A homozygous recessive allele combination contains two recessive alleles and expresses the recessive phenotype. For example, the gene for seed shape in pea plants exists in two forms, one form (or allele) for round seed shape (R) and the other for wrinkled seed shape (r).
What is an example of homozygous recessive?
Finally, the genotype of an organism with two recessive alleles is called homozygous recessive. In the eye color example, this genotype is written bb. Of these three genotypes, only bb, the homozygous recessive genotype, will produce a phenotype of blue eyes.
What is an example of homozygous gene?
You can have brown eyes whether you’re homozygous (two alleles for brown eyes) or heterozygous (one for brown and one for blue). This is unlike the allele for blue eyes, which is recessive. You need two identical blue eye alleles in order to have blue eyes.
What is an example of a recessive gene?
Examples of Recessive Traits
For example, having a straight hairline is recessive, while having a widow’s peak (a V-shaped hairline near the forehead) is dominant. Cleft chin, dimples, and freckles are similar examples; individuals with recessive alleles for a cleft chin, dimples, or freckles do not have these traits.
What does homozygous recessive gene mean?
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.
Is AA homozygous recessive?
Two dominant alleles (AA) or two recessive alleles (aa) are homozygous. One dominant allele and one recessive allele (Aa) is heterozygous.
Is RR homozygous recessive?
A homozygous plant contains either of the following alleles for seed shape: (RR) or (rr). The (RR) genotype is homozygous dominant and the (rr) genotype is homozygous recessive for seed shape.
What is a recessive allele?
Recessive refers to a type of allele which will not be manifested in an individual unless both of the individual’s copies of that gene have that particular genotype.
Is JJ dominant or recessive?
Another gentleman does not possess this gene – instead, he has the recessive jj gene which means his joints bend normally. A boy is born with an extra finger on each hand due to the dominant gene EE, while another newborn with the recessive homozygous ee gene has the normal number of fingers on her hands.
What do you mean by recessive trait?
A recessive trait is the weak, unexpressed trait of a dichotomous pair of alleles (dominant-recessive) that has no effect in the phenotype of heterozygous individuals.
What are homozygous and heterozygous alleles?
Homozygous: You inherit the same version of the gene from each parent, so you have two matching genes. Heterozygous: You inherit a different version of a gene from each parent.
Is red hair a recessive gene?
The gene for red hair is recessive, so a person needs two copies of that gene for it to show up or be expressed. That means even if both parents carry the gene, just one in four of their children are likely to turn out to be a redhead.
Is blonde hair recessive?
The blond allele is recessive, and gets covered up. You can think of recessive alleles as t-shirts, and dominant ones as jackets. … Since you have two copies of each gene, that means the only way to have a recessive feature like blond hair is for both of them to be the recessive allele.
What is heterozygous example?
If the two versions are different, you have a heterozygous genotype for that gene. For example, being heterozygous for hair color could mean you have one allele for red hair and one allele for brown hair. The relationship between the two alleles affects which traits are expressed.
What is an example of homozygous dominant?
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.