Table of Contents
What is an example of a homozygous dominant genotype?
A homozygous dominant genotype is one in which both alleles are dominant. For example, in pea plants, height is governed by a single gene with two alleles, in which the tall allele (T) is dominant and the short allele (t) is recessive.
Is YY homozygous dominant?
YY is the homozygous dominant genotype (2 Y alleles). The phenotype of this genotype is yellow seed color. Yy is the heterozygous genotype (one dominant allele, one recessive allele).
What is a homozygous dominant 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. Heterozygous means that an organism has two different alleles of a gene. People with CF are homozygous recessive.
What are three examples of a homozygous dominant genotype?
A homozygous genotype can appear in various ways, such as:
- Eye color. The brown eye color allele is dominant over the blue eye allele.
- Freckles. Freckles are tiny brown spots on the skin.
- Hair color. Red hair is a recessive trait.
How can you tell if someone is heterozygous or homozygous for a dominant trait?
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.
Is AA homozygous dominant?
A homozygous dominant (AA) individual has a normal phenotype and no risk of abnormal offspring. A homozygous recessive individual has an abnormal phenotype and is guaranteed to pass the abnormal gene onto offspring.
Is AaBb homozygous dominant?
Both parents are heterozygous and so they have the genotype of AaBb. Since they both have dominant genes, they will have phenotypes consisting of the dominant traits. As we have said previously, we are only considering pairs of alleles that are not linked to one another, and are inherited independently.
Is FF homozygous or heterozygous?
Mendelian Genetics
| Genotype | Phenotype | |
|---|---|---|
| F F | Homozygous dominant | No cystic fibrosis (Normal) |
| F f | Heterozygous | Carrier (has no symptoms but carries the recessive allele) |
| f f | Homozygous recessive | Cystic fibrosis (has symptoms) |
What is the percentage of a homozygous dominant offspring?
| PARENT GENOTYPES | OFFSPRING PHENOTYPES |
|---|---|
| pure (homozygous) dominant x anything | 100% of offspring with dominant trait |
| hybrid x homozygous recessive | 50% dominant trait, 50% recessive trait |
| hybrid x hybrid | 75% with dominant trait & 25% with recessive trait |
| homozygous recessive x homozygous recessive | 100% recessive trait |
Are humans homozygous or heterozygous?
Homozygous and Heterozygous Since humans possess two copies of each chromosome, they also have two copies of each gene and locus on those chromosomes. If the alleles are different, the person is heterozygous for that trait.
Are humans homozygous?
Sex-determination in humans is dependent on the sex chromosomes. Males are said to be “hemizygous” for any X-chromosome genes, meaning that there are only half (“hemi”) as many alleles as normally present for a diploid individual.