3.1 Gregor Mendel Discored the Basic Principles of Heredity
- He used the pea plant as an experimental subject.
- Was easy to cultivate
- Peas grow rapidly. Compelting an entire geeration in a single growing season.
- Pea plants produce many offspring (seeds) which allowed Mendel to detect ratios in the traits
he observed in the progeny.
- Large numbers of variety of peas.\
- He focused on traits that exist in two easily differentiated forms.
- He was successful because he adopted an experimental approach and interpreted his results
- Gene is an inherited factor that determines a characteristic
- Genes come in different versions called alleles.
- Alleles for a particular gene are found at the locus for that gene.
- For some characters, differences between phenotypes are determined largely by differences in
genotype: in other words, the genetic limits for that phenotype are narrow.
- For other characters, environmental differences are more important; in this case, the limits
imposed by the genotype are broad.
- Only the genotype is inherite
3.2 Monohybrid Crosses Reveal the Principle of Segregation and the concept of Dominance
- Monohybrid cross: those between parents that differed in a single characteristic.
- 1 generation of a cross is the P generation.
- Offspring from parents in the P generation are the F1 generation.
- He found that the traits of the parent plants don’t blend.
- Traits are passed to f2 progeny in a 3:1 ratio.
What monohybrid crosses reveal
- He concluded that each plant must possess two genetic factors encoding a character.
- Two aleles in each plant separate when gametes are form