Example of Incomplete Dominance

Austrian monk Gregor Johan Mendel uncovered important insights concerning heredity. Mendel was the first to foresee the features handed down from parents to children.

He is referred to as "The Father of Genetics" since he uncovered the fundamentals of the field. Mendel experimented with garden pea hybrids between 1856 and 1863. (Pisum sativum). He decided on a few distinctive qualities of the peas throughout that time.  

Mendel's Law of Inheritance

Mendel's inheritance laws describe how traits are passed down from parents to offspring. These laws were discovered by Gregor Mendel, an Austrian monk, and botanist, in the mid-19th century. Mendel's experiments involved breeding pea plants and carefully tracking the inheritance of specific traits over multiple generations.  

• The Law of Segregation states that when gametes develop, alleles segregate, and each gamete bears a single copy of each gene.  
• The rule of independently varying: Alleles for one gene segregate independently of alleles for other genes.  
• The Law of Dominance states that an organism with two possible gene variants will express the dominant form.  

Mendel's laws provide the foundation for our understanding of genetics and heredity. They help explain why offspring inherit specific traits from their parents and how new variations of characteristics arise over time through genetic mutations and recombination.  

Incomplete Dominance  

When an organism's phenotype reflects a mixing of both alleles, this phenomenon is known as incomplete dominance. It occurs when a dominant allele or gene form does not entirely conceal or disguise the effects of a recessive allele.

Snapdragon is a prime example of imperfect dominance (Antirrhinum majus). Pink flowers result from a cross between a homozygous parent with white flowers and a homozygous parent with red blooms.  

Examples:   

Wavy hair is an example of incomplete dominance in humans. The two alleles for curly or straight hair are present. If a person has homozygosity for both alleles, their hair will be straight or curly. However, suppose a person inherits one gene for curly hair and one allele for straight hair.

In that case, they will have wavy hair if heterozygous for hair texture because the two alleles interact to produce a distinct phenotype, indicative of incomplete dominance.  

Co-Dominance  

Co-dominance is an inheritance pattern where both alleles (versions of a gene) in a heterozygous individual (an individual with two different alleles for a particular gene) are expressed equally in the phenotype. In other words, neither allele is dominant nor recessive, and both contribute to the individual's physical appearance.  

Co-dominance differs from incomplete dominance, where the heterozygous phenotype is a blend of the two alleles, such as in the case of pink flowers resulting from the combination of red and white flower alleles.  

Examples:  

In humans, the ABO blood group system is controlled by three alleles: A, B, and O. Alleles A and B are co-dominant, meaning that if an individual inherits one A allele and one B allele, they will express both A and B antigens on their red blood cells, resulting in AB blood type.  

Another example of co-dominance can be seen in the case of roan cattle, which have a coat color that is a mixture of red and white hairs. This is because the alleles for red and white coats are both co-dominant, resulting in a blended appearance.