If the test cross results in any recessive offspring, then the parent organism is heterozygous for the allele in question. If the test cross results in only phenotypically dominant offspring, then the parent organism is homozygous dominant for the allele in question.
Can a dominant trait be heterozygous?
An organism with one dominant allele and one recessive allele is said to have a heterozygous genotype. In our example, this genotype is written Bb. Finally, the genotype of an organism with two recessive alleles is called homozygous recessive.
Are dominant traits homozygous?
A homozygous genotype is one in which both alleles are the same, and an organism with a homozygous genotype is said to be true-breeding or purebred. A homozygous dominant genotype is one in which both alleles are dominant.
Is AA homozygous dominant?
Homozygous means that both copies of a gene or locus match while heterozygous means that the copies do not match. Two dominant alleles (AA) or two recessive alleles (aa) are homozygous. One dominant allele and one recessive allele (Aa) is heterozygous.
What is the definition of homozygous dominant?
Homozygous means that the organism has two copies of the same allele for a gene. An organism can be homozygous dominant, if it carries two copies of the same dominant allele, or homozygous recessive, if it carries two copies of the same recessive allele. … Carriers are always heterozygous.
Is TT homozygous dominant?
When an organism has two of the same alleles for a specific gene, it is homozygous (homo means “same”) for that gene.
Genotype and Phenotype.
|Heterozygous||One dominant allele and one recessive allele||Tt|
|Homozygous dominant||Two dominant alleles||TT|
|Homozygous recessive||Two recessive alleles||tt|
Is it better to be homozygous or heterozygous?
So in the homozygous condition, a cell possesses either two same type dominant alleles (RR) or recessive alleles (rr). Whereas in the heterozygous condition the cell contains two non-identical alleles (Rr).
|When two identical alleles are present.||When two different alleles are present.|
What are the symptoms of heterozygous?
Signs and symptoms of heterozygous FH in adults include the following:
- Long-standing history of severe hypercholesterolemia dating back to childhood.
- If no previous acute coronary event, symptoms consistent with ischemic heart disease, especially in the presence of other cardiovascular risk factors (especially smoking)