Experiments on Plant Hybridization (Versuche über Pflanzen-Hybriden) (1866)
Paper read to the Natural Science Society of Brünn in 1865 and published in its proceedings in 1866
Science · Biology
Gregor Mendel
1822–1884 · Austrian (Moravian-Silesian)
Genetics; heredity
Gregor Mendel was an Augustinian friar, later abbot, at St Thomas's Abbey in Brno (Brünn) who discovered the basic laws of inheritance through years of breeding experiments on pea plants. His paper of 1866 showed that traits are passed on by discrete, paired factors (now called genes) in predictable ratios. Ignored in his lifetime, his work was rediscovered in 1900 and made him the founder of genetics.
How to spot them
- ▸Monk (friar) breeding pea plants in a monastery garden in Brno
- ▸Dominant and recessive traits; the 3:1 ratio
- ▸Laws of segregation and independent assortment
- ▸Rediscovered in 1900 by Hugo de Vries, Carl Correns and Erich von Tschermak
Key discoveries & works
Pea plant breeding experiments (c. 1856–1863)
Cross-bred tens of thousands of garden pea plants, tracking seven traits such as seed shape and flower colour
Law of segregation (1866)
Each individual carries two factors for a trait, which separate so each gamete receives only one
Law of independent assortment (1866)
Factors for different traits are inherited independently of one another
Discovery of the 3:1 ratio of dominant to recessive traits (1866)
In the second hybrid generation, dominant and recessive forms appear in roughly three-to-one proportions
Key ideas
- Heredity works by discrete particles (factors, later genes), not by blending
- Dominance: one form of a trait can mask another, which reappears in later generations
- Applied statistics and large sample sizes to biology
Quick-fire facts
- •Born Johann Mendel in Heinzendorf, Austrian Silesia (now Hynčice, Czech Republic); took the name Gregor on entering the abbey in 1843
- •Studied at the University of Vienna, where Christian Doppler was among his teachers
- •Twice failed the examination to become a certified teacher
- •Became abbot of St Thomas's Abbey in 1868, after which administrative duties largely ended his research
- •Later experiments on hawkweed (Hieracium), encouraged by the botanist Carl Nägeli, failed to confirm his pea results
- •William Bateson championed his work in England and coined the word 'genetics'
- •The statistician Ronald Fisher later argued that Mendel's data fitted his expectations suspiciously well
Drill it — 7 cards
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Sources
- Robin Marantz Henig — The Monk in the Garden
- William Bateson — Mendel's Principles of Heredity: A Defence