Gregor Mendel discovered the fundamental principles of genetic inheritance through his experiments with pea plants. His key discoveries include:

• Genes come in pairs and are inherited as distinct units, one from each parent. He deduced that each inherited trait is defined by a pair of genes (now called alleles), which segregate randomly during the formation of sex cells (gametes), so offspring inherit one allele from each parent. This is known as the Law of Segregation.
• Genes for different traits are inherited independently of one another, which is referred to as the Law of Independent Assortment.
• Some traits are dominant and will mask the expression of other traits that are recessive. An organism with alternate forms of a gene will express the dominant form. This is the Law of Dominance.

Mendel demonstrated these principles by breeding pea plants and observing how traits such as seed color, seed shape, flower color, and plant height were passed from one generation to the next. He showed that traits do not blend but are inherited as discrete units, with dominant traits masking recessive ones in the first generation but recessive traits reappearing in the second generation in predictable ratios

. His work laid the mathematical foundation of genetics long before the discovery of DNA and genes, and although it was not widely recognized until decades later, it became the cornerstone of modern genetics