Mendelian Genetics - 1866 AD
“The breeding experiments of the monk Gregor Mendel in the mid‐1800s laid the groundwork for the science of genetics. He published only two papers in his lifetime and died unheralded in 1884. The significance of his paper published in 1866 on inheritance in peas (which he grew in the monastery garden) apparently went unnoticed for the next 34 years until three separate botanists, who also were theorizing about heredity in plants, independently cited the work in 1900. During the next 30 years, the universality of his findings was confirmed, and breeding programs for better livestock and crop plants—and the science of genetics—were well underway.
At the time of Mendel's work, scientists widely believed that offspring blended the characteristics of their parents, but Mendel's painstaking experimentation suggested this was not so.
Remember, no one had yet heard of genes, chromosomes, or meiosis, but Mendel concluded from his breeding experiments that particles or “factors” passed from the parents (rather than being homogeneously blended) to the offspring through the gametes and were directly responsible for the physical traits he saw first lost in the offspring's generation, then repeated in the next. Mendel even hypothesized that two factors, probably one from each parent, interacted to produce the results. His “factors” were, of course, the genes, which do, indeed, come in pairs or alleles for each trait.”
https://www.cliffsnotes.com/study-guides/biology/plant-biology/genetics/mendelian-genetics.
