What Is the Meaning of Law of Dominance?

Gregor Mendel was an Austrian priest and scientist who produced groundbreaking work in the theory of heredity. Although the importance of his research was not understood until after his death, Mendel’s law of dominance is the cornerstone of genetic comprehension.

History

• In the 1860s, Mendel studied pea plants to determine how genetic traits were passed from one generation to the other. At the time, scientists knew little of genetics and believed that the traits of parental entities blended together to produce offspring.

Significance

• Mendel noticed that when he mixed tall pea plants with short pea plants, all of the new pea plants were tall. Similarly, yellow-seeded pea plants crossed with green-seeded plants produced only yellow-seeded plants.

Effects

• The scientist concluded that, contrary to the opinion of the time, the crossing of tall and short parents would not produce offspring of average height, but rather, one of the two characteristics would dominate.

Law of Dominance

• Mendel’s law of dominance states that when an organism possesses two different genes as a trait, the gene that is expressed, overshadowing the other, is viewed as dominant, and the other recessive.

Considerations

• At the time, Mendel called these “factors,” as the word “gene” was not in usage or understood. Today, we use a capital “T” to describe the dominant, tall gene, and the lowercase “t” to express the short, recessive gene.