Gene
Gregor Johann Mendel, an Austrian Augustinian monk in the 19th century, is known as the “father of genetics” because his experiments with pea plants in the 1850s and 1860s established the fundamental laws of inheritance:
1856–1863
Mendel spent eight years growing over 10,000 pea plants and recording their traits and offspring.
1865
Mendel presented his findings in two lectures to the Natural Science Society and published them in their journal in 1866. His work proposed that traits are inherited through generations, and that each parent can only pass on one of their hereditary characters to their offspring. Mendel's work also demonstrated how invisible "factors", now known as genes, determine an organism's traits.
1900
Mendel's work was rediscovered and verified by Hugo de Vries, Carl Correns, and Erich von Tschermak, ushering in the modern age of genetics. and this is the borning year of genetics.
Mendel’s work wasn’t appreciated during his lifetime, and after his death in 1884, the monks burned his personal papers. However, some of his letters and documents were kept in the monastery archives, and today his work is considered a foundation of modern genetics.
Why Mendel choose pea plant for his experiments
- Pea plants are annual with a short lifecycle of 2-3 months.
- Pea has many contrasting characters (Yellow, Green, Tall, Short, Round and wrinkle)
- Self-pollination is present in the plant.
- Cross pollination is performed artificially in the plant.
- Easy to breed.
- Easy to observe.
- Easy to cultivate.
- It has self pollination and cleistogamy character present.
Mendel’s 7 pair characteristic are
| No. | Characters | Dominant character | Recessive Character | Chromosome Numbers |
|---|---|---|---|---|
| 1. | Seed shape | Round | Wrinkled | 7 |
| 2. | Seed Colour | Yellow | Green | 1 |
| 3. | Flower Colour | Purple | White | 1 |
| 4. | Pod Shape | Inflated | Constricted | 4 |
| 5. | Pod Colour | Green | Yellow | 5 |
| 6. | Flower Position | Axial | Terminal | 4 |
| 7. | Stem Height | Tall | Dwarf | 4 |
Law of dominance
When two homozygous individuals with one or more contrasting characters are crossed, the characters that appear in F1 hybrid are dominant and those that do not appear in F1 are recessive characters.
- Law of dominance is not a law, it's a mendelian concept.
Law of segregation
It states that two alleles coding for the same traits remain together without being contaminated and get separate out during gamete formation.
Law of independent assortment
It states that alleles/genes for one trait will not inherit together with genes for another trait.
