How can we analize mendels inheritance characters of a family?
Answers
Members of a family may share similar facial features, an uncommon hair color or health problems such as diabetes.
Characteristics that run in families often have a genetic basis, meaning that they depend on genetic information a person inherits from his or her parents.
Mendel studied the inheritance of seven different features in peas, including height, flower color, seed color, and seed shape. To do so, he first established pea lines with two different forms of a feature, such as tall vs. short height. He grew these lines for generations until they were pure-breeding (always produced offspring identical to the parent), then bred them to each other and observed how the traits were inherited.
In addition to recording how the plants in each generation looked, Mendel counted the exact number of plants that showed each trait. Strikingly, he found very similar patterns of inheritance for all seven features he studied:
One form of a feature, such as tall, always concealed the other form, such as short, in the first generation after the cross. Mendel called the visible form the dominant trait and the hidden form the recessive trait.
In the second generation, after plants were allowed to self-fertilize (pollinate themselves), the hidden form of the trait reappeared in a minority of the plants. Specifically, there were always about 333 plants that showed the dominant trait (e.g., tall) for every 111 plant that showed the recessive trait (e.g., short), making a 3:1.
Mendel also found that the features were inherited independently: one feature, such as plant height, did not influence inheritance of other features, such as flower color or seed shape.