Ironically, another important discovery that probably would have changed Darwin's views (and maybe have saved him some embarrassment from endorsing pangenesis) appeared shortly after Darwin had published The Origin of Species.
Gregor Mendel, a monk-turned-scientist, was born in the present day Czech Republic to a farming family (DNA Watson). He excelled as a child in the local school of his village, but his later endeavors as an adult flailed; he failed his teaching exam twice and had a nervous breakdown trying to become a parish priest (DNA Watson). At the request of his father superior, Abbot Napp, Mendel tried his hand at some scientific experiments involving heredity. Using an ingenious design, Mendel crossbred two strains of the plant (one with green peas, the other with yellow peas) and noted the ratios of the resulting progeny (Monk and Two Peas, notes 407). His results led him to realize that specific factors (what we now call genes) are passed from parent to offspring in pairs, one "factor" from each parent (DNA Watson). From his ratios and observations Mendel also deduced that certain factors were dominant over others, or stated another way, certain factors receded to other, more dominant factors (Monk and Two Peas, Notes 407). Despite the impressive discoveries of Mendel, his work would go ignored by the scientific community for another 35 years (DNA Watson). Around the time of Mendel's death in 1884, improving optics of microscopes led to the discovery of the minute cellular architecture, later termed the "chromosome" (DNA Watson). It wasn't until 1902 that the chromosome and Gregor Mendel met up.
Walter Sutton, a medical student at Columbia University, recognized the similarities between the chromosomes and Mendel's research, more specifically, his "certain factors" (DNA Watson). Sutton saw that chromosomes were doubled-up, just like Mendel's paired factors, but he also identified a type of cell in which they were not paired (DNA Watson).