The phenotype is the physical manifestation of an organism’s allellic combination (genotype). For the pea plants, if the red allele is dominant and the white allele is recessive, only two phenotypes are possible. … Often, organisms will carry a dominant and a recessive allele of a gene.
Are alleles or phenotypes dominant?
Alleles contribute to the organism’s phenotype, which is the outward appearance of the organism. Some alleles are dominant or recessive. When an organism is heterozygous at a specific locus and carries one dominant and one recessive allele, the organism will express the dominant phenotype.
What are the 3 types of genotypes?
There are three types of genotypes: homozygous dominant, homozygous recessive, and hetrozygous.
How many different phenotypes are possible?
Even though only four different phenotypes are possible from this cross, nine different genotypes are possible, as shown in Figure 13.
Is homozygous dominant?
An organism with two dominant alleles for a trait is said to have a homozygous dominant genotype. Using the eye color example, this genotype is written BB. An organism with one dominant allele and one recessive allele is said to have a heterozygous genotype.
Which best defines a dominant trait?
Dominant: A genetic trait is considered dominant if it is expressed in a person who has only one copy of that gene. (In genetic terms, a dominant trait is one that is phenotypically expressed in heterozygotes).
How do you determine dominant phenotype?
Use the Hardy-Weinberg equilibrium.
- Alleles: p+q=1.
- p=frequency of the dominant allele. …
- p2=frequency of homozygous dominant genotype. …
- In your scenario, the dominant phenotype has a frequency of 0.19 .
- This is misleading, since both the p2 and 2pq terms represent the dominant phenotype. …
- If q2=0.81 , we can determine q .