Any cross of parents for a single trait where the dominant allele completely masks any expression of the recessive allele as follows:
Parents are both heterozygous for the trait. For example Aa X Aa produces 75% of offspring with the dominant phenotype and 25% with the recessive phenotype.
One parent is heterozygous for the trait and the other parent is homozygous recessive. For example: Aa X aa produces 50% offspring with the dominant phenotype and 50% offspring with the recessive phenotype.
If the trait is co-dominant/non-dominant a heterozygote would have the median characteristic and a homozygote could be either of two phenotypes. If T is tall and t is short the Tt offspring would be
medium in this example. The way to produce offspring with only two phenotypes would be to cross a heterozygous parent with a homozygous parent. For Example:
Tt X tt cross would produce 50% tt (short) offspring and 50% Tt (medium) offspring. A TT X Tt cross would produce 50% TT (tall) offspring and 50% Tt (medium) offspring.
single-gene and polygenic
Species A will have fewer phenotypes. (apex)
two
punnet square
Parental Phenotypes are when the offspring of two parents look like one of the two parents. for example, if a green wrinkled pea is crossed with a heterozygous yellow round pea the offspring are 1/4 yellow round, 1/4 green wrinkled, 1/4 yellow wrinkled, and 1/4 green round. the yellow round and green wrinkled look like the parents so they have parental phenotypes, whereas the yellow wrinkled and the green round have combinations of the parental phenotypes thus they have recombinant phenotypes.
You can see the phenotype. A good way to remember is that a photograph is what you see. The genotype is the graphic representation of the trait.
Two
Aa AA aa If A dominant, two phenotypes.
Many possible genotypes, producing ,any possible phenotypes.
I think you have the question backwards, "Why isn't it possible to have more phenotypes than genotypes?" There are always more or an equal number of genotypes relative to phenotypes. The phenotype for a simple dominant/recessive interaction (for example) T for tall and t for short where TT is tall, Tt is tall and tt is short has three genotypes and two phenotypes. If T and t are co-dominant then TT would be tall, Tt would be intermediate and tt would be short. (Three phenotypes and three genotypes.)
Many possible genotypes, producing ,any possible phenotypes.
yes
Possible genotypes would be AA and Aa. Phenotypes cannot be determined here because they are the physical, observable results of a genotype.
dkOD
Highly reduced, or, nonexistent.
Alleles
The possible genotypes and phenotypes of the offspring can be determined using a Punnett square, a grid that shows the possible combinations of alleles that can result at fertilisation. The Punnett square below shows the expected genotypes of the offspring of parent pea plants that both have the genotype Rr.
Eight.