group. An allele may be either dominant, recessive, or codominant. A dominant allele would dominate the other allele in the chromosomes, meaning only the dominant allele would contribute to an organism's characteristics. An example of this is the A blood group, which is dominant to the O allele. However, if an individual has both A and B alleles, A and B are codominant, as they both exhibit effects on an organism's characteristics (the blood group). This results in an AB blood group - a combination of the effects of two genes!
When two alleles are codominant, that means that they are expressed simultaneously in different parts. For example, if a red and white flower were crossed, and the resulting flower had some red petals and some white petals that would be codominance. Another example is when animals have stripes and spots. Not to be confused in incomplete dominance, which is when two alleles are expressed simultaneously in the same part of the organism (in the flower example all the petals would be pink).
Blood types is a good example of codominance. There are three alleles for blood type, that can be represented as IA, IB, and i. IA and IB are both dominant to i, but when an individual inherits one of each the former two alleles (IAIB), he or she will have type AB blood. Instead of one allele being straightforwardly dominant to another, or the resulting phenotype being a halfway stage between the two alleles, the phenotype has aspects directly resulting from each allele.