Mendel’s primary observation was that traits like seed shape or flower color are governed by pairs of discrete units, which we now call genes. In his crosses, a plant with round seeds bred with a plant with wrinkled seeds did not produce semi-wrinkled seeds; it produced only round seeds. In the subsequent generation, the wrinkled trait reappeared in a predictable 3:1 ratio. This result suggested that some traits are dominant and others are recessive, but both are carried as distinct 'particles' rather than being diluted through mixing.

Mendel's experiments with pea plant hybridization replaced the prevailing "blending" model—which assumed offspring were a fluid average of parental traits—with a particulate theory of inheritance. By applying combinatorial mathematics to his findings, he identified that traits are governed by discrete factors that do not merge or dilute, even when they remain unexpressed in a specific generation. This observation that recessive traits can disappear and then reappear unchanged in a later generation proved that the underlying genetic information is digital and distinct rather than analog and fluid. It suggests that the complexity of life is built on a foundation of discrete, conserved units of information that remain stable across time.

Mendel also observed that different traits are inherited independently of one another. The inheritance of seed color did not influence the inheritance of seed shape. This 'Law of Independent Assortment' suggested that the biological organism is a mosaic of independent instructions. While later research found that some genes are linked on the same chromosome, Mendel’s work established the foundational logic of genetics as a combinatorial system. It raised the question of how many such instructions exist and where they are physically stored within the cell.