homozygous recessive
testcross
If an individual is of the dominant phenotype, its genotype can be either AA or Aa (letter A picked for demonstration's sake). To do a good test cross, we have to be able to unambiguously tell which one of the genotypes the individual is. The best test cross would be conducted with a homozygous recessive (aa) individual. This way, if the cross generates 100% dominant phenotype, then the original individual was homozygous dominant. If the cross generates 50% dominant and 50% recessive phenotype, then the original individual was heterozygous.
To perform a testcross, you cross an individual with a dominant phenotype (but unknown genotype) with a homozygous recessive individual. By examining the offspring's phenotypes, you can determine the genotype of the unknown individual through the principles of Mendelian genetics. This allows you to determine if the individual is homozygous dominant or heterozygous for a specific trait.
A testcross is a genetic cross between an individual with a dominant phenotype but unknown genotype and a homozygous recessive individual. This cross is used to determine the genotype of the first individual by observing the phenotypic ratios of the offspring.
The AA genotype typically produces the phenotype associated with the dominant allele A. This means that the dominant trait will be expressed in the individual with this genotype.
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
Do a testcross with a homozygous recessive plant.
Do a testcross with a homozygous recessive plant.
The genotype AA represents a homozygous dominant genotype. The capital letter "A" represents the dominant allele, while the lowercase letter "a" would represent the recessive allele. If both dominant alleles are present in a genotype (homozygous dominant) then the phenotype is "A" phenotype. If one dominant allele and one recessive allele are present (heterozygous dominant) then the phenotype is "A". Finally, if both recessive alleles "a" are present (homozygous recessive) then the phenotype is "a". Therefore, the answer to your question is the genotype AA would result in an "A" phenotype because the genotype is homozygous dominant.
Homozygous dominant genotype (AA): The phenotype will show the dominant trait. Heterozygous genotype (Aa): The phenotype will also show the dominant trait due to the presence of at least one dominant allele. Homozygous recessive genotype (aa): The phenotype will exhibit the recessive trait.
Do a testcross with a homozygous recessive plant.
Do a testcross with a homozygous recessive plant.