In the mid-1800s, Gregor Mendel conducted a series of meticulous experiments that contradicted the prevailing theory of blended inheritance. He bred pea plants that varied in appearance and recorded the appearances of plants in each succeeding generation. He observed that different forms of each trait, which we now call alleles, segregated into gametes. This is the principle of segregation. He also observed that some alleles coded for a dominant trait, and these dominant traits were observed even in the presence of the allele coding for a recessive trait. This is the principle of dominance. Although meiosis had not yet been discovered, Mendel predicted it conceptually, by observing that multiple traits from each parent sorted independently into offspring, creating new combinations of traits that did not exist in either parent. This is the principle of independent assortment.