Gregor Mendel (1823-1884)
A simple son of farmers, Gregor Mendel became a monk to pursue his studies. It was this man that first discovered hereditary and studied genetics before anyone else had.
During his time, genetics was an unknown science. Mendel's studies were unknown of. However, today no one questions this theory and it is taken as a known fact. Much of our knowledge of hereditary its genetics is owed to this man.
Gregor Mendel experiments with "cross-breeding" pea plants helped explain how traits were inherited in his work "Experiments With Plant Hybrids" he explained his theories. This book became one of the greatest books of science ever.
Mendel also discovered that traits were inherited in a ratio form and he came up with the idea of dominance and segregation of genes. He worked his theory for many years and finally founded some basic laws of genetics.
Gregor Mendel's works became a basis for more modern genetics and it has advanced far from then. Today, genetics is becoming the most prominent form of science.