Скачать или смотреть Co dominance and Incomplete dominance

Co-dominance and incomplete dominance are two patterns of inheritance that describe how alleles (different versions of a gene) interact and influence the phenotype (observable traits) of an organism.

Co-dominance:
Co-dominance occurs when two different alleles for a particular gene are both fully expressed in the heterozygous individual, meaning that neither allele is dominant or recessive over the other. As a result, both alleles are visibly expressed in the phenotype, often leading to a mixed or blended phenotype.

A classic example of co-dominance is the blood type system in humans, specifically the ABO blood group. In this system, there are three alleles for a single gene: IA (codes for antigen A), IB (codes for antigen B), and i (codes for no antigen, or O). When an individual inherits an IA allele from one parent and an IB allele from the other, their blood type will be AB, and both A and B antigens will be expressed on the surface of their red blood cells.

Incomplete Dominance:
Incomplete dominance occurs when neither of the two alleles is completely dominant over the other, resulting in an intermediate phenotype in heterozygous individuals. In this case, the alleles blend or mix together to create a phenotype that is different from either homozygous state.

An example of incomplete dominance is seen in the flower color of snapdragons. There are two alleles for this trait: RR (red flowers) and rr (white flowers). Incomplete dominance occurs when an Rr heterozygous individual has pink flowers because the red and white alleles combine to produce a mixture of red and white pigments, resulting in a pink phenotype


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