`star` Genetics
`star` Early Exploration of Genetics
`star` Mendel’s experiments
`star` Plant Varieties used


● The subject of `color{violet}"Genetics"` deals with the `color{violet}"inheritance"`, as well as the `color{violet}"variation"` of characters from parents to offspring.

● `color{violet}"Inheritance"` is the process by which characters are`color{violet}" passed on"` from parent to progeny; it is the `color{violet}"basis of heredity"`.

● `color{violet}"Variation"` is the degree by which `color{violet}"progeny differ"` from their parents.


● Humans knew from as early as `color{violet}"8000-1000 B.C"`. that one of the causes of variation was hidden in `color{violet}"sexual reproduction"`.

● They exploited the variations that were naturally present in the `color{violet}"wild populations"` of plants and animals to selectively breed and select for organisms that possessed desirable characters.

● For example, through `color{violet}"artificial selection"` and `color{violet}"domestication"` from ancestral wild cows, we have well-known Indian breeds, e.g., `color{violet}"Sahiwal cows in Punjab"`.

● It must be recognized that even though our ancestors knew about the inheritance of characters and variation, they had very little idea about the `color{violet}"scientific basis of these phenomena"`.


True Breeding Line: A true breeding line is one that, having undergone continuous self-pollination, shows the stable trait inheritance and expression for several generations.

● `color{Brown}"Gregor Mendel"`, conducted hybridisation experiments on`color{violet}" garden peas"` for seven years (`color{violet}"1856-1863"`) and proposed the `color{violet}"laws of inheritance"` in living organisms.

● During Mendel’s investigations into inheritance patterns it was for the first time that `color{violet}"statistical analysis"` and `color{violet}"mathematical logic"` were applied to problems in biology.

● His experiments had a `color{violet}"large sampling size"`, which gave greater credibility to the data that he collected.

● Also, the `color{violet}"confirmation of his inferences"` from experiments on successive generations of his test plants, proved that his results pointed to `color{violet}"general rules of inheritance"` rather than being unsubstantiated ideas.

● Mendel investigated characters in the garden pea plant that were manifested as `color{violet}"two opposing traits"`, e.g., tall or dwarf plants, yellow or green seeds.

● This allowed him to set up a `color{violet}"basic framework of rules"` governing inheritance

● This was expanded on by `color{violet}"later scientists"` to account for all the diverse natural observations and the complexity inherent in them.


● Mendel conducted such artificial pollination/cross pollination experiments using several `color{violet}"true-breeding pea lines"`.

● A true breeding line is one that, having undergone `color{violet}"continuous self-pollination"`, shows the `color{violet}"stable trait inheritance"` and expression for several generations.

● Mendel selected `color{violet}"14 true-breeding"` pea plant varieties, as pairs which were similar except for `color{violet}"one character"` with `color{violet}"contrasting traits"`.

● Some of the contrasting traits selected were
`star` Smooth or wrinkled seeds

`star` `color{violet}"Yellow or green seeds"`

`star` `color{violet}"Smooth or inflated pods"`

`star` `color{violet}"Green or yellow pods"`

`star` `color{violet}"Tall or dwarf plants"`