The correct answer is aa only. The genotype aa would result in an individual with the recessive phenotype. aa is a homozygous genotype that…
Is genotype AA recessive?
Only individuals with an aa genotype will express a recessive trait; therefore, offspring must receive one recessive allele from each parent to exhibit a recessive trait. One example of a recessive inherited trait is a smooth chin, as opposed to a dominant cleft chin.
What is a recessive phenotype example?
Recessive phenotypes are basically versions of certain phenotypes that are masked . You can inherit the alleles for them, but they are not expressed unless you have only that allele. Some examples of this would be the diseases Sickle-cell anemia and Cystic Fibrosis.
What is an AA genotype?
The term “homozygous” is used to describe the pairs “AA” and “aa” because the alleles in the pair are the same, i.e. both dominant or both recessive. In contrast, the term “heterozygous” is used to describe the allelic pair, “Aa”.
Which blood type is recessive?
ABO Blood Type
The A and B genes are dominant and the O gene is recessive. For example, if an O gene is paired with an A gene, the blood type will be A.
Does genotype determine phenotype?
An organism’s phenotype is determined by its genotype, which is the set of genes the organism carries, as well as by environmental influences upon these genes.
What is a recessive phenotype?
Definition. A phenotype that requires two copies of the causal variant in an individual to occur.
How does genotype affect phenotype?
Genotype & Phenotype. Definitions: phenotype is the constellation of observable traits; genotype is the genetic endowment of the individual. Phenotype = genotype + development (in a given environment). … In a narrow “genetic” sense, the genotype defines the phenotype.
When the genotype consists of a dominant and a recessive allele?
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.
How do you determine a recessive phenotype?
The recessive phenotype is controlled by the homozygous aa genotype. Therefore, the frequency of the dominant phenotype equals the sum of the frequencies of AA and Aa, and the recessive phenotype is simply the frequency of aa.
What is not a phenotype?
The sum of an organism’s observable characteristics is their phenotype. A key difference between phenotype and genotype is that, whilst genotype is inherited from an organism’s parents, the phenotype is not. Whilst a phenotype is influenced the genotype, genotype does not equal phenotype.
What are examples of recessive genes?
Examples of Recessive Genes
Many traits are controlled by a single gene and are either dominant or recessive. Dimples, freckles, cleft chins, and a widow’s peak are all dominant traits, so not having these traits is recessive. A person will not have these traits if they have two recessive alleles.
What is the meaning of AA AS and SS genotype?
Blood genotype indicates of the type of protein (Haemoglobin) that is in the red blood cells. You could be Haemoglobin AA, AS, AC, SS or SC based on what is inherited from your parents. Individuals with blood genotype SC and SS are said to have sickle cell disease while AS is known as sickle cell trait.
Does negative sickling mean AA?
A sickle cell test looks only for the presence of hemoglobin S, which causes SCD. A negative test is normal. It means your hemoglobin is normal. A positive test result may mean you have sickle cell trait or SCD.
Can genotype AS and AA get married?
Compatible genotypes for marriage are:
That way you save your future children the worry about genotype compatibility. AA marries an AS. You’ll end up with kids with AA and AS which is good. But sometimes if you’re not lucky all the kids will be AS which limits their choice of partner.