Gregor Mendel

Known as Father of genetics. Gregor Mendel (1822-1884) was an Austrian monk. He made first systematic approach for the investigation of the mechanism of inheritance. He did a number of experiments on inheritance in pea plants.

Mendel described the basic patterns of inheritance before genes was discovered. He called “factors” to what we now call genes. Presented the results of his experiments under name “Experiments on Plant Hybridization” before the Natural History Society of Brunn 1865 and published paper in 1866. No one realized the importance of his work until 1900.

Mendel’s brilliant and systematic work laid the foundation of a new branch of biology known as “genetics“.

Rediscovery of Mendel’s work

Mendel’s work was rediscovered by Hugo de Vries in Hollond and Carl Correns in Germany. They independently obtained the same results as those obtained by Mendel. Though Erich von Tschermak was originally also credited with rediscovery, but today he is not considered as rescoverer of Mendel’s laws as he did not understand those laws.

Why Mendel selected pea as experimental material?

  • Mendel observed that pea plant has various contrasting characters among its different varieties. He selected seven traits that are easily recognized and apparently only occur in one of two forms.
    • seed form is round or wrinkled
    • cotyledon color is yellow or green
    • seed coat color is grey or white
    • pod from is inflated or constricted
    • pod color is green or yellow
    • flower position is axial or terminal
    • stem length is tall or dwarf
  • Pea plant has perfect flowers.
  • Ordinarily self fertilized, but when cross pollination required can be easily crossed.
  • Pea plant is annual i.e. has short life cycle.
  • Can be grown and maintained in small space, with little expenditure.

Reasons for Mendel’s success

  • Proper maintenance of records i.e. observations of various characters in different generations.
  • Study of individual character so that systematic analysis is possible, no confusion.
  • Choice of material was right, reasons for this are as we have seen above.
  • Maintenance of purity, he used pure breeding parents.
  • Knowledge of shortfalls of earlier workers.
  • His mathematical background helped him a lot to understand and explain segregation of characters in F2 and F3 generations.

Mendel’s Laws

While working on pea plant Mendel proposed two laws.

Extensions (Deviations) of Mendelian concepts