On February 8, 1865, in the Czech Republic, a significant breakthrough in biology occurred when Augustinian friar Gregor Mendel presented his pioneering experiments with pea plants, laying the foundation for the field of modern genetics. Over eight years, Mendel cultivated and crossbred more than 28,000 pea plants (Pisum sativum) in the garden of the Monastery of St. Thomas in Brno. His meticulous observations revealed that heredity is transmitted in discrete units, challenging the prevailing views of the time.
Despite facing skepticism from his peers, including ridicule from his bishop, Mendel remained committed to his research. In a letter from 1859, his abbot Cyril Napp expressed concern over the legitimacy of studying pea plants, suggesting that Mendel focus on more esteemed subjects. Nevertheless, Mendel’s determination to uncover the principles of inheritance propelled his groundbreaking work forward.
Mendel chose to study pea plants for several reasons. They reproduce quickly and exhibit clear traits, such as flower color and seed shape. He carefully tracked traits by crossbreeding plants with differing characteristics and allowing them to self-breed for two years. This process enabled him to observe how traits were passed down through generations.
In his analysis, Mendel identified that traits were inherited in discrete units, or “particles.” For instance, when crossing a green pea plant with a yellow one, the offspring produced either green or yellow peas, never a mix. He also discovered dominant and recessive patterns in inheritance. When smooth-seeded plants were bred with those bearing wrinkled seeds, all offspring displayed smooth seeds, indicating that the smooth trait was dominant. Yet, about one-quarter of the plants reverted to the wrinkled appearance, revealing that the wrinkled trait was recessive and traced back to earlier generations.
Mendel’s work revealed another crucial principle: the segregation of traits. By crossbreeding plants with two different traits, he demonstrated that each trait was transmitted independently. Despite the importance of his findings, Mendel’s research went largely unrecognized during his lifetime. The term “genetics” itself was not coined until the early 1900s, when English biologist William Bateson rediscovered Mendel’s work and acknowledged its significance.
Initially, some critics dismissed Mendel’s data as “too good to be true,” suggesting he may have fabricated his results. However, a 2020 study validated his findings, showing that given the seeds and classifications available at the time, Mendel’s outcomes were consistent with what one would expect.
As research in genetics advanced, scientists uncovered complexities beyond Mendel’s initial discoveries. While his principles laid the groundwork for understanding inheritance, later studies revealed that some genes are inherited in sex-linked patterns, and traits may exhibit incomplete penetrance. In early 2026, new research suggested that certain disease-causing genes believed to be dominant do not operate as previously thought, challenging some fundamental tenets of Mendelian inheritance.
Mendel’s legacy continues to resonate in the field of genetics, influencing countless studies and fostering a deeper understanding of heredity. His journey from an underestimated friar to the “father of genetics” underscores the importance of perseverance in scientific inquiry, inspiring future generations of researchers to explore the intricacies of life.
