Is BB dominant or recessive?
An organism with two dominant alleles for a trait is said to have a homozygous dominant genotype. Using the eye color example, this genotype is written BB. 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.
What is the letter of the dominant allele?
A dominant allele is denoted by a capital letter (A versus a). Since each parent provides one allele, the possible combinations are: AA, Aa, and aa. Offspring whose genotype is either AA or Aa will have the dominant trait expressed phenotypically, while aa individuals express the recessive trait.
What is BB and BB?
So for eye color, brown is B and blue is b. As I said above, people have two versions of each gene so you can be BB, Bb, or bb–BB and Bb have brown eyes, bb, blue eyes. … As you can probably guess, if the blue version of the eye color gene made a pigment, then you’d get some mix of brown and blue.
What are recessive genes?
A recessive gene is a gene that can be masked by a dominant gene. In order to have a trait that is expressed by a recessive gene, such as blue eyes, you must get the gene for blue eyes from both of your parents. You might remember the word recessive from biology, where it most often appears.
Is O 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.
Why is O blood type recessive?
The gene for type O is ‘recessive’, because if you have one gene for O and one for A, then you still end up with A antigens on your cell membranes, and the same goes for O and B. In order to be group O, you need both parent cells to be O.
What is heterozygous recessive?
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.
Why is the R allele recessive to both B and W?
the R allele is recessive to both B and W because the B and W alleles both block the expression of the R allele, so the melanocyte’s membrane contains no R versions of MC1R. Allele S is derived from B. Like B, allele S contains a mutation that would cause MC1R to be stuck on.