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Mendel conducted breeding experiments with pea plants (Pisum sativum) to study the inheritance of traits. He focused on seven characteristics such as seed color, seed shape, flower color, and growth habit. Mendel crossed pure-bred plants with contrasting characteristics and observed their offspring (the F1 generation). Then, he allowed the F1 generation to self-fertilize and studied the F2 generation.

From his pea plant experiments, Mendel formulated three laws of inheritance: 1. Law of Dominance: In a cross between two homozygous plants (AA x aa) with contrasting traits, the dominant trait will be expressed in the F1 generation, while the recessive trait seems to disappear. 2. Law of Segregation: When the F1 generation undergoes self-fertilization, the traits separate in the F2 generation, and the recessive trait reappears in a consistent ratio (3 dominant : 1 recessive). 3. Law of Independent Assortment: The inheritance of one trait is independent of the inheritance of another trait. Trait combinations result from the random assortment of the unit factors that control them.

Mendel's work was initially overlooked but was rediscovered in 1900 by three scientists – de Vries, Correns, and Tschermak. This led to a greater understanding of chromosomes, leading to the chromosome theory of inheritance. Genes were later identified as the fundamental units of heredity residing on chromosomes, responsible for transmitting traits from parent to offspring.

Mendel's laws still form the basis of our understanding of genetics. They provided the groundwork for the central concepts of gene interaction, dominance, and inheritance patterns. His laws were crucial in helping scientists develop the field of molecular genetics, which studies the structure and function of genes at a molecular level. Mendel's laws are still applicable to a wide range of organisms, including humans, and help us understand how traits are inherited, how populations evolve, and predispositions to genetic diseases. Today, our knowledge of genetics has expanded tremendously, including genetic engineering, gene therapy, and genome editing. In conclusion, Mendel's work on the transmission of traits is the foundation of our understanding of genetics today. His laws of inheritance have guided the development of numerous advancements in the field of genetics, allowing scientists to understand the molecular mechanisms underlying inherited traits and develop strategies to address various genetic diseases and disorders.