Short Answer

The law of dominance states that when two different forms of a gene are present together, only one form shows its effect. This form is called the dominant trait, while the other form remains hidden and is called the recessive trait.

This law was given by Gregor Mendel based on his experiments on pea plants. It helps explain why some traits appear in offspring even when only one parent carries that trait.

Detailed Explanation :

Law of Dominance

Meaning of the Law of Dominance

The law of dominance is one of the basic laws of inheritance given by Gregor Mendel. According to this law, when two different forms of a gene come together in an organism, only one form is expressed. This expressed form is known as the dominant trait, while the unexpressed form is known as the recessive trait.

This law explains why offspring often show only one of the parental traits, even though they inherit genes from both parents. The recessive trait does not disappear; it remains hidden and can appear in future generations.

Mendel’s Experiments Leading to the Law

Gregor Mendel discovered the law of dominance through his experiments on pea plants. He selected pure breeding plants with opposite traits, such as tall and short plants. When he crossed these plants, all offspring in the first generation were tall.

This result showed that the tall trait was dominant over the short trait. Even though the short trait was present in the genetic makeup, it did not appear in the first generation. This observation helped Mendel formulate the law of dominance.

Dominant and Recessive Traits

Dominant traits are those that express themselves even if only one parent passes the gene. Recessive traits appear only when both parents pass the same gene. In the presence of a dominant trait, the recessive trait remains hidden.

For example, if a plant receives one gene for tallness and one for shortness, it will be tall. The short trait is recessive and does not show its effect. This clear difference between dominant and recessive traits is explained by the law of dominance.

Expression of Traits in Generations

The law of dominance helps explain why some traits appear in one generation and disappear in another. In the first generation, the dominant trait appears. In the second generation, the recessive trait may reappear when two recessive genes come together.

This law also explains why some traits skip generations. Even when a recessive trait is not visible, it is still carried by the organism. Genetics helps identify these hidden traits.

Importance of the Law of Dominance

The law of dominance is important because it helps scientists understand inheritance patterns. It explains how traits are passed from parents to offspring and why some traits are more common.

In humans, this law helps explain inherited traits and some genetic disorders. For example, certain diseases are dominant, while others are recessive. Understanding this law helps in genetic counseling and medical diagnosis.

Law of Dominance in Plants and Animals

The law of dominance applies to many plants and animals. It is widely used in plant breeding to produce plants with desirable traits. Farmers use dominant traits to improve crop yield and quality.

In animals, breeders use this law to select animals with better traits such as strength or disease resistance. This shows the practical value of the law of dominance.

Limitations of the Law of Dominance

The law of dominance does not apply to all traits. Some traits show incomplete dominance or co-dominance, where both traits appear together. However, the law of dominance still remains a basic principle of inheritance.

Even with these limitations, the law of dominance provides a strong foundation for understanding more complex genetic patterns.

Role in the Study of Genetics

The law of dominance plays a key role in the study of genetics. It was one of the first laws to explain inheritance clearly. It helped scientists move forward in understanding genes and heredity.

Modern genetics builds on Mendel’s laws, including the law of dominance. This law remains important in biology education and research.

Conclusion

The law of dominance explains that when two different forms of a gene are present, only the dominant trait is expressed. The recessive trait remains hidden but is not lost. This law helps explain inheritance patterns, family resemblance, and genetic disorders. It is one of the most important contributions of Gregor Mendel to genetics.