both must be tt or both must be Tt
No. Parents with the dominant phenotype might be heterozygous in their genotype. This means they could carry both the dominant and recessive allele for a trait. So they could both pass the recessive allele to an offspring, who would then have the homozygous recessive genotype and recessive phenotype.
If both parents have the same phenotype, but the offspring did not share that phenotype, then it is likely that the parents have a dominant phenotype, but the offspring has a recessive phenotype, which means that the offpring's genotype would be homozygous recessive, and it's parents' genotypes would be heterozygous. For example, the parents may both have the genotype Bb, which gives them black fur. Approximately 25% of their offspring should have the genotype bb, which gives them the phenotype of white fur.
If both parents have the same phenotype, but the offspring did not share that phenotype, then it is likely that the parents have a dominant phenotype, but the offspring has a recessive phenotype, which means that the offpring's genotype would be homozygous recessive, and it's parents' genotypes would be heterozygous. For example, the parents may both have the genotype Bb, which gives them black fur. Approximately 25% of their offspring should have the genotype bb, which gives them the phenotype of white fur.
To produce a pea plant that only displays the recessive phenotype both of the parents must also have the recessive phenotype. In a four square, if one parent displays the recessive phenotype while the other has the dominant phenotype, one of every four offspring should theoretically receive the recessive phenotype as well, but if you want all offspring to be recessive, both parents must also be recessive. (tt)
If both parents have the same phenotype, but the offspring did not share that phenotype, then it is likely that the parents have a dominant phenotype, but the offspring has a recessive phenotype, which means that the offpring's genotype would be homozygous recessive, and it's parents' genotypes would be heterozygous. For example, the parents may both have the genotype Bb, which gives them black fur. Approximately 25% of their offspring should have the genotype bb, which gives them the phenotype of white fur.
Only a homozygous recessive individual will have the phenotype created by two recessive alleles.Since the term produce might indicate the production of offspring parents that can only produce offspring with a recessive phenotype must both have homozygous recessive genotypes.
Genotype: AA - The phenotype is homozygous dominant, exhibiting the dominant trait. Genotype: Aa - The phenotype is heterozygous, exhibiting the dominant trait. Genotype: aa - The phenotype is homozygous recessive, exhibiting the recessive trait.
It means that both parents have heterozygous genotype for a dominant trait, so they exhibit the dominant phenotype, but they each passed on the recessive allele to their daughter, so she has the homozygous recessive genotype, and therefore has the recessive phenotype, or trait. She could also have had a nondisjunction on one of the chromosomes inherited from her parents. She could have been adopted.
If 50% of the offspring show the dominant phenotype and 50% show the recessive phenotype, it is likely that one parent is heterozygous (Aa) for the trait and the other parent is homozygous recessive (aa). This would result in a 1:1 ratio of offspring showing each phenotype.
The homozygous recessive individual is used in a test cross to determine the genotype of an individual with a dominant phenotype but unknown genotype. When crossed with a homozygous recessive individual, if any offspring display the recessive trait, it indicates that the unknown individual is heterozygous for that trait.
The genotype ratio is 1:2:1 (1 homozygous dominant, 2 heterozygous, 1 homozygous recessive) and the phenotype ratio is 3:1 (3 individuals showing the dominant trait, 1 individual showing the recessive trait).
NO, because a dominant phenotype could either be homozygous or a heterozygous.so unless you are sure about the genotype of parents we can't determine it...but we can determine the genotype of a person showing reccessive phenotype, as a recessive trait always expresses itself in a homozygous condition..Read more: Is_it_possible_to_determine_the_genotype_of_a_person_showing_a_dominant_phenotype