Question
Mendel's model consists of four concepts (page 209)
Describe each concept and indicate which of the concepts can be observed during meiosis by
placing an asterisk by the concept.
1.
2.
Answer
The four concepts of Mendel's model are:
1. Unit factors: These are the factors that control the inheritance of traits and are passed down from parents to offspring. They exist in pairs, with one unit factor inherited from each parent.
2. Dominance/recessiveness: When two different unit factors are inherited, one may be dominant over the other and determine the appearance of the trait, while the other is recessive and has no visible effect.
3. Segregation: During gamete formation, the two unit factors for each trait separate from each other so that each gamete receives only one of the two factors.
4. Independent assortment: The inheritance of one trait is not dependent on the inheritance of another trait, meaning that the unit factors for different traits are inherited independently of each other.
During meiosis, the concept of segregation can be observed as the homologous chromosomes separate and each gamete receives only one of the two copies of each chromosome. The concept of independent assortment can also be observed as the random alignment of homologous chromosomes during metaphase I leads to the independent inheritance of different traits.